Table 9.6.3.3

Orpen, A. G.; Brammer, L.; Allen, F. H.; Watson, D. G.; Taylor, R.

doi:10.1107/97809553602060000622

International
Tables for
Crystallography
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

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International Tables for Crystallography (2006). Vol. C. ch. 9.6, pp. 818-883

Table 9.6.3.3

A. G. Orpen,^a L. Brammer,^b F. H. Allen,^c D. G. Watson^c and R. Taylor^c

^a School of Chemistry, University of Bristol, Bristol BS8 1TS, England,^bDepartment of Chemistry, University of Missouri–St Louis, 8001 Natural Bridge Road, St Louis, MO 63121-4499, USA, and ^cCambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, England

Table 9.6.3.3 | top | pdf |
Interatomic distances (Å)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
1.1.1.1 Hydrides (terminal)								27
Fe—H	all BASLIQ10	1.609	1.610	0.004	1.605	1.612	6
Zn—H	see MAEMAZ11 (1.617)
Mo—H	see HCYPMO02 (1.684)
Rh—H	see CONFEQ01 (1.578, 1.583)
Ta—H	see TACPTH (1.769, 1.774, 1.776)
W—H	all IPPHWH01	1.732	1.734	0.010	1.725	1.740	6
Re—H	(8), (-)	1.684	1.681	0.015	1.676	1.697	12
Os—H	all THMPOS01	1.659	1.656	0.017	1.646	1.677	4
Ir—H	all DETSOK	1.603	1.607	0.021	1.582	1.623	5
Pt—H	see CAKNEH01 (1.610)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
1.1.1.2 Hydrides (μ₂-H)								27
Cr—H	see KCPTCR01 (1.725, 1.723)
Fe—H	all HMYCFE01	1.670	1.670	0.001	1.669	1.672	4
Mo—H	(6, 7), (II, III)	1.842	1.843	0.023	1.819	1.864	4
Ru—H	(^‡), (-)	1.782	1.776	0.019	1.773	1.791	22
Rh—H	(4, ^‡), (I)	1.775	1.768	0.040	1.738	1.811	8
W—H	(6), (0)	1.900	1.897	0.028	1.876	1.926	5
Re—H	(8, ^‡), (I, IV)	1.832	1.832	0.039	1.793	1.870	16
Os—H	(^‡), (-)	1.817	1.824	0.029	1.798	1.837	34
Ir—H	see CUSGAY (1.821, 1.847)
Pt—H	see CAKNEH01 (range 1.656–2.049)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
1.1.1.3 Hydrides (μ₃-H)								27
Co—H	see HMPCIC01 (1.728, 1.731, 1.742)
Ni—H	all TCPNIH11	1.691	1.684	0.022	1.673	1.715	9
Rh—H	see HMPCRH11 (1.847, 1.855, 1.873)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
1.2.1.1 BH₄ [M—(μ₂-H)—B]								28
Cu—H	see TMPCUB01 (1.698)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
1.2.1.2 BH₄ [M—(μ₂-H)₂—BH₂]
Co—H	see BEGBIY01 (1.707, 1.740)
Th—H	see MCHFHB10 (2.069, 2.120)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
2.1.1 Borohydrides [M(—H—)BH₂R]								28
Sc—B	see BOVCAQ (2.528)
Ti—B	see CPCLBT (2.178)
Cr—B	see BOSKUP (2.294)
Co—B	(-), (I): (η²-BH₄, μ₂-η¹, η^1′-BH₄)	2.218	2.224	0.030	2.199	2.241	6
Ni—B	see YBAENI (3.088)
Cu—B	see BOLJAN (2.441), CICFID (2.204, 2.232), PHRLCU (2.079), TMPCUB01 (2.517)
Zn—B	see CAPFOO (2.219), NBCZNB10 (2.252, 2.253)
Y—B	see BUWBAW (2.478, 2.836), HBTHFY (2.574, 2.680)
Zr—B	see CANFAY (2.335)
Mo—B	see HBMPMO (2.468)
Ru—B	see CIZBOC (2.237)
Os—B	see COCKOU (2.300)
U—B	(-), (III, IV): all	2.569	2.510	0.136	2.494	2.644	16
	(-), (IV): [(μ-H)₃BR]	2.493	2.498	0.040	2.459	2.515	11

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
2.2.1 Boranes/carbaboranes (not H-bridged) (see also 3.21.1)								29
Ti—B	see CEXTII (2.355, 2.375, 2.383)
V—B	see BUPLAZ10 (2.246, 2.322, 2.333)
Cr—B		2.228	2.252	0.054	2.178	2.266	9
Mn—B		2.255	2.231	0.058	2.213	2.306	9
Fe—B		2.140	2.135	0.066	2.103	2.179	111
Co—B		2.086	2.082	0.073	2.036	2.124	270
Ni—B		2.106	2.108	0.049	2.071	2.142	41
Cu—B	see BOTPCU (2.209, 2.237), TPCUBF (2.273)
Ru—B	:all	2.263	2.234	0.167	2.041	2.377	16	30
	:short < 2.10	2.035	2.033	0.012	2.026	2.046	5
	:long > 2.25	2.367	2.355	0.067	2.318	2.399	11
Rh—B		2.224	2.219	0.061	2.188	2.252	55
Pd—B		2.237	2.244	0.041	2.197	2.260	10
Ag—B	see TPACUB (2.352, 2.420, 2.522)
W—B		2.403	2.393	0.036	2.381	2.416	7
Re—B		2.292	2.287	0.056	2.239	2.349	6
Os—B	see BUVROZ (2.147, 2.184, 2.283)
Ir—B		2.236	2.205	0.083	2.183	2.287	29
Pt—B		2.243	2.244	0.062	2.213	2.283	94
Au—B		2.238	2.228	0.034	2.206	2.256	11
Hg—B	see COBHGA (2.201, 2.286), TPMCDB10 (2.204, 2.498, 2.521)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
2.2.2 Boranes/carbaboranes [M(—H—)B] (hydrogen located)								29
Mn—B		2.228	2.222	0.025	2.208	2.254	4
Fe—B	see TPCUBF (2.115)
Co—B		2.100	2.086	0.032	2.079	2.125	15
Cu—B	see TPCUBF (2.164)
Zn—B	see CEXSAZ (2.264, 2.274)
Ru—B	see COKTIF (2.327, 2.462)
Rh—B		2.342	2.330	0.040	2.311	2.384	4
W—B	see COVROU (2.413)
Ir—B	see BELJEH (2.290, 2.281), CTPIRB (2.250), TPICBO (2.452, 2.480)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
2.3.1 Boracycles (see also 3.21.2 and 4.23.1)								31–33
V—B	see BOKXEE (2.369)
Cr—B	excluding BRNOCR (2.566)	2.340	2.349	0.026	2.312	2.360	7
Mn—B		2.291	2.282	0.047	2.252	2.299	7
Fe—B		2.227	2.185	0.097	2.163	2.279	13
Co—B		2.123	2.097	0.076	2.073	2.189	12
Ni—B	see CIDBOG (2.411), CPBORN (2.175), FMBCNI (2.260), SIBONI (2.226), VIBONI (2.500, 2.550)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.1.1.1 Carbide (μ₄-C)								34, 35
Hg—C	see FAHGME (2.042)

Bond	d	m	σ	q_l	q_u	n	Note^†
3.1.1.2 Carbide (μ₅-C)							34, 35
Ru—C	2.049	2.043	0.057	2.004	2.084	40
Os—C	2.060	2.056	0.059	2.004	2.108	35

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.1.1.3 Carbide (μ₆-C)								34, 35
Ru—C		2.060	2.063	0.023	2.040	2.076	60
Rh—C	see CBACRC (2.122, 2.132, 2.125)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.2.1.1 Carbyne/alkylidyne (terminal CR, R = any C)								36, 37
C—C		1.468	1.475	0.031	1.436	1.495	18
Cr—C	(6), (-)	1.702	1.710	0.029	1.679	1.720	5	38
Mo—C	see BENFEF (1.799)
Ta—C	see BESPIY (1.850), TABYCP10 (1.849)
W—C	(5, 6), (IV, VI)	1.815	1.821	0.041	1.777	1.840	9
Re—C	see CECROR (1.742)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.2.1.2 Carbynes/alkylidynes (μ₂-CR, R = any C, H)								39
C—C		1.480	1.478	0.030	1.452	1.510	4
Ru—C	see VCPRUB10 (1.933, 1.941), CIFXOE (1.936)
W—C		1.955	1.947	0.021	1.940	1.973	6

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.2.1.3 Carbynes/alkylidynes (μ₃-CR, R = any C, H)
C—C		1.510	1.505	0.025	1.494	1.526	21
Fe—C		1.928	1.933	0.024	1.910	1.939	15
Co—C		1.896	1.895	0.035	1.874	1.920	27
Mo—C		2.059	2.056	0.019	2.042	2.075	11
Ru—C		2.084	2.089	0.027	2.067	2.102	6
Rh—C	all R = H	1.964	1.970	0.020	1.945	1.980	7
Os—C	all COTPOQ01	2.101	2.102	0.004	2.097	2.105	6

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.2.2.1 Amino carbynes (terminal CNR₂)
(M)C—N		1.322	1.334	0.053	1.271	1.368	5
N—C		1.469	1.470	0.027	1.441	1.485	8
Cr—C	see BAMCOH (1.750), SNCOCR (1.743)
Mo—C	see BITKIY (1.797)
W—C	see CAVREW (1.776, 1.747)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.2.3.1 Thiocarbynes (terminal CSR)
C—S	(1.712, 1.713)
Mo—C	see CAWSAU (1.801)
W—C	see TPCPTW (1.810)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.3.1.1 Vinylidenes/alkenylidenes (terminal CCR₂)								40
C=C		1.318	1.312	0.032	1.295	1.329	7
Fe—C	see COPMID (1.780, 1.799)
Mo—C	see BUJFIV (1.918), CVMOMP10 (1.833)
Ru—C	see BOJJUF (1.845)
Rh—C	see CAYMAQ (1.820)
W—C	see CEFVUE (1.983)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.3.1.2 Vinylidenes/alkenylidenes (μ₂-CCR₂)
C=C		1.317	1.315	0.023	1.305	1.326	7
Mn—C	see EYCCMN (1.971, 1.978)
Fe—C	see CHPECI (1.969, 1.955)
Co—C		1.885	1.885	0.021	1.864	1.904	4
Ru—C	see VCPRUA10 (2.025, 2.034)
Rh—C	see BECVOU (1.987, 1.989)
Os—C	see BEXJUJ (2.096, 2.102)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.4.1.1 Acetylides/alkynyls (terminal CCR)
C≡C		1.188	1.188	0.017	1.178	1.202	16
C—C		1.456	1.451	0.030	1.436	1.465	16
V—C	see CIJLUC (2.074)
Fe—C	see CPFPEY (1.920)
Rh—C	see BIMTEW (1.939)
Pd—C	see EYPIPD (1.953)
W—C	see BONSUS (2.134)
Ir—C	see CEFPEI (2.041)
Pt—C	(4, 6), (II, IV)	1.992	2.000	0.032	1.985	2.009	8	41
Hg—C	see PEYHGP (2.047, 2.031)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.4.1.2 Acetylides/alkynyls (μ₂-CCR)^§								42
C—C		1.231	1.232	0.026	1.206	1.256	4
Fe—Cσ	see ACYPCI (1.890)
—Cπ	(2.117, 2.283)
Ru—Cσ	see BAYCOS (2.047), BOBTOB (2.044)
—Cπ	see BAYCOS (2.323, 2.423); BOBTOB (2.285, 2.508)
Pt—Cσ	see MSIPEP (1.964)
—Cπ	see MSIPEP (2.141, 2.468)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.5.1.1 Cyano (terminal CN)								43
C—N		1.146	1.146	0.014	1.138	1.154	168
V—C	see CIRSAX (2.067), CIRSEB (2.088)
Cr—C	(6), (-): all	2.058	2.063	0.024	2.031	2.080	8	7
Mn—C	see CAZJAO10 (1.996, 1.989)
Fe—C	(5, 6), (0, II, III): all	1.937	1.935	0.023	1.923	1.950	33
Co—C	(5, 6), (-): all	1.896	1.900	0.019	1.883	1.907	50	8
Ni—C	(4, 5), (-): all	1.883	1.868	0.076	1.852	1.873	30
	excluding 2 > 2.1	1.864	1.868	0.021	1.851	1.872	28
Cu—C	(3, 5), (-): all	2.003	1.975	0.101	1.924	2.098	5	12
Zn—C	(4), (-): all	2.000	1.997	0.012	1.991	2.013	4
Mo—C	(6, 7, 8), (-): all	2.167	2.166	0.021	2.155	2.184	21	15, 44
Ru—C	see BEPJIP (2.025)
Pd—C	see BEJHUT (1.997)
Ag—C	see COLSEB (2.093)
Pt—C	(4, 5), (II): all	1.943	1.931	0.031	1.916	1.977	5
Au—C	see CIGCOK (2.003)
Hg—C	see BINRAR (2.187, 2.174), CAHRUY (2.100)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.5.1.2 Cyano (μ₂-CN)^§ (see also 4.4.2)
C—N		1.143	1.147	0.016	1.132	1.153	21
Cr—C	see CYCRTF (1.999, 1.972, 1.965)
Mn—C	see CAZJAO10 (1.995)
Fe—C	(6), (III)	1.948	1.942	0.025	1.928	1.972	6
Ni—C	(4), (II)	1.859	1.853	0.017	1.847	1.877	4
Cu—C	(4), (I)	1.951	1.965	0.030	1.914	1.974	6	12
Pd—C	see BUSRIQ (2.011)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.6.1.1 Isocyanides (terminal CNR, R = any C)								45, 46
C—N		1.149	1.147	0.016	1.139	1.157	220
V—C	see CIRSAX (2.003), CLBCNV (2.189)
Cr—C	(6, 7), (0–III): R = Ph, ^tBu, Bz	1.996	2.003	0.038	1.969	2.014	21	7
Mn—C	(6), (-): R = Ph, ^tBu, Me	1.927	1.924	0.028	1.900	1.947	15
Fe—C	(5, 6, ^‡), (0–II): all	1.862	1.867	0.048	1.819	1.901	12
	(6), (II): all	1.874	1.874	0.043	1.832	1.901	7
Co—C	see BISJOC (1.851, 1.846, 1.866)
Ni—C	(3, 4), (0): R = ^tBu	1.853	1.854	0.021	1.838	1.870	6
Cu—C	(3, 4), (I): R = ^tBu, p-Tol, cyh	1.896	1.895	0.009	1.890	1.905	7
Nb—C	(7, 8), (-): R = ^tBu	2.241	2.237	0.036	2.208	2.270	6
Mo—C	(5–8), (0–IV)	2.107	2.115	0.040	2.089	2.135	61	15
	(5–8), (II)	2.111	2.115	0.032	2.094	2.131	56
	(5–7), (II): R = ^tBu	2.108	2.115	0.030	2.089	2.125	36
Ru—C	(6, ^‡), (-)	1.986	1.997	0.040	1.941	2.014	7
Rh—C	(4–6), (-)	1.968	1.969	0.036	1.955	1.983	21
	(4), (-)	1.956	1.962	0.031	1.947	1.975	13
Pd—C	(3–5), (-)	1.985	1.974	0.036	1.958	2.020	18	47
	(4), (-)	1.978	1.972	0.035	1.955	1.994	15
Ag—C	see BUXGAC (2.162, 2.136)
Pr—C	see CXINPR10 (2.654)
W—C	(7), (II): R = ^tBu	2.102	2.105	0.035	2.070	2.125	11
Re—C	(6, 7), (I–II)	2.002	2.008	0.022	1.980	2.018	12
Os—C	see CIRJAO (1.983, 2.004), HOSTBC10 (2.032)
Ir—C	see MCPEIR (1.945), MICPIR10 (1.986)
Pt—C	(4, 5, ^‡), (-)	1.936	1.924	0.059	1.896	1.968	13
	(4, 5), (-)	1.944	1.966	0.036	1.912	1.968	7

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.6.1.2 Isocyanides (μ₂-CNR)
C—N		1.221	1.227	0.038	1.196	1.241	15
Fe—C		1.941	1.941	0.025	1.920	1.948	12
Ni—C	all MINCNI	1.881	1.880	0.022	1.861	1.903	4
Os—C	see HYBIOS (2.072, 2.039)
Pt—C	all BIDCAS	2.100	2.086	0.070	2.038	2.170	12

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.7.1.1 Carbon monoxide (terminal CO)								48
C—O		1.145	1.143	0.020	1.132	1.156	10022
Ti—C		2.003	1.997	0.030	1.980	2.030	5	49
V—C		1.946	1.946	0.037	1.924	1.974	60
Cr—C		1.866	1.867	0.037	1.835	1.895	925	38
Mn—C		1.808	1.805	0.034	1.784	1.833	789
Fe—C		1.782	1.784	0.030	1.765	1.801	2572	50
Co—C		1.780	1.781	0.034	1.758	1.801	662
Ni—C		1.771	1.776	0.029	1.750	1.794	34	51
Cu—C		1.787	1.782	0.019	1.776	1.807	18	12
Zr—C	see CCPZRA (2.187)							49
Nb—C		2.073	2.073	0.028	2.056	2.092	26
Mo—C		1.978	1.973	0.041	1.947	2.007	748	15
Tc—C		1.884	1.883	0.021	1.866	1.904	4	17
Ru—C		1.896	1.896	0.036	1.873	1.919	1453
Rh—C		1.847	1.846	0.040	1.821	1.869	238
Ta—C	see BISZIM (2.036), BUVGII (2.083), CPMPTA (2.008)
W—C		2.002	2.007	0.043	1.971	2.034	508	24
Re—C		1.936	1.933	0.050	1.898	1.978	370
Os—C		1.902	1.903	0.036	1.880	1.927	1443
Ir—C		1.870	1.876	0.042	1.839	1.898	148
Pt—C		1.853	1.854	0.056	1.821	1.878	29

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.7.1.2 Carbon monoxide (μ₂-CO)								52
C—O		1.171	1.171	0.022	1.159	1.183	279
Mn—C	(all)	1.940	1.930	0.021	1.926	1.955	8
	(M—C—M < 70°)	1.929	1.928	0.005	1.924	1.933	6
Fe—C	(all)	1.941	1.925	0.041	1.914	1.971	104
	(M—C—M < 80°)	1.985	1.995	0.037	1.953	2.018	20
	(80° < M—C—M < 86°)	1.930	1.921	0.034	1.908	1.946	80
Co—C		1.914	1.919	0.046	1.883	1.947	114
Ni—C		1.882	1.880	0.021	1.870	1.892	14
Cu—C		1.861	1.862	0.015	1.854	1.872	6
Mo—C	(all)	2.127	2.091	0.095	2.045	2.237	6
	(Mo=Mo only)	2.068	2.064	0.027	2.045	2.095	4
Ru—C	(all)	2.072	2.055	0.047	2.038	2.099	66
	(non-clusters)	2.040	2.039	0.021	2.026	2.055	20
	(clusters)	2.086	2.087	0.048	2.043	2.114	46
Rh—C	(all)	2.040	2.037	0.055	1.994	2.076	180
	(M—C—M < 85°)	2.057	2.058	0.059	2.000	2.111	106
	(85° < M—C—M < 95°)	2.018	2.029	0.037	1.984	2.046	68
	(M—C—M > 115°)	1.983	1.982	0.007	1.977	1.990	4
Pd—C	(all)	2.004	1.997	0.039	1.979	2.015	14
Re—C	(all BAWTOI)	2.073	2.072	0.009	2.063	2.080	6
Os—C		2.081	2.063	0.057	2.042	2.122	6
Ir—C		2.065	2.072	0.039	2.026	2.093	30
Pt—C		2.044	2.039	0.032	2.018	2.063	6

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.7.1.3 Carbon monoxide (μ₃-CO)								42
C—O		1.190	1.191	0.038	1.173	1.202	33
Fe—C		2.002	1.990	0.037	1.980	1.997	15
Co—C		1.950	1.949	0.032	1.937	1.962	15
Ni—C	see TCPDNI01 (1.931, 1.932)
Ru—C		2.171	2.169	0.020	2.153	2.193	8
Rh—C	see POSHRH10 (2.205, 2.155, 2.238)
Pd—C	see BUJYIO (2.190, 2.078, 2.157)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.8.1.1 CS (terminal)
C—S		1.563	1.570	0.030	1.536	1.587	5
Cr—C	see BUGRIE (1.778), MBZCRC (1.797), TLCSCR (1.751)
Mn—C	see ICPNMN (1.803)
Fe—C	see BEPDEF (1.662)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.8.1.2 CS (μ₂-CS)
C—S	(1.597, 1.606, 1.618)
Fe—C	all CPTCFF	1.886	1.889	0.007	1.878	1.891	4

Bond	Substructure (coordination number, oxidation state, comment)	Note^†
3.9.1.1 Carbene/alkylidene (terminal CH₂)		36
Re—C	see CAHZUG (1.898)
Os—C	see CAMTEP (1.924)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.9.1.2 Carbenes/alkylidenes (μ₂-CR₂, R = any C, H)								39, 53
Mn—C	see BANGIG10 (2.026), MYCCMN10 (2.018, 2.019)
Fe—C		2.006	1.990	0.045	1.974	2.052	6
Co—C		1.934	1.925	0.025	1.909	1.961	7
Ru—C		2.085	2.095	0.056	2.076	2.112	12
Rh—C		2.048	2.059	0.033	2.017	2.075	15
W—C	excluding BIJJAF (2.127, 2.436)	2.298	2.296	0.035	2.266	2.331	4
Re—C	all CEHFEA	2.141	2.132	0.030	2.119	2.171	4
Os—C	excluding CODCON (1.922, 1.909)	2.160	2.155	0.041	2.136	2.192	20
Au—C		2.112	2.102	0.026	2.095	2.139	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.9.2.1 Carbenes/alkylidenes (terminal CHR)
C—C		1.490	1.493	0.027	1.462	1.513	14
Ta—C	(5, 6, 8), (V): all	1.963	1.938	0.065	1.932	2.030	7	54, 55
W—C	(5–7), (IV, VI)	1.953	1.942	0.086	1.871	2.041	5	38, 55
Re—C	see BOBYAS (1.949), CECROR (1.873)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.9.3.1 Carbenes/alkylidenes (terminal CR₂)
C—C	[R = C (sp³)]	1.503	1.509	0.024	1.500	1.519	12
Mn—C	see CERJIS (1.853), MCBCMN (1.864, 1.871)
Fe—C	see CPCFEA10 (1.978)
W—C	see DPCBWC (2.132, 2.154)							38, 55
Ir—C	see PYBPIR (1.998)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.9.4.1	Alkoxy carbenes [terminal CR(OR), R = any C]
(M)C—O		1.318	1.314	0.023	1.300	1.338	18
(M)C—C		1.501	1.503	0.032	1.479	1.524	18
O—C		1.466	1.459	0.024	1.452	1.484	18
Cr—C	(6), (-)	2.012	2.006	0.029	1.988	2.039	5	38, 55
Mn—C	see BOCWAR (1.848), MNXCMN (1.890), NPMCMN (1.950)							55
Co—C	see PGECBC (1.912)
Mo—C	see BEBTUX (2.087)
W—C	(6), (-)	2.161	2.161	0.014	2.148	2.175	4
Re—C	see CMNCBR (2.098)
Os—C	see BODGUW10 (1.981)
Pt—C	see CIPTMN (1.889), EOBCPT10 (1.920)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.10.1.1 Vinyls (σ-CRCR₂)^§								41
C=C		1.345	1.344	0.024	1.333	1.357	98
Ti—C	(8), (IV)	2.215	2.239	0.042	2.171	2.243	7
Cr—C	all MPEYCR10	2.035	2.033	0.009	2.027	2.045	4
Mn—C	see BIZJEZ (1.985), CECCIW (2.009), MASBCM (2.027)
Fe—C	(5, 6), (II)	1.991	1.997	0.039	1.954	2.030	10
Co—C	(6), (-)	1.934	1.932	0.019	1.914	1.946	8
Ni—C	(4, 5), (-)	1.892	1.900	0.017	1.874	1.903	4
Zr—C	see CPPHZR (2.249, 2.265)
Mo—C	(7), (-)	2.204	2.223	0.049	2.151	2.247	5
Ru—C	see CNBRUB (2.073), CXFMPR (2.082), PCFMRU10 (2.034)
Rh—C		2.040	2.060	0.054	1.986	2.085	5
Pd—C	(4), (II)	2.000	2.006	0.024	1.989	2.011	16	47
Hf—C	see CPTPHF (2.190, 2.219)
W—C	see BEDGAS (2.202), COPMEZ (2.275), MCTCEW (2.194)
Os—C	see CIRNOG (2.052)
Ir—C	(5, 6), (-)	2.071	2.073	0.044	2.036	2.103	6
Pt—C	(4,5), (-)	2.024	2.022	0.037	1.991	2.058	17	41
Au—C	see BULPED (2.039, 2.045)

Bond	d	m	σ	q_l	q_u	n
3.10.1.2 Vinyls (η²-CRCR₂)^§
C_α—C_β	1.408	1.407	0.013	1.418	1.442	8
Mo—C_α	1.936	1.937	0.020	1.917	1.954	4
—C_β	2.292	2.293	0.027	2.265	2.316	4
W—C_α	1.918	1.907	0.030	1.898	1.949	4
—C_β	2.251	2.249	0.078	2.181	2.324	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.10.1.3 Vinyls (μ₂-η¹, η²-CRCR₂)^§								39
C_α—C_β		1.408	1.407	0.022	1.395	1.421	43
Mn¹—C_α	see BOWYOB (2.058, 2.053)
Mn²—C_α	see BOWYOB (2.086, 2.102)
—C_β	see BOWYOB (2.263, 2.263)
Fe^l—C_α		1.996	2.004	0.036	2.000	2.009	8
Fe²—C_α		2.102	2.095	0.039	2.079	2.111	8
Fe²—C_β		2.219	2.197	0.046	2.183	2.260	8
Co¹—C_α	see BOCCOC (1.973, 1.968), BULYOW (1.981)
Co²—C_α	see BOCCOC (2.009, 2.011), BULYOW (1.995)
—C_β	see BOCCOC (2.132, 2.115), BULYOW (2.127)
Mo¹—C_α	see BEDDAP (2.151, 2.140), CAMKIK (2.141)
Mo²—C_α	see BEDDAP (2.181, 2.181), CAMKIK (2.232)
—C_β	see BEDDAP (2.301, 2.301), CAMKIK (2.446)
Ru¹—C_α		2.079	2.075	0.043	2.060	2.089	13
Ru²—C_α		2.221	2.227	0.057	2.191	2.260	13
—C_β		2.276	2.276	0.042	2.247	2.284	13
Rh¹—C_α	see BATNIT (2.045), FMPENR (2.025, 2.028)
Rh²—C_α	see BATNIT (2.100), FMPENR (2.058, 2.102)
—C_β	see BATNIT (2.222), FMPENR (2.139, 2.205)
W¹—C_α	(6, 7), (0, II, IV): all	2.158	2.145	0.043	2.128	2.203	6
W²—C_α	(6), (IV): excluding 2.266, 2.124	2.412	2.412	0.034	2.380	2.445	4
—C_β	(6), (II, IV): excluding 1 at 2.220	2.458	2.470	0.047	2.410	2.500	5
Re¹—C_α	see COTFAS (2.170, 2.098)
Re²—C_α	see COTFAS (2.359, 2.255)
—C_β	see COTFAS (2.352, 2.307)
Os²—¹C_α	see CHVINO (2.108), HPETOS (2.154), UCHXOS (2.170)
Os²—C_α	see CHVINO (2.273), HPETOS (2.151), UCHXOS (2.188)
—C_β	see CHVINO (2.362), HPETOS (2.300), UCHXOS (2.311)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.11.1.1 σ-Aryls (η¹-Ar)^§
C^l—C²		1.396	1.396	0.021	1.381	1.409	398
C²—C³		1.393	1.392	0.022	1.379	1.406	398
C³—C⁴		1.378	1.379	0.025	1.364	1.395	399
Ti—C	see PFPBTI (2.135), PSIBTI (2.161)
V—C	(4, 6), (II, III)	2.114	2.115	0.012	2.102	2.124	4
Cr—C	(5, 6), (II, III)	2.075	2.072	0.019	2.061	2.089	10	38
Mn—C	(6), (I)	2.064	2.059	0.021	2.044	2.083	6
Fe—C	(4, 6), (I, II)	2.031	2.022	0.062	1.985	2.065	6
	(6), (I, II)	2.008	2.021	0.021	1.974	2.030	5
Co—C	see DMDECO01 (1.995), ETPSCO10 (1.997), TOPFCO10 (1.931)
Ni—C	(4, 5), (II, III)	1.917	1.929	0.038	1.893	1.942	18
Cu—C	see CODJIO (2.020)
Mo—C	(4, 5, 7), (0, II, IV): all	2.193	2.176	0.054	2.164	2.195	11	38
	(4, 5), (II, IV)	2.172	2.169	0.016	2.160	2.187	9
Ru—C	(5, 6), (II)	2.092	2.121	0.057	2.013	2.136	7
Rh—C	(5, 6), (II, III)	2.011	2.000	0.026	1.990	2.037	9
Pd—C	(4, ^‡), (II): all	1.981	1.987	0.032	1.965	2.002	28	47
Lu—C	see CILCUV (2.425, 2.427, 2.455)
Ta—C	(5), (V)	2.199	2.173	0.073	2.147	2.276	4
Re—C	see PHTPRE (2.024, 2.029)
Os—C	(6, ^‡), (-)	2.090	2.092	0.032	2.058	2.120	4
Ir—C	(4–6, ^‡), (I, III): all	2.070	2.067	0.038	2.043	2.092	17
	(6), (III)	2.053	2.049	0.024	2.037	2.071	10
Pt—C	(4–6), (I, II, IV): all	2.049	2.061	0.046	2.033	2.079	35	41
	(4), (I, II)	2.055	2.062	0.039	2.043	2.079	28
Au—C	(2–4, ^‡), (I, III): all	2.059	2.062	0.024	2.052	2.073	22
	(2, 3), (I)	2.053	2.050	0.009	2.045	2.062	5
	(4), (III)	2.062	2.068	0.031	2.055	2.081	13
Hg—C	(2–4, ^‡), (II): all	2.086	2.088	0.040	2.054	2.120	24
	(2, 3), (II)	2.053	2.057	0.027	2.040	2.075	12
	(^‡), (-): all BIPHHG	2.120	2.119	0.014	2.115	2.126	12

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.12.1.1 Acyls [η¹-C(O)R]^§
C=O		1.210	1.209	0.023	1.195	1.218	60
Mn—C	see PNMNCP (2.012), PYRMNC (2.076)
Fe—C	(6), (II)	1.997	2.004	0.033	1.967	2.028	18
Co—C	see BOBSUG (1.915), OXCOCP10 (2.055)
Ni—C	(4, 5), (II)	1.850	1.870	0.059	1.788	1.893	4
Mo—C	see BOLCIO10 (2.049), MABUMO10 (2.168)
Ru—C	see BEWMAR (2.091)
Rh—C	(5, 6), (III): all	1.995	1.996	0.031	1.969	2.006	10
Pd—C	(4), (II): all	1.982	1.992	0.029	1.951	2.002	4
Re—C	(6), (I)	2.190	2.183	0.027	2.175	2.214	7
Os—C	see BUYMAJ (2.161)
Ir—C	see NRBIRB (1.971), POIRID (2.067)
Pt—C	(4), (II)	1.991	2.000	0.025	1.969	2.008	7

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.12.1.2 Acyls [η²-C(O)R]^§ (see also 5.25.1)
C=O		1.240	1.238	0.014	1.227	1.248	10
Zr—C	see BOPSII (2.181, 2.186)
Mo—C		2.014	2.020	0.011	2.003	2.023	6
W—C	see BUSYIX (2.030), COSSOS (2.000)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.13.1.1 Methyl (terminal CH₃)
Ti—C	see BASMOX (1.969), INDMTI (2.206)
Cr—C	see CAMVER (2.168)
Mn—C	(6), (IV): all CAJHOK	2.095	2.105	0.030	2.068	2.124	4
Fe—C	see BNTLFE (2.080), CEDMON (2.065), CMZTFE (2.077)							50
Co—C	(6), (III)	2.014	2.014	0.023	1.993	2.032	16
Ni—C	see BAPKEI (2.035), PEAMNI (2.023)							56
Zr—C	IV, (4–6, 8)	2.292	2.279	0.049	2.257	2.346	8
Nb—C	see CPSNBA (2.346), CPSNBB (2.327)							54
Mo—C	(5–7), (II–IV, VI): all	2.254	2.282	0.065	2.189	2.296	15
Ru—C	(5, 6), (II)	2.179	2.156	0.045	2.143	2.226	5
Rh—C	(5, 6), (II, III)	2.092	2.101	0.027	2.064	2.113	4
Hf—C	(8), (IV)	2.275	2.267	0.049	2.233	2.325	4
Ta—C	(6, 7), (III, V)	2.217	2.215	0.035	2.181	2.247	7	54
W—C	(4–6), (II, III, VI)	2.189	2.187	0.039	2.166	2.213	13
Re—C	(5, 6), (I, III)	2.173	2.188	0.051	2.123	2.201	8
Ir—C	see BEJBEX (2.218), CODPIR10 (2.133)
Pt—C	(4–6), (II, IV): all	2.083	2.077	0.045	2.047	2.117	58	41
	(4, 5), (II)	2.107	2.115	0.044	2.069	2.136	30
	(6), (IV)	2.057	2.056	0.028	2.038	2.077	28
Au—C	(4), (III)	2.066	2.045	0.045	2.030	2.118	18	57
Hg—C	(2–4), (II)	2.072	2.071	0.026	2.056	2.092	29
Th—C	see COSZOZ (2.567)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.13.2.1 Primary alkyls [CH₂R, R = C(sp³)]
C—C		1.521	1.528	0.033	1.512	1.540	90
Ti—C	see BILWIC (2.138, 2.152), BOYZOE (2.210)
Mn—C	(4, 6), (I, II)	2.176	2.173	0.024	2.154	2.199	5
Fe—C	(6), (II)	2.091	2.082	0.030	2.071	2.102	8
Co—C	(6), (II, III)	2.039	2.037	0.032	2.018	2.061	14
Ni—C	see ACTPEN (1.970), BENIIB (1.973), DIPNIP (1.948)							56
Zn—C	see PMCZNE (1.964)
Nb—C	see CPETNB (2.316), ONBCBU (2.322)							54
Mo—C	(4–8), (II–IV, VI): all	2.250	2.252	0.061	2.208	2.272	12
	(4–8), (III, IV, VI)	2.230	2.234	0.042	2.195	2.269	10
Ru—C	(4), (III): all CIBGEZ	2.036	2.033	0.010	2.029	2.045	6
Rh—C	see CIDJEE (2.094), PBUDRI10 (2.098, 2.107)
Pd—C	see BIHLOT01 (2.051), HIMPDA (2.009, 2.023)
Ta—C	(5, 7), (V)	2.225	2.208	0.056	2.183	2.289	6	54
W—C	see COPXIO (2.141, 2.126), DMPMPW10 (2.257)
Re—C	see COMPRH (2.285), ETDYRE (2.296)
Os—C	see BOTTAF (2.220, 2.219), BUYNEO (2.203)
Pt—C	(4–6), (II, IV)	2.062	2.065	0.031	2.039	2.085	14	41
Hg—C	see CIRMAR (2.125)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.13.3.1 Primary alkyl [CH₂R, R = C(sp²)]
C—C		1.477	1.478	0.028	1.464	1.496	108
Ti—C	see CEYCOY (2.203, 2.204)
Cr—C	see BELTUH (2.101)
Mn—C	see ACPMNA (2.209), BUFLET (2.199), CABYUZ (2.127)
Fe—C	(5, 6), (0, II)	2.131	2.133	0.038	2.098	2.155	9
Co—C	(5, 6), (-)	2.061	2.085	0.061	2.001	2.109	5
Ni—C	see IPRNIP (1.977)							56
Zn—C	see CLPDZN (2.030)
Zr—C	(8), (IV)	2.320	2.306	0.034	2.298	2.355	4
Nb—C	(8), (IV, V)	2.289	2.291	0.024	2.271	2.306	14	54
Mo—C	(4–6), (II, III, VI)	2.211	2.214	0.027	2.187	2.233	9
Ru—C	see CALHIG (2.200)
Rh—C	see CIHYOH (2.103)
Pd—C	(4, 5, ^‡), (II, -)	2.050	2.044	0.042	2.019	2.071	20
Hf—C	see CEYCUE (2.274, 2.284)
Ta—C	see CBZYTA (2.304), CPBZTB (2.188, 2.233)							54
W—C	(5–8), (II, III, V): all	2.238	2.185	0.090	2.163	2.328	9
Re—C	see BUVSOA (2.203), BZHREC (2.284)
Os—C	see BUYMAJ (2.217)
Ir—C	see BIYJIC (2.127), CIYKAW (2.167), POIRID (2.133)
Pt—C	(4, 5), (II)	2.067	2.081	0.033	2.032	2.089	4	41
Hg—C	see CHGACA (2.107), DBEZHG (2.064)
Th—C	all CEKGEE	2.554	2.555	0.022	2.535	2.570	7
U—C	(6, 10), (IV)	2.509	2.521	0.039	2.468	2.539	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.13.4.1 Secondary alkyls [terminal CHR₂, R = C(sp³)]
C—C		1.532	1.534	0.033	1.510	1.554	72
Fe—C	see BULLFE (2.168), CAGKEA (2.060), MEDOFE10 (2.079)
Co—C	(6), (III)	2.086	2.090	0.028	2.058	2.111	4
Ni—C	see CONBIQ (1.929)							56
Zr—C	see CALNUY (2.381)
Ru—C	(5, 6), (II)	2.145	2.153	0.032	2.112	2.171	4
Rh—C	see HBUPRH (2.083)
Pd—C	(4, 5), (II)	2.035	2.041	0.036	2.003	2.051	9
Ir—C	(5, 6), (III)	2.107	2.107	0.035	2.074	2.141	7
Pt—C	(4, 5), (II)	2.078	2.073	0.038	2.046	2.116	4	41
Hg—C	see CHGALD (2.085)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.13.5.1 Secondary alkyls {CHR₂, R₂ ≠ [C(sp³)₂]}
C—C	R = C(sp²)	1.474	1.475	0.023	1.461	1.485	82
	R = C(sp³)	1.532	1.527	0.022	1.518	1.545	40
Ti—C	see TCYPTI10 (2.332)
Fe—C	(5, 6), (-)	2.131	2.138	0.027	2.110	2.151	16
Co—C	(6), (-)	2.075	2.086	0.029	2.052	2.093	5
Zr—C	see PDPMZR10 (2.379, 2.396)
Mo—C	see BIRLIX (2.405)
Ru—C	see BDMFRU (2.180), CTERUC (2.138)
Rh—C	see BIGHAA (2.192), CASDIJ (2.154)
Pd—C	(4, 5), (II)	2.083	2.092	0.040	2.052	2.106	11
Re—C	(6), (I)	2.311	2.335	0.065	2.243	2.356	4
Os—C	see BUYNEO (2.221), CINKAL (2.215), EYPCOS (2.185)
Ir—C	see CAYGAK (2.420)
Pt—C	(4, 5), (II)	2.113	2.120	0.036	2.082	2.141	9	41
Au—C	see BAJZAN (2.146), CEPYIF (2.175)							57
Hg—C	see BAVMUG (2.122), TPHGDI10 (2.292)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.13.6.1 Tertiary alkyls (terminal CR₃, R = any C)
C—C		1.501	1.502	0.045	1.468	1.534	84	109
Fe—C	(5, 6), (II)	2.127	2.128	0.027	2.098	2.153	6
Co—C	see COJBOS (2.154)
Zn—C	see COPLEY (2.050)
Mo—C	see CYPRMO (2.414)
Pd—C	(4), (II)	2.147	2.150	0.040	2.140	2.174	8
Pt—C	(4), (II)	2.148	2.139	0.028	2.133	2.162	9	41
Au—C	see BENNOX (2.213), BUJXAF (2.197)							57

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.13.7.1 Trifluoromethyl (terminal CF₃)
C—F		1.347	1.343	0.030	1.329	1.355	22
Pt—C	(4, 5), (II)	2.098	2.087	0.057	2.056	2.146	5

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.14.1 η²-Ethene (C₂H₄)
C=C		1.392	1.390	0.044	1.363	1.415	43
Co—C	(5), (I)	2.035	2.033	0.012	2.025	2.048	4
Ni—C	(3, 4), (0)	1.985	1.978	0.025	1.970	1.989	18
Cu—C	(3, 4), (I)	2.010	2.011	0.011	2.001	2.019	6	12
Nb—C	see CPETNB (2.278, 2.320)							54
Ru—C	(6), (II)	2.198	2.204	0.022	2.174	2.215	4
Rh—C	(4, 5), (I)	2.129	2.135	0.033	2.091	2.160	12
Ta—C	see NPNTAB (2.228, 2.285)							54
W—C	(5, 6), (-)	2.205	2.185	0.043	2.176	2.246	8
Ir—C	see CETPIR (2.124, 2.111)
Pt—C	(3, 4, ^‡), (0, II)	2.172	2.176	0.042	2.143	2.193	28	41, 58

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.14.2 η²-Alkenes (CH₂CHR, R = any C)								59
C=C		1.383	1.383	0.033	1.361	1.404	44
Fe—C	(5), (0)	2.090	2.088	0.012	2.079	2.102	4	58, 60
Co—C	(5), (I)	2.084	2.085	0.034	2.052	2.115	4
Ni—C	(4, 5), (II)	2.035	2.039	0.053	1.984	2.082	4	9, 58, 61
Cu—C	(3, ^‡), (I)	2.060	2.061	0.025	2.046	2.080	6	12
Mo—C	(6), (0, II)	2.282	2.271	0.027	2.265	2.310	4
Ru—C	(5, 6), (-)	2.198	2.190	0.034	2.171	2.232	4
Rh—C	(4, 6), (I, -)	2.172	2.164	0.058	2.118	2.216	10
	(4), (I)	2.150	2.141	0.040	2.117	2.194	8
Pd—C	(4, 5), (II)	2.189	2.179	0.040	2.151	2.233	12
Ag—C	(3–5), (I)	2.535	2.542	0.050	2.486	2.582	6
W—C	(6), (0): all	2.386	2.410	0.080	2.302	2.454	10	30
	: short < 2.35 (trans to C=C)	2.299	2.298	0.010	2.290	2.308	4
	: long > 2.40 (trans to CO)	2.443	2.434	0.036	2.412	2.484	6
Ir—C	see COPNIR (2.179, 2.162)
Pt—C	(4), (II)	2.179	2.173	0.051	2.139	2.205	22	41

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.14.3 η-Alkenes (CH₂CR₂, R = any C)
C=C		1.387	1.396	0.029	1.354	1.413	8
Fe—C	(5), (0)	2.124	2.119	0.065	2.072	2.188	6	60
Ru—C	see BOVLUT (2.168, 2.203)
Pd—C	see CARJOU (2.187, 2.107)
Ag—C	all CIXYAJ	2.421	2.419	0.081	2.345	2.499	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.14.4 η²-Alkenes (CHRCHR, R = any C)								62
C=C		1.391	1.389	0.032	1.372	1.407	280
V—C	see EFMCPV (2.213, 2.186)
Cr—C	see MOBOCO10 (2.248, 2.300)
Mn—C	see CPTOMN (2.193, 2.203)
Fe—C	(5, 6), (0, II): all	2.134	2.143	0.063	2.079	2.183	22
	: R electron withdrawing	2.067	2.072	0.022	2.041	2.087	8
	: R = alkyl	2.172	2.169	0.041	2.144	2.195	14
Co—C	all NBPCCO	2.138	2.137	0.005	2.134	2.144	4
Ni—C	(3–5), (0, II): all	2.057	2.054	0.050	2.000	2.095	17	9, 58, 61
	: R electron withdrawing	1.991	1.997	0.015	1.979	2.000	5
	:1,5-cod	2.084	2.089	0.028	2.052	2.107	12
Cu—C	(3, 4, ^‡), (I): all	2.079	2.079	0.033	2.063	2.089	20	12
Mo—C	(6), (0, II) : all	2.369	2.347	0.083	2.298	2.446	28
	: trans to CO	2.468	2.463	0.039	2.428	2.499	10
	: not trans to CO	2.314	2.310	0.034	2.284	2.346	18
Ru—C	: all	2.223	2.196	0.076	2.172	2.251	64	63
	: nbd, 1,5-cod only	2.191	2.187	0.036	2.167	2.206	49
Rh—C	(4–6, ^‡), (I–III): all	2.157	2.143	0.049	2.123	2.188	206
	: nbd, 1,5-cod only	2.156	2.143	0.047	2.122	2.189	184
Pd—C	(4), (II)	2.214	2.208	0.037	2.194	2.221	30
Ag—C	see BUZMUE (2.705, 2.611)
W—C	(6), (-)	2.430	2.430	0.033	2.400	2.457	6
Re—C	see BAXLER (2.275)
Os—C	: all R electron withdrawing	2.167	2.176	0.033	2.133	2.193	4
Ir—C	(4–6, ^‡), (I, III): all	2.170	2.160	0.061	2.124	2.200	94
	: 1,5-cod only	2.163	2.160	0.051	2.124	2.186	76
Pt—C	(4, 5, ^‡), (0, II): all	2.209	2.223	0.056	2.173	2.252	52	41, 58
	: 1,5-cod only	2.230	2.236	0.039	2.193	2.254	40

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.14.5 η²-Alkenes (CHRCR₂, R = any C)
C=C		1.411	1.403	0.025	1.392	1.427	12
Mo—C	see OCTCMO10 (2.211, 2.227)
Ru—C	see CXFMPR (2.171, 2.184)
Rh—C	(4, 5), (I)	2.130	2.121	0.023	2.111	2.155	14
Ir—C	all COTFEW	2.148	2.150	0.020	2.130	2.165	4
Pt—C	see COTFPT (2.059, 2.072)							41, 58

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.14.6 η²-Alkenes (CR₂CR₂, R = any C)
C=C		1.436	1.438	0.044	1.415	1.454	15
Fe—C	: all	2.144	2.085	0.127	2.048	2.269	8
	: excluding trans to CO	2.079	2.058	0.045	2.045	2.121	6
Co—C	see EXPHCO (2.084, 2.134)
Mo—C	see CPOMOA (2.231, 2.234)
Rh—C	(4, 5), (I)	2.175	2.173	0.025	2.153	2.199	4
Pd—C	(4), (II)	2.248	2.258	0.055	2.191	2.296	4
Ag—C	see BUGGAL (2.472, 2.632)
Ir—C	see IRCNIR (2.098, 2.130)
Pt—C		2.130	2.128	0.026	2.106	2.156	4	41, 58
Hg—C	see BODYEY (2.556, 2.577)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.14.7.1 η²-Allenes (R₂CCCR₂)^§
C_α=C_β	(coordinated)	1.403	1.403	0.028	1.375	1.431	5
C_β=C_γ	(free)	1.319	1.321	0.010	1.311	1.327	5
Fe—C_α	see FPCYTP10 (1.982)
—C_β	see FPCYTP10 (1.897)
Rh—C_α	see MARHAA10 (2.177, 2.178)
—C_β	see MARHAA10 (2.032, 2.027)
Pd—C_α	see ALETPD (2.118)
—C_β	see ALETPD (2.068)
Pt—C_α	see MALLPT (2.107)							41
—C_β	see MALLPT (2.049)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.15.1.1 Alkynes (η²-C₂R₂, R = any C)								64
C≡C	all	1.285	1.287	0.030	1.269	1.299	73
	2e donor	1.269	1.271	0.034	1.242	1.284	23
	3e donor	1.285	1.292	0.024	1.268	1.299	15
	4e donor	1.304	1.309	0.027	1.280	1.321	15
V—C	see CPFVLV (2.076)
Cr—C	all PHACCS	1.960	1.960	0.009	1.952	1.969	6
Mn—C	see HDYCMN (1.239)
Co—C	see ACNCOB20 (1.977, 1.981), BETCUY10 (1.847, 1.856)
Cu—C	(3), (1): R = SiMe₃, H	2.019	2.020	0.029	1.994	2.043	5	12
Nb—C	(6, 8), (III): R = Ph	2.082	2.054	0.061	2.041	2.148	8	54
Mo—C	varying electron donation (2–4e): all	2.078	2.072	0.050	2.043	2.143	40	65
	2e donor	2.129	2.131	0.031	2.099	2.148	12
	3e donor	2.071	2.066	0.033	2.053	2.082	12
	4e donor	2.027	2.035	0.028	1.997	2.049	12
Rh—C	: R = Ph, CF₃	2.041	2.045	0.015	2.030	2.051	6
Pd—C	see FMEACA10 (2.040, 2.053)
Ta—C		2.059	2.064	0.024	2.032	2.079	6	54
W—C	varying electron donation (2–4e): all	2.060	2.059	0.036	2.034	2.083	36	65
	2e donor	2.080	2.076	0.041	2.059	2.104	14
	3e donor	2.066	2.066	0.016	2.053	2.078	12
	4e donor	2.025	2.022	0.014	2.013	2.036	10
Re—C		2.043	2.042	0.022	2.029	2.063	6
Ir—C		2.083	2.083	0.041	2.044	2.122	4
Pt—C		2.025	2.029	0.016	2.020	2.037	18	41

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.15.1.2 Alkynes (μ₂-η², η^2′-C₂R₂)^§								64
C≡C		1.353	1.355	0.031	1.337	1.365	29
Co—C		1.954	1.940	0.033	1.930	1.966	47
Ni—C	all FLCPNI	1.910	1.909	0.011	1.901	1.921	4	61
Mo—C		2.171	2.178	0.050	2.137	2.199	32
Rh—C	all CFBYRH	2.054	2.056	0.029	2.026	2.081	4
Ta—C	see ACTHTA (2.217, 2.418)
W—C	all: (show twisting from C_2v → C₂)	2.122	2.099	0.102	2.050	2.214	12
	excluding CAMLAD	2.117	2.099	0.059	2.086	2.158	8

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.15.1.3 Alkynes (μ₂-η¹, η^1′-C₂R₂)^§								64
C≡C		1.315	1.316	0.024	1.301	1.340	14
Co—C	see CAHHAU (2.066)
Ru—C		2.084	2.091	0.016	2.068	2.094	4
Rh—C		2.021	2.001	0.041	1.992	2.064	6
Ir—C		2.112	2.109	0.041	2.082	2.156	8
Pt—C		2.059	2.056	0.009	2.051	2.068	5	41

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.16.1 η³-Allyls (R₂C.CR.CR₂)^§
C¹—C²		1.404	1.404	0.035	1.388	1.421	375
V—C¹	all ALCPPV	2.349	2.352	0.013	2.342	2.357	6
—C²	(2.222, 2.228, 2.245)
Cr—C¹	see CAMWOC (2.171, 2.247)
—C²	(2.193)
Mn—C¹	(6), (I)	2.223	2.227	0.018	2.205	2.233	8
—C²		2.120	2.120	0.004	2.116	2.124	4
Fe—C¹	(5, 6), (0–II)	2.155	2.155	0.044	2.135	2.181	70	60
—C²		2.068	2.070	0.033	2.048	2.092	36
Co—C¹		2.082	2.083	0.029	2.054	2.112	17
—C²		2.000	2.007	0.021	1.985	2.015	9
Ni—C¹	(4, 5), (-)	2.044	2.031	0.057	2.005	2.075	34	66
—C²		1.962	1.967	0.040	1.937	1.995	17
Zr—C¹	(7), (II)	2.472	2.469	0.028	2.444	2.498	8
—C²		2.470	2.476	0.019	2.450	2.485	4
Mo—C¹	(6, 7), (-): most (7), (II)	2.353	2.352	0.057	2.321	2.375	73
—C²		2.244	2.234	0.048	2.214	2.274	37
Ru—C¹	(5, 6), (-): most (6), (II)	2.254	2.247	0.058	2.209	2.293	27
—C²		2.168	2.174	0.041	2.130	2.197	14
Rh—C¹	(4–6), (I, III)	2.191	2.193	0.048	2.151	2.233	24
—C²		2.148	2.138	0.041	2.122	2.159	12
Pd—C¹	: most (4), (II)	2.142	2.133	0.041	2.115	2.172	62
—C²		2.118	2.116	0.034	2.100	2.143	31
W—C¹	(7), (II)	2.303	2.303	0.053	2.256	2.339	16
—C²		2.240	2.229	0.061	2.182	2.293	8
Ir—C¹	(5, 6), (I, III): all	2.212	2.188	0.048	2.175	2.268	8
—C²		2.168	2.165	0.059	2.113	2.225	4
—C¹	(5), (I)	2.174	2.176	0.006	2.167	2.179	4
—C²	(2.100, 2.152)
—C¹	(6), (III)	2.249	2.260	0.039	2.208	2.279	4
—C²	(2.241, 2.178)
Pt—C¹	(4), (II)	2.194	2.191	0.044	2.159	2.242	10	41
—C²		2.170	2.184	0.034	2.138	2.194	5
U—C¹	(7, 9), (IV)	2.670	2.663	0.038	2.640	2.701	10
—C²		2.748	2.781	0.070	2.674	2.806	5

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.17.1 η⁴-Cyclobutadiene (C₄H₄)
C—C		1.423	1.434	0.035	1.409	1.441	16
Fe—C		2.027	2.031	0.026	2.020	2.039	12
—centroid	(1.759, 1.757, 1.763)
Co—C		1.990	1.974	0.034	1.965	2.024	6
—centroid	(1.682, 1.748)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.17.2 η⁴-Cyclobutadienes (C₄R₄, R₄ ≠ H₄)
C—C		1.462	1.464	0.019	1.455	1.472	136
Mn—C	all BUKGET	2.107	2.109	0.019	2.088	2.124	4
—centroid	(1.837)
Fe—C	(5), (0)	2.044	2.039	0.025	2.024	2.066	12	50
—centroid	(1.760, 1.766, 1.779)
Co—C	(5), (I)	1.989	1.987	0.026	1.975	2.003	51
—centroid		1.704	1.694	0.037	1.689	1.706	13
Ni—C	(4, 5), most (II)	2.027	2.025	0.036	2.001	2.060	16	67
—centroid		1.742	1.740	0.018	1.727	1.761	4
Mo—C	(6), (0, I)	2.280	2.270	0.041	2.249	2.299	16
—centroid		2.032	2.033	0.036	1.998	2.065	4
—C	(6), (0)	2.308	2.298	0.040	2.276	2.338	8
—centroid	(2.060, 2.066)
—C	(6), (I)	2.253	2.252	0.018	2.240	2.269	8
—centroid	(1.995, 2.006)
Ru—C	(5, 6), (0, II)	2.224	2.184	0.086	2.168	2.312	8
—centroid	(2.006, 1.926)
—C	(5), (0): all COCLEL	2.261	2.256	0.116	2.159	2.368	4
—C	(6), (II): all CIMVID	2.188	2.184	0.015	2.176	2.204	4
Rh—C	(5), (I)	2.114	2.105	0.025	2.102	2.120	8
—centroid	(1.850, 1.829)
Pd—C	(4, 5), (II)	2.148	2.135	0.065	2.106	2.160	16
—centroid		1.887	1.873	0.042	1.857	1.932	4
—C	(5), (II)	2.130	2.135	0.027	2.106	2.145	12
Pt—C	all CBFPPT10	2.219	2.214	0.096	2.129	2.314	4
—centroid	(1.963)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.17.3 η⁴-1,3-Butadienes (R₂C.CR.CR.CR₂)^§								68
C¹—C²		1.420	1.420	0.021	1.409	1.433	213
C²—C²		1.405	1.404	0.023	1.392	1.416	108
Cr—C¹		2.332	2.349	0.046	2.277	2.370	6
—C²		2.147	2.134	0.043	2.110	2.200	6
Mn—C¹	(5), (0)	2.134	2.135	0.007	2.128	2.141	8
—C²		2.080	2.071	0.025	2.066	2.106	8
Fe—C¹		2.130	2.128	0.029	2.111	2.148	113	60
—C²		2.059	2.058	0.018	2.050	2.068	113
Co—C¹	(5, 6), (0, I)	2.089	2.102	0.045	2.061	2.125	12
—C²		2.015	2.003	0.033	1.994	2.018	12
—C¹	excluding 2 < 2.015	2.105	2.106	0.025	2.095	2.132	10
—C²	excluding 2 > 2.075	2.001	1.998	0.012	1.993	2.013	10
Ni—C¹	see BUJFUH (2.360, 2.106)
—C²	see BUJFUH (2.074, 2.018)
Zr—C¹	(7, 8), (-): all	2.402	2.323	0.162	2.305	2.526	14	69
—C²		2.522	2.549	0.120	2.397	2.582	14
—C¹	structures with Zr—C¹ < Zr—C²	2.314	2.311	0.021	2.298	2.326	10
—C²		2.582	2.563	0.078	2.542	2.624	10
Mo—C¹	(5–7), (-)	2.356	2.364	0.052	2.331	2.378	20
—C²		2.280	2.280	0.038	2.251	2.309	20
Ru—C¹	(5, 6), (0, II)	2.254	2.246	0.060	2.223	2.267	17
—C²		2.181	2.173	0.050	2.155	2.194	17
—C¹	excluding 2 > 2.385	2.236	2.233	0.033	2.218	2.265	15
—C²	excluding 2 > 2.29	2.165	2.169	0.025	2.155	2.180	15
Rh—C¹		2.214	2.224	0.047	2.165	2.252	4
—C²		2.177	2.198	0.043	2.134	2.199	4
Hf—C¹	(6), (0): all	2.369	2.368	0.019	2.350	2.387	8	69
—C²		2.400	2.400	0.006	2.395	2.407	8
W—C¹	see HPMXCW10 (2.453, 2.460)
—C²	see HPMXCW10 (2.335, 2.263)
Re—C¹	see BIBJEB (2.310, 2.277)
—C²	see BIBJEB (2.276, 2.258)
Os—C¹	see OXBUDC10 (2.243, 2.300)
—C²	see OXBUDC10 (2.198, 2.240)
Ir—C¹	see BUHIPI (2.277, 2.162); CBUTIR (2.186)
—C²	see BUHIPI (2.141, 2.202); CBUTIR (2.153)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.17.4 η⁴-1,5-Cyclooctadiene (1,5-cod)								62
	(see 3.14.4)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.17.5 η⁴-Norbornadiene (nbd)								62
	(see 3.14.4)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.18.1 η⁵-Cyclopentadienyl (C₅H₅)
C—C		1.397	1.398	0.028	1.380	1.415	6804
Sc—C	all TCYPSC10	2.494	2.499	0.023	2.473	2.513	10
—centroid	(2.189, 2.194)
Ti—C		2.374	2.375	0.031	2.354	2.396	832
—centroid		2.062	2.061	0.026	2.044	2.082	170
V—C		2.281	2.281	0.026	2.260	2.301	226
—centroid		1.952	1.950	0.020	1.938	1.970	46
Cr—C		2.225	2.226	0.033	2.197	2.250	295
—centroid		1.876	1.882	0.029	1.847	1.898	61
Mn—C	: all	2.166	2.149	0.094	2.127	2.164	321	30
—centroid	: all	1.824	1.786	0.132	1.775	1.798	67	30
—C	(-), (-): low spin	2.143	2.146	0.026	2.125	2.161	300
—centroid	: low spin	1.783	1.784	0.018	1.774	1.794	61
—C	: Mn^II, high spin	2.511	2.499	0.052	2.479	2.541	20
—centroid		2.237	2.229	0.051	2.196	2.262	6
Fe—C		2.080	2.088	0.035	2.052	2.106	1309	60
—centroid		1.706	1.721	0.039	1.662	1.735	265
Co—C		2.068	2.066	0.031	2.045	2.089	740
—centroid		1.696	1.692	0.029	1.676	1.716	152
Ni—C		2.116	2.113	0.033	2.093	2.138	315	70
—centroid		1.748	1.750	0.025	1.734	1.762	65
Cu—C	all TPCYCU	2.211	2.205	0.018	2.195	2.231	5
—centroid	(1.864)
Zn—C		2.348	2.332	0.080	2.299	2.440	15
—centroid		2.044	2.038	0.027	2.021	2.072	4
Y—C		2.649	2.646	0.040	2.626	2.668	75
—centroid		2.382	2.379	0.041	2.356	2.386	15
Zr—C		2.529	2.529	0.031	2.510	2.546	649	71
—centroid		2.236	2.233	0.023	2.220	2.251	132
—C	excluding BOYLUW	2.528	2.528	0.026	2.510	2.545	638
—centroid	excluding BOYLUW	2.235	2.232	0.022	2.220	2.250	131
Nb—C		2.408	2.406	0.037	2.385	2.435	353	54
—centroid		2.093	2.093	0.029	2.075	2.110	71
Mo—C		2.336	2.338	0.042	2.304	2.368	1363
—centroid		2.011	2.010	0.033	1.992	2.026	278
Ru—C		2.236	2.240	0.041	2.204	2.267	284
—centroid		1.892	1.898	0.042	1.857	1.929	58
Rh—C		2.239	2.236	0.037	2.218	2.264	256
—centroid		1.895	1.898	0.032	1.879	1.914	53
Pd—C	all BUPTEL	2.344	2.350	0.050	2.303	2.381	5
—centroid	(2.015)
Pr—C	all CXINPR10	2.778	2.765	0.026	2.760	2.801	15	1, 21
—centroid	(2.526, 2.527, 2.526)
Gd—C	all CPTHGD10	2.738	2.744	0.025	2.722	2.747	15	1, 21
—centroid	(2.472, 2.490, 2.494)
Er—C	all BOBWAQ	2.667	2.665	0.005	2.663	2.671	5	1, 21
—centroid	(2.391)
Yb—C	(8, 10), (-)	2.657	2.642	0.047	2.621	2.693	25	1, 21
—centroid		2.383	2.383	0.043	2.340	2.426	5
Lu—C	all OHCPLU	2.600	2.599	0.018	2.584	2.615	10	1, 21
—centroid	(2.309, 2.316)
Hf—C		2.505	2.507	0.020	2.494	2.520	60	71
—centroid		2.208	2.211	0.015	2.195	2.220	12
Ta—C		2.392	2.395	0.036	2.373	2.411	60	54
—centroid		2.072	2.068	0.031	2.040	2.101	12
W—C		2.337	2.337	0.042	2.307	2.364	566
—centroid		2.005	2.007	0.035	1.985	2.026	114
Re—C	(6–8), (-)	2.296	2.293	0.039	2.270	2.327	103
—centroid		1.959	1.958	0.026	1.946	1.980	21
Os—C	(6), (-)	2.235	2.233	0.032	2.220	2.262	10
—centroid	(1.916, 1.856)
Ir—C		2.263	2.273	0.030	2.244	2.281	35
—centroid		1.922	1.917	0.012	1.913	1.936	7
U—C		2.759	2.765	0.031	2.740	2.776	63
—centroid		2.493	2.491	0.015	2.483	2.506	13

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.18.2 η⁵-Pentamethylcyclopentadienyl (C₅Me₅)
C—C(ring)		1.417	1.418	0.024	1.404	1.433	1164
C—C(Me)		1.512	1.509	0.025	1.497	1.523	1239
Ti—C		2.403	2.394	0.028	2.384	2.418	61
—centroid		2.086	2.071	0.027	2.064	2.116	13
V—C		2.334	2.339	0.054	2.283	2.357	30
—centroid		2.009	2.010	0.047	1.979	2.051	6
Cr—C		2.209	2.204	0.017	2.197	2.232	10
—centroid	(1.847, 1.858)
Mn—C		2.146	2.147	0.027	2.126	2.158	25
—centroid		1.777	1.777	0.027	1.755	1.800	5
Fe—C		2.116	2.115	0.026	2.095	2.136	25
—centroid		1.739	1.730	0.026	1.715	1.766	5
Co—C		2.098	2.099	0.035	2.078	2.118	155
—centroid		1.717	1.722	0.035	1.705	1.735	31
Ni—C	all BINFUZ	2.102	2.120	0.027	2.073	2.122	5
—centroid	(1.725)
Cu—C	all BUPWOY10	2.271	2.271	0.051	2.223	2.319	5
—centroid	(1.920)
Zr—C		2.545	2.545	0.031	2.522	2.562	55
—centroid		2.244	2.244	0.023	2.232	2.253	11
Mo—C		2.365	2.364	0.047	2.328	2.407	78
—centroid		2.034	2.032	0.029	2.010	2.058	16
Ru—C	all COPKEX	2.268	2.269	0.012	2.258	2.279	5
—centroid	(1.917)
Rh—C		2.217	2.217	0.057	2.168	2.254	367
—centroid		1.856	1.870	0.060	1.795	1.908	75
Pd—C	all BUSHEC	2.341	2.351	0.073	2.280	2.397	5
—centroid	(2.003)
Sm—C	(8), (II, III): all	2.809	2.808	0.063	2.745	2.864	40	1, 30, 60
—centroid		2.537	2.535	0.067	2.472	2.601	8
—C	(8), (II): all CALCEX	2.864	2.863	0.030	2.836	2.889	20
—centroid		2.599	2.601	0.006	2.593	2.604	4
—C	(8), (III): all BUFNOF	2.754	2.747	0.031	2.727	2.786	20
—centroid		2.475	2.475	0.005	2.470	2.479	4
Eu—C	all CIFCAV	2.815	2.808	0.019	2.799	2.834	5	1, 60
—centroid	(2.550)
Yb—C	: all	2.608	2.597	0.052	2.576	2.631	127	1, 60
—centroid		2.320	2.324	0.053	2.283	2.340	27
—C	excluding BIKTIY	2.597	2.592	0.035	2.574	2.619	117
—centroid		2.308	2.303	0.033	2.283	2.335	25
Lu—C	all CIXTUY	2.710	2.731	0.090	2.623	2.780	10	1, 60
—centroid	(2.360, 2.493)
Ta—C		2.439	2.435	0.039	2.404	2.469	53	54
—centroid		2.122	2.118	0.029	2.095	2.137	11
Re—C		2.297	2.289	0.041	2.266	2.336	30
—centroid		1.956	1.976	0.034	1.913	1.979	6
Os—C	all BIJKOU	2.244	2.218	0.043	2.211	2.291	5
—centroid	(1.887)
Ir—C	(6, 7), (III, V): all	2.158	2.157	0.043	2.139	2.185	56
—centroid		1.792	1.783	0.049	1.760	1.808	12
—C	(6), (III)	2.151	2.155	0.024	2.134	2.170	46
—centroid		1.773	1.778	0.025	1.753	1.791	10
—C	(7), (V): all CECKOK	2.245	2.249	0.018	2.227	2.258	10
—centroid	(1.875, 1.893)
Th—C		2.817	2.822	0.026	2.793	2.838	15
—centroid	(2.536, 2.547, 2.573)
U—C		2.752	2.752	0.033	2.724	2.776	58
—centroid		2.479	2.484	0.022	2.460	2.493	12

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.18.3 η⁵-Indenyl (C₉H₇)^§
C^l—C²		1.407	1.410	0.028	1.400	1.421	34
C²—C³		1.444	1.449	0.020	1.428	1.458	34
C³—C^3′		1.432	1.427	0.017	1.420	1.441	17
Cr—C¹	see BABFOZ (2.176)
—C²	(2.184, 2.197)
—C³	(2.288, 2.301)
—centroid	(1.869)
Mo—C¹	(6), (-) (2.341, 2.346, 2.350)
—C²		2.341	2.354	0.065	2.278	2.392	6
—C³		2.409	2.430	0.041	2.370	2.439	6
—centroid	(2.051, 2.034, 2.025)
Rh—C¹	(5, 6), (-)	2.223	2.221	0.019	2.213	2.236	9
—C²		2.226	2.224	0.034	2.200	2.243	18
—C³		2.399	2.401	0.051	2.364	2.426	18
—centroid		1.948	1.954	0.037	1.921	1.961	9
Ce—C¹	all INDCEP (2.748, 2.757, 2.782)							60
—C²		2.805	2.794	0.043	2.766	2.849	6
—C³		2.961	2.964	0.036	2.933	2.988	6
—centroid	(2.587, 2.591, 2.606)
U—C¹	see CAFNOM (2.709)
—C²	(2.710, 2.720)
—C³	(2.769, 2.813)
—centroid	(2.455)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.18.4 η⁵-Dienyls (C₅H₇ and derivatives)^§								72, 73
C¹—C²		1.408	1.403	0.026	1.391	1.422	24
C²—C³		1.415	1.414	0.021	1.399	1.427	24
V—C¹	all COGXOL	2.179	2.180	0.017	2.162	2.195	4
—C²		2.231	2.233	0.011	2.219	2.240	4
—C³	(2.236, 2.236)
Cr—C¹	see COGXUR (2.159, 2.174)
—C²	see COGXUR (2.147, 2.177)
—C³	see COGXUR (2.166)
Mn—C¹	see OAZPMN10 (2.209, 2.298)
—C²	see OAZPMN10 (2.137, 2.143)
—C³	see OAZPMN10 (2.146)
Fe—C¹	all MEPEFE10	2.108	2.109	0.016	2.094	2.122	4
—C²		2.073	2.072	0.015	2.060	2.088	4
—C³	(2.081, 2.086)
Co—C¹	(5), (I)	2.135	2.136	0.010	2.125	2.143	4
—C²		2.078	2.075	0.015	2.066	2.094	4
—C³	(2.060, 2.087)
Zr—C¹	see HMPEZR (2.432, 2.446)
—C²	see HMPEZR (2.428, 2.438)
—C³	see HMPEZR (2.469)
Ru—C¹	(6), (II)	2.169	2.171	0.016	2.154	2.181	6
—C²		2.168	2.167	0.028	2.149	2.194	6
—C³	(2.177, 2.257, 2.258)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.19.1 η⁶-Benzene (C₆H₆)								74
C—C		1.399	1.398	0.023	1.385	1.413	105
Ti—C	all BELGOO10	2.228	2.225	0.009	2.220	2.236	12
—centroid	(1.736, 1.742)
Cr—C	(6), (0, I)	2.180	2.176	0.044	2.147	2.219	20
—centroid		1.676	1.691	0.056	1.618	1.725	5
Fe—C	all BUVLEJ	2.059	2.063	0.025	2.035	2.077	12
—centroid	(1.542, 1.548)
Co—C	see BNZCTC (2.123)
—centroid	(1.603)
Mo—C	(7), (II)	2.279	2.273	0.051	2.247	2.315	18
—centroid	(1.767, 1.805, 1.819)
Ru—C	(6), (-): all	2.187	2.168	0.042	2.154	2.227	21
—centroid		1.674	1.659	0.043	1.644	1.720	4
Re—C	(5, 6), (-)	2.217	2.214	0.034	2.186	2.249	30
—centroid		1.725	1.725	0.026	1.703	1.747	5
Os—C	(6), (-)	2.166	2.165	0.055	2.135	2.191	30
—centroid		1.657	1.635	0.057	1.620	1.705	5

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.19.2 η⁶-Arenes (C₆R₆, R = any C, H)								74
C—C	(intra-ring)	1.411	1.411	0.021	1.398	1.423	818
Ti—C	(6, 7), (0, II): all	2.330	2.247	0.125	2.240	2.479	18	30
Ti—C	(6), (0)	2.245	2.244	0.010	2.238	2.248	12
—centroid	(1.742, 1.744)
—C	(7), (II)	2.498	2.502	0.037	2.465	2.530	6
—centroid	(2.055)
V—C	all DFBENV	2.192	2.192	0.010	2.181	2.203	6
—centroid	(1.692)
Cr—C	(6), (0, I)	2.216	2.216	0.045	2.196	2.239	412
—centroid		1.710	1.718	0.046	1.699	1.733	73
Fe—C	(5, 6), (0, II)	2.101	2.097	0.036	2.078	2.114	82
—centroid		1.563	1.549	0.032	1.539	1.586	14
Co—C	(5, 6), (I, II)	2.167	2.131	0.060	2.122	2.228	13
—centroid	(1.602, 1.766, 1.628)
Ni—C	(5), (II)	2.209	2.216	0.041	2.170	2.238	10	75
—centroid	(1.713, 1.699)
Zr—C	all CLZRAL	2.590	2.592	0.030	2.558	2.619	9
—centroid	(2.164, 2.178)
Nb—C		2.404	2.457	0.096	2.283	2.479	28	30
—centroid		1.939	1.938	0.005	1.935	1.944	5
—C	long > 2.425	2.473	2.474	0.016	2.459	2.484	18
—C	short < 2.352	2.280	2.282	0.019	2.264	2.289	10
Mo—C	(6, 7), (0–III)	2.320	2.322	0.057	2.274	2.370	93
—centroid		1.841	1.838	0.061	1.794	1.904	16
Ru—C	(5, 6), (0, II)	2.247	2.235	0.051	2.212	2.264	78
—centroid		1.745	1.727	0.059	1.697	1.767	13
—C	(5, 6), (0, II): excluding BENLOV	2.238	2.230	0.040	2.210	2.258	72
—centroid		1.733	1.727	0.042	1.695	1.757	12
Rh—C	(5, 6), (-)	2.327	2.315	0.052	2.291	2.363	22
—centroid		1.845	1.864	0.051	1.793	1.878	4
Hf—C	all SNTLHF	2.481	2.493	0.041	2.433	2.519	6
—centroid	(2.041)
W—C	(6, 7), (0, II)	2.291	2.293	0.038	2.269	2.309	46
—centroid		1.803	1.805	0.043	1.768	1.821	8
Re—C	all CIZNUU	2.327	2.328	0.005	2.323	2.331	6
—centroid	(1.863)
Os—C	(4, 6), (-)	2.213	2.198	0.053	2.181	2.230	18
—centroid	(1.638, 1.718, 1.719)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.20.1 η⁷-Tropylium (C₇H₇) and derivatives
C—C		1.408	1.409	0.022	1.393	1.418	126
Ti—C	(7), (-)	2.228	2.236	0.020	2.204	2.242	21
—centroid	(1.484, 1.544, 1.569)
Cr—C	(7), (-)	2.220	2.210	0.043	2.189	2.241	14
—centroid	(1.445, 1.571)
Mo—C	(7), (-)	2.280	2.278	0.032	2.256	2.300	105
—centroid		1.607	1.596	0.035	1.577	1.649	15

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.20.2 η⁸-Cyclooctatetraene (C₈H₈) and derivatives
C—C		1.397	1.399	0.027	1.385	1.409	114
Ti—C	(7), (III, IV)	2.349	2.373	0.043	2.319	2.384	32
—centroid		1.471	1.490	0.063	1.409	1.524	5
—C	(7), (III)	2.368	2.378	0.027	2.338	2.388	24	30
—centroid		1.495	1.504	0.040	1.453	1.527	4
—C	short < 2.35	2.329	2.328	0.009	2.321	2.336	7
—C	long > 2.37	2.384	2.383	0.009	2.378	2.391	17
—C	(7), (IV): all CEXTII	2.291	2.293	0.023	2.270	2.311	8
—centroid	(1.377)
V—C	all BUPLAZ10	2.282	2.281	0.039	2.257	2.293	8
—centroid	(1.376)
Zr—C	(7), (II, IV)	2.461	2.459	0.017	2.449	2.474	16
—centroid	(1.685, 1.650)
Ce—C	all COCTCE	2.710	2.709	0.015	2.700	2.720	8	1
—centroid	(2.007)
Th—C	(8), (IV)	2.712	2.710	0.016	2.701	2.724	16
—centroid	(2.029, 2.003)
U—C	(8), (IV)	2.653	2.648	0.019	2.637	2.667	48
—centroid		1.917	1.919	0.005	1.913	1.921	5

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.21.1 Carbaboranes (see also 2.2.1)								29
Ti—C	see CEXTII (2.265, 2.340)
V—C	see BUPLAZ10 (2.191, 2.269)
Cr—C		2.197	2.188	0.065	2.140	2.265	6
Mn—C	see PMCMNB (2.043, 2.047)
Fe—C		2.073	2.069	0.070	2.041	2.108	62
Co—C		2.046	2.049	0.055	2.013	2.078	76
Ni—C		2.087	2.071	0.071	2.045	2.145	15
Ru—C	see RUCABO (2.097, 2.185)
Rh—C		2.239	2.237	0.065	2.187	2.287	26
Pd—C	see BICPDB (2.599), MPPDBN (2.414, 2.492)
W—C		2.420	2.431	0.044	2.374	2.455	4
Re—C	see CSCREC (2.310, 2.316)
Pt—C	(range 2.142–2.768)	2.441	2.447	0.199	2.277	2.591	12
Hg—C		2.101	2.106	0.013	2.089	2.110	5

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.21.2 Borylenes etc. (see also 2.3.1)								31–33
V—C	see BOKXEE (2.297)
Mn—C		2.197	2.188	0.037	2.167	2.234	10
Fe—C		2.118	2.098	0.050	2.086	2.150	16
Co—C		2.062	2.031	0.061	2.025	2.091	19
Ni—C	: all	2.120	2.091	0.085	2.053	2.193	9
	: excluding FMBCNI	2.080	2.076	0.036	2.044	2.144	7

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
3.22.1 η²-CO₂ (see also 5.25.2)
(None)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
3.22.2 η²-CS₂ (see also 9.17.1)
C=S	(coordinated)	1.665	1.671	0.018	1.656	1.676	6
C=S	(free)	1.613	1.616	0.006	1.607	1.618	6
V—C	see CPCDSV (2.075, 2.089)
Fe—C	see SPHFEC10 (1.983)
Co—C	see TPHCOA (1.882)
Ni—C	see COGWOK (1.858)
Nb—C	see CPSNBA (2.206)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.1.1.1 Nitride (terminal N)								76
Cr—N	see BOZYIY (1.562)
Mn—N	see ZEGGUN (1.512)
Mo—N	(5, 6), (VI)	1.636	1.636	0.006	1.630	1.641	4	77
Tc—N	see BAGWAH (1.604), CETKUH (1.629)
Re—N	(5, 6), (V): see BOCLOU (1.660), NEPPRE (1.788), NETPRE (1.602), NREDTC10 (1.656)

Bond	Substructure (coordination number, oxidation state, comment)	Note^†
4.1.1.2 Nitride (μ-N)		78
Mo—N (μ₂)	see BUPZIV (1.662, 2.150; 1.643, 2.167)
Ru—N (μ₂)	see CEPBII (1.742)
W—N (μ₂)	see CAWGAI (1.740, 2.661)
Mo—N (μ₃)	see BAXFEL (range 1.900–1.979)
Ru—N (μ₄)	see BITRAX (1.913, 1.943, 2.103, 2.114)
Rh—N (μ₆)	see BOZBOH (range 2.124–2.137)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.2.1.1 Nitrenes/imides (terminal NR, R = any C)								79
N—C		1.415	1.394	0.047	1.387	1.457	51
V—N	see CIZTEK (1.730)
Nb—N	see CAHJIE (1.783), COBLIO (1.733)
Mo—N	(5–7), (V, VI):	1.729	1.728	0.019	1.719	1.733	20
	: excluding 1 with Mo—N—C 139.4°	1.726	1.728	0.013	1.718	1.732	19
Ta—N	see BEHHIF (1.765), COBDUS (1.762)
W—N	(4–6), (V, VI)	1.738	1.739	0.026	1.725	1.754	13
Re—N	(6), (V–VII)	1.701	1.694	0.019	1.688	1.709	9
Os—N	see ADOOSA (1.697), ADOOSB (1.706, 1.720)
U—N	see CESVUR (2.063)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.2.1.2 Nitrenes/imides (μ₂-NR)
N—C	R = C(sp²)	1.392	1.395	0.021	1.374	1.409	7
	R = ^tBu	1.483	1.484	0.007	1.475	1.488	4
Ti—N	see BIJJUZ10 (1.920), BUIMWB (1.921, 1.926)
Zr—N	see TBIAZR (2.060, 2.071)
Nb—N	all BENRAN	2.043	2.042	0.011	2.033	2.053	4
Mo—N	(6), (-): excluding BUMEMO (1.819, 2.322)	1.970	1.973	0.010	1.958	1.978	6
W—N	see BUIMWA (1.841, 2.288), CACRIH (1.891, 2.312)

Bond	Substructure (coordination number, oxidation state, comment)	Note^†
4.3.1.1 Alkylideneamido (N=CR₂, linear)		80
N—C	(1.258, 1.275, 1.259)
Zr—N	see CEFSIP (2.013)
Mo—N	see BUDZEF (1.878), CPBUMO (1.892)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.4.1 Nitriles (NCR, R = any C)
N—C		1.133	1.134	0.020	1.121	1.144	102
Ti—N	see ECYFTI (2.245)
V—N	see ACNCVO (2.097), BZTCOV (2.124), COPHAV (2.107)
Fe—N	(5, 6), (II, III): all	2.029	1.976	0.153	1.928	2.161	7
	(5, 6), (II): low spin	1.946	1.966	0.041	1.905	1.977	5
Co—N	(4, 5), (0, I): all	1.971	1.951	0.068	1.920	2.041	4
Ni—N	see BCETPN (2.082), CARWAT (2.109), EFUMNI (1.873)
Cu—N	(4–6, ^‡), (I, II): all	2.121	2.005	0.249	1.968	2.321	11
	(4, ^‡), (I, II)	1.983	1.975	0.042	1.960	2.036	8
Nb—N	(6), (IV, V): all	2.322	2.303	0.083	2.254	2.414	8	81
	(6), (IV, V)	2.282	2.292	0.042	2.238	2.315	6	44
Mo—N	(5–7), (II, VI)	2.147	2.144	0.041	2.125	2.177	9	44
Tc—N	see CETKUH (2.492)
Ru—N	(5, 6, ^‡), (0, II, IV): all	2.090	2.108	0.037	2.052	2.118	5
Rh—N	(4–6), (I, II)	2.139	2.152	0.091	2.052	2.232	11	30
	(4, 5), (I)	2.050	2.052	0.006	2.045	2.056	5
	(6), (II)	2.214	2.225	0.043	2.166	2.252	6	82
Pd—N	see CAKNIL10 (2.063)
Cd—N	see CDCYAC (2.372)
Re—N	(6), (I, II): all	2.107	2.125	0.040	2.065	2.137	13
Os—N	(6, ^‡), (-): all	2.098	2.096	0.028	2.084	2.124	10
Ir—N	see BESSEX (2.054), CEYBEN (2.044), IRTCPP10 (2.024)
Pt—N	(4, 5), (I, II): all	2.003	1.982	0.048	1.978	2.036	8
	(4), (II)	1.980	1.979	0.019	1.971	1.990	6
U—N	see CIHLIO (2.604, 2.580)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.4.2 Cyano (μ₂-CN)^§ (see also 3.5.1.2)
Cr—N	see CYCRTF (1.975, 1.975, 1.994)
Mn—N	see CAZJAO10 (2.165), CAZJES10 (2.186)
Cu—N	(4–6), (II): all	2.051	2.001	0.135	1.956	2.103	11
	: excluding 2 > 2.3	1.994	1.995	0.052	1.955	2.022	9
Pd—N	see BUSRIQ (2.067)
Cd—N	(4, 6), (II)	2.361	2.352	0.042	2.327	2.403	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.5.1.1 Isocyanate (terminal NCO) (see also 5.25.3.1)								83
N—C		1.141	1.148	0.020	1.125	1.156	16
C—O		1.202	1.197	0.016	1.189	1.215	16
Ti—N	see CPTICN10 (2.007, 2.018)
Cr—N	see CPNOCC10 (1.980)
Mn—N	see CENRES (1.919, 1.934), TRENCM (2.051)
Co—N	see CNTPCP (1.949), CYZNIC10 (2.055)
Cu—N	(4–6, ^‡), (II): all	1.935	1.926	0.049	1.897	1.954	8

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.5.1.2 Isocyanate (μ₂-NCO) (see also 5.25.3.2)^§
N—C	(1.152, 1.154)
C—O	(1.182, 1.216)
Cu—N	see CNPRCV (1.946), ICNPCU10 (1.952)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.5.1.3 Isocyanate (μ₂-N,N-NCO)
N—C	(1.168)
C—O	(1.173)
Cu—N	see COVYIV (2.266, 2.023)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.5.2.1 N-Isothiocyanates (terminal NCS) (see also 9.3.1.1)								84
N—C		1.149	1.150	0.017	1.141	1.159	230
C—S		1.620	1.619	0.022	1.608	1.632	231
Ti—N	see CPITTI (2.021)
Cr—N	(6), (III): excluding CEFMAB (2.250)	1.999	1.998	0.016	1.984	2.012	12	85
Mn—N	(5–7), (II, III)	2.166	2.167	0.051	2.128	2.196	13
	(6), (II): Mn—N—C > 152°	2.141	2.146	0.027	2.107	2.167	7
Fe—N	(5–7), (II, III): all	2.063	2.095	0.084	1.982	2.133	12
	(6, 7), (high spin II)	2.108	2.106	0.031	2.088	2.139	7
Co—N	(4–6), (II, III)	2.000	1.992	0.076	1.927	2.072	42	30
	(4), (II)	1.956	1.957	0.010	1.948	1.964	8
	(5), (II)	2.034	2.028	0.050	2.004	2.064	6
	(6), (II)	2.073	2.075	0.029	2.064	2.099	15
	(6), (III): excluding ITDASC (2.117)	1.911	1.910	0.015	1.900	1.922	12
Ni—N	(4–6), (II): all	2.035	2.064	0.079	2.026	2.077	44	30
	(4)	1.855	1.835	0.046	1.827	1.886	6
	(6)	2.064	2.068	0.027	2.054	2.079	36
Cu—N	(4–6), (II): all	2.045	1.970	0.165	1.945	2.101	25	86
	(5), (II): (Cu—N—C > 152°)	2.013	1.968	0.102	1.946	2.073	21	86
Zn—N	(4–6), (II): all	1.988	1.945	0.081	1.923	2.083	8	30
	(4), (II)	1.931	1.929	0.013	1.919	1.945	5
Zr—N	see TCBPZR (2.183)
Nb—N	(6, 8), (IV, V)	2.132	2.130	0.035	2.100	2.166	4
Mo—N	(6, 7), (V, VI)	2.148	2.166	0.077	2.065	2.183	11	81, 87
Tc—N	(6), (II, III, V)	2.049	2.046	0.011	2.043	2.057	6
Pd—N	(4), (II)	2.023	2.025	0.028	2.011	2.043	9
Cd—N	(5, 6), (II)	2.245	2.241	0.047	2.212	2.259	7
Dy—N	see CIKTOF (2.433)
Re—N	(6), (III, V)	2.024	2.018	0.023	2.009	2.038	7
Pt—N	see PEYEPP (2.025)
Th—N	(8), (IV)	2.496	2.496	0.024	2.474	2.513	9
U—N	(8, 9, 11), (IV)	2.439	2.448	0.046	2.407	2.467	18

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.5.2.2 Isothiocyanates (μ₂-NCS) (see also 9.3.1.2)^§
N—C		1.144	1.149	0.020	1.129	1.160	24
C—S		1.642	1.643	0.017	1.632	1.650	24
Mn—N	see TCMNET10 (2.143)
Co—N	(6), (II)	2.111	2.118	0.020	2.091	2.128	5
Ni—N	see TCYENI10 (2.031)
Cu—N	(4, 5), (II): excluding COHHIQ (2.205)	1.962	1.951	0.031	1.939	1.999	6
Ag—N	see CENSUJ (2.281), CENTAQ (2.332)
Cd—N	(5, 6), (II)	2.287	2.294	0.019	2.267	2.300	4
Pt—N	see TPPTCP01 (1.966)
Hg—N	see TCHXPH10 (2.517), TCPPHG10 (2.405, 2.735)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.6.1.1 Dinitrogen (η¹-N₂)								88
N—N		1.100	1.110	0.048	1.074	1.124	18
Cr—N	see CAVMOB (1.957)
Fe—N	see PHSNFE (1.866)
Co—N	see CARKIP (1.814), PPHCHN10 (1.783, 1.832)
Zr—N	see MCPNZR (2.187, 2.188)
Mo—N	(6), (0, I)	2.013	1.996	0.056	1.971	2.072	4	89
Ru—N	see ENAZPU10 (1.893)
Rh—N	see HNBPRH10 (1.970)
W—N	see BUYBUS (2.038)
Re—N	see BIBJAX (1.956), BUKMID (2.055), CNMPRE (1.966)							90
Os—N	see CAJCEV (1.909)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.6.1.2 Dinitrogen (μ₂-η¹, η^1′-N₂)^§
N—N	excluding BEJGAY (1.282), IMNPTA10 (1.298)	1.155	1.155	0.020	1.137	1.174	5
Ti—N	(7), (II): all NPMCTI	2.017	2.014	0.012	2.007	2.029	4
Fe—N	see BALWUG (1.877)
Zr—N	see MCPNZR (2.087, 2.075)
Mo—N	see NMSPEM (2.042)
Ta—N	see BEJGAY (1.796), IMNPTA10 (1.837)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.7.1 Diazoniums/Diazenido (η¹-NNR)								80
N—N		1.219	1.224	0.032	1.210	1.236	14
N—C		1.428	1.427	0.024	1.414	1.438	14
Mn—N	see FTLAMN (1.696)
Mo—N	(6, 7), (0–VI): all Mo—N—N > 160°, N—N—C < 130°	1.806	1.816	0.028	1.778	1.832	8
Ru—N	see CTZPRU (1.795)
Rh—N	see CPZRHF10 (1.961)
W—N	see CPCMZW (1.850)
Os—N	see HPZPOS (1.867)
Ir—N	see PAZMPI (1.834)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.7.2 Diazoalkanes (η¹-NNCR₂)
N—N	all bent N—N—C	1.319	1.312	0.027	1.300	1.346	8
N—C		1.309	1.311	0.015	1.294	1.320	8
Mn—N	see AZMLMN (1.796)
Mo—N	see BAMTAK10 (1.759, 1.782), CIYBAN (1.797)
W—N	see AZPPBW10 (1.723), BCAZWB (1.784), CIXJIC (1.776)
Ir—N	see PCLPIR (1.825)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.8.1.1 Azido (η¹-N₃)^§								84
(M)N—N		1.180	1.183	0.020	1.175	1.193	37
N—N		1.149	1.150	0.020	1.141	1.163	37
Ti—N	see AZCPTI (2.025)
Mn—N	see MNACAZ30 (2.244)
Co—N	(5, 6), (I, III)	1.991	1.967	0.047	1.952	2.030	7
Cu—N	(4–6), (I, II): all	2.012	1.969	0.088	1.962	2.040	15
	(4–6), (II): excluding 3 > 2.16	1.966	1.964	0.024	1.948	1.980	11
Mo—N	(5, 6), (II, VI): all	2.095	2.062	0.078	2.026	2.175	10	30
	(5, 6), (VI)	2.037	2.036	0.025	2.019	2.054	6
	(6), (II): all BUNZOZ	2.182	2.175	0.021	2.167	2.203	4
Ru—N	see ENAZPU10 (2.122)
Pd—N	see AZENPD10 (2.077), BEJJAB (2.044)
U—N	see BOPTEF (2.382)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.8.1.2 Azido (μ₂-N¹,N¹-N₃)^§
N¹—N²		1.210	1.202	0.025	1.195	1.220	11
N²—N³	excluding 2 > 1.25	1.135	1.136	0.015	1.127	1.146	9
Cu—N	(4–6), (II): excluding 1 > 2.4	2.014	2.018	0.040	1.986	2.034	15
Zr—N	see BAXFOV (2.202, 2.204)
Rh—N	see AFMZRH (2.133, 2.105)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.8.1.3 Azido (μ₂-N¹,N³-N₃)^§
N—N		1.173	1.171	0.015	1.167	1.183	8
Ni—N	see ZTANPB (2.196, 2.069)
Cu—N	see BUVNIP (2.456, 1.979), MDNCAZ10 (2.252, 1.985), TTZZCU10 (2.013, 1.994)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.9.1.1 Nitrosyl (terminal NO)								78, 80
N—O	all	1.172	1.173	0.036	1.155	1.194	211	91
	M—N—O > 150°	1.176	1.175	0.030	1.156	1.194	197
	M—N—O < 140°	1.114	1.125	0.057	1.064	1.164	10
V—N	see BEYFEQ (1.809), BIVGAO (1.760)
Cr—N	(4, 6, 7): (Cr—N—O 166–180°)	1.684	1.680	0.022	1.675	1.694	16
Mn—N	(5, 6): (Mn—N—O 164–180°)	1.651	1.648	0.013	1.641	1.659	14
Fe—N	(4–6, ^‡): (Fe—N—O 144–180°)	1.671	1.666	0.028	1.650	1.681	51	92
	: (Fe—N—O > 155°)	1.669	1.666	0.023	1.650	1.680	50
Co—N	(4–6): (Co—N—O 124–180°)	1.697	1.667	0.084	1.640	1.805	22	8, 30, 92
	: (Co—N—O > 158°)	1.646	1.649	0.030	1.617	1.669	15
	(Co—N—O < 133°) excluding BUBBAB (1.705)	1.822	1.815	0.020	1.806	1.842	6
Ni—N	(3, 4): (Ni—N—O 161–180°)	1.628	1.629	0.024	1.612	1.649	11
Mo—N	(5–8): (Mo—N—O 166–180°)	1.787	1.779	0.041	1.760	1.804	44
Ru—N	(4–6): (Ru—N—O 143–180°)	1.751	1.752	0.038	1.732	1.766	12
	(Ru—N—O > 168°) excluding RUNCPP10 (1.839)	1.743	1.751	0.027	1.727	1.763	11
Rh—N	see NSDPRH10 (1.801)
W—N	(5–7): (W—N—O 168–180°)	1.792	1.800	0.034	1.770	1.822	7
Re—N	(4, 6): (Re—N—O 170–180°)	1.749	1.780	0.026	1.734	1.766	16
Os—N	(4–6): (Os—N—O 133–180°)	1.751	1.748	0.067	1.732	1.776	7	92
	Os—N—O > 174°: excluding NSOSPP10 (1.859)	1.733	1.743	0.051	1.708	1.771	6
Ir—N	(4, 5): (Ir—N—O 124–180°)	1.780	1.757	0.106	1.688	1.872	8	92
	(Ir—N—O > 163°) excluding CNOPIR (1.972), ICNPIR (1.900)	1.720	1.713	0.046	1.678	1.765	6

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.9.1.2 Nitrosyl (μ₂-NO)								78
N—O		1.210	1.208	0.025	1.195	1.218	19
Cr—N	see BRNOCR (1.892, 1.924)
Mn—N		1.855	1.858	0.007	1.850	1.860	18
Fe—N	see MENTFE (1.818)
Co—N		1.817	1.821	0.012	1.804	1.826	4
Ru—N	all BISKOD	1.918	1.919	0.005	1.913	1.922	4
Rh—N	see COBGIJ (1.952)
Os—N		2.042	2.040	0.029	2.014	2.073	6

Bond	Substructure (coordination number, oxidation state, comment)	Note^†
4.9.1.3 Nitrosyl (μ₃-NO)		78
N—O	(1.247)
Mn—N	see TCPMNN10 (1.933, 1.917, 1.939)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.9.2.1 Thionitrosyl (terminal NS)								80, 93
N—S		1.518	1.509	0.022	1.504	1.541	4
Cr—N	see CTNSCR10 (1.693)
Ru—N	see COGHEL (1.729)
Os—N	see CESNET (1.779), CIBKED (1.730)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.10.1.1 NH₂
(None)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.10.2.1 Primary amides (NHR)								94
N—C		1.434	1.429	0.035	1.404	1.470	4
Mo—N	see ADASMO (2.058), MPBMOE10 (1.955, 1.964)
Os—N	see BOSRUW (1.896)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.10.3.1 Secondary amides [NR₂, R = C(sp³)]								94
N—C		1.464	1.463	0.017	1.455	1.472	162
Ti—N	(4, 5), (IV): all	1.939	1.943	0.016	1.928	1.947	11
Zr—N	see TBIAZR (2.058, 2.062)
Mo—N	(4, 5), (III): (mainly Mo₂)	1.955	1.952	0.020	1.945	1.967	44
Tc—N	see CEWZIN10 (1.908, 1.916)
Ta—N	(5, 6), (V)	1.964	1.963	0.017	1.954	1.978	12
W—N	(4), (III, VI)	1.952	1.955	0.015	1.937	1.967	7
U—N	(4, 5), (IV)	2.206	2.212	0.033	2.172	2.235	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.10.3.2 Amides (μ₂-NR₂)
N—C	all C(sp³)	1.479	1.482	0.036	1.470	1.493	10
Ti—N	see BUNKEA (2.147, 2.191)
Cu—N	see CIDBAS (1.901, 1.907)
Mo—N	see PAIDMO (2.178, 2.250)
Au—N	see CASPIV (2.142, 2.139)
U—N	see URDEAM10 (2.456, 2.571)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.11.1.1 Amidinates [η¹-RNC(R)NR]
(None)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.11.1.2 Amidinates [chelating, η²-RNC(R)NR]								84
N—C		1.315	1.311	0.021	1.300	1.324	12
Mo—N	(7), (II)	2.171	2.177	0.021	2.148	2.188	10
Re—N	see BIYWUB (2.215, 2.217)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.11.1.3 Amidinates [bridging, μ₂-η¹, η^1′-RNC(R)NR]
N—C		1.340	1.336	0.022	1.323	1.352	22
Cr—N	all MBZACR	2.032	2.031	0.009	2.024	2.041	4
Mo—N	(5), (11)	2.149	2.151	0.016	2.134	2.161	12
Re—N	all PBARTC	2.077	2.076	0.015	2.063	2.092	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.12.1 Schiff bases (η¹-RN=CR₂)^§								95
N=C		1.287	1.286	0.021	1.275	1.300	768
N—C		1.471	1.473	0.022	1.461	1.485	765
Ti—N	see ESALTJ (2.136, 2.139)
V—N	(5, 6), (IV): all	2.047	2.041	0.024	2.036	2.054	7
Cr—N	(5, 6), (0, I, III): all	2.079	2.028	0.073	2.018	2.152	9
	(5, 6), (0)	2.153	2.152	0.032	2.123	2.182	4
	(6), (I, III)	2.019	2.019	0.006	2.014	2.025	5
Mn—N	(6, 7), (II, III): all	2.163	2.116	0.143	2.051	2.292	10	96, 97
Fe—N	(5–7), (0, II, III): all	2.038	1.992	0.103	1.942	2.109	78	30
	(5), (0): all	1.953	1.932	0.039	1.926	1.997	6
	(5, 6), (II): all	2.044	2.031	0.098	1.950	2.119	32	30
	: low spin	1.958	1.954	0.021	1.938	1.977	16
	: high spin	2.131	2.115	0.057	2.086	2.162	16
	(5, 6), (III): all	2.022	1.991	0.086	1.937	2.108	36	30
	: low spin	1.949	1.944	0.024	1.931	1.973	20
	: high spin	2.113	2.108	0.029	2.094	2.123	16
	(7), (II)	2.258	2.260	0.014	2.244	2.270	4
Co—N	(4–6), (I–III): all	1.943	1.917	0.084	1.891	1.946	142	30
	(4), (II)	1.907	1.876	0.065	1.871	1.921	25	86
	(5, 6), (II)	2.015	2.036	0.109	1.897	2.128	44	30
	: short (<1.95)	1.897	1.894	0.023	1.881	1.916	18
	: long (>1.99)	2.097	2.115	0.054	2.048	2.140	26
	(5, 6), (III): all	1.914	1.917	0.021	1.897	1.931	71
Ni—N	(4–6, ^‡), (0, II, IV): all	1.929	1.906	0.080	1.860	2.000	136
	(4), (0): all	1.924	1.924	0.006	1.922	1.930	7
	(4), (II)	1.888	1.871	0.048	1.855	1.917	77	86
	(5), (II): all	1.922	1.889	0.084	1.853	2.031	16	30
	: short (<1.925)	1.869	1.859	0.028	1.843	1.898	11
	: long (>2.025)	2.038	2.039	0.010	2.029	2.048	5
	6, (II): all	2.051	2.055	0.034	2.022	2.075	27
	6, (IV)	1.872	1.872	0.004	1.869	1.876	4
Cu—N	(3–6, ^‡), (I, II): all	1.969	1.964	0.053	1.936	1.990	227	86
	(3, 4), (I)	2.005	1.989	0.073	1.947	2.075	18
	(4), (II)	1.954	1.947	0.043	1.921	1.977	97
	(5), (II)	1.966	1.965	0.039	1.936	1.986	88
	(6), (II): all	2.010	2.005	0.049	1.966	2.049	14
Zn—N	(4–6, ^‡), (II): all	2.122	2.120	0.049	2.114	2.167	11
Zr—N	all SAZPZR	2.428	2.435	0.021	2.406	2.443	4
Mo—N	(5–7), (0–VI): all	2.189	2.181	0.065	2.131	2.237	31
	(6), (0)	2.244	2.254	0.042	2.203	2.274	6
	(7), (II)	2.216	2.221	0.028	2.204	2.233	10
	(-), (V, VI): excluding 2 > 2.30	2.124	2.130	0.013	2.113	2.133	12
Tc—N	(5, 6), (V)	2.034	2.023	0.029	2.002	2.066	7
Ru—N	see BAVSIA (2.190), COGXRU (2.138)
Rh—N	(4, 6), (I, III): all	2.053	2.039	0.046	2.013	2.103	8
	(6), (III)	2.023	2.026	0.019	2.005	2.039	5
Pd—N	(4, 5, ^‡), (II): all	2.037	2.032	0.040	2.017	2.046	26
Ag—N	(4–6), (I, II): all	2.403	2.429	0.112	2.311	2.447	9
Cd—N	see BEHMOQ (2.399, 2.457)
La—N	all EPAILA	2.714	2.721	0.025	2.688	2.734	4
Ce—N	(8), (IV)	2.615	2.614	0.025	2.608	2.638	8
W—N	see ALBCIW (2.219)
Re—N	(6), (V)	2.121	2.122	0.023	2.099	2.143	6
Os—N	[all μ-N(R)=C(R) clusters]	2.145	2.150	0.025	2.125	2.161	18
Ir—N	see SCLIRA10 (2.098)
Pt—N	see BISIPT (2.171, 2.176), BZHXDB (2.021, 1.995)
Au—N	see MEAZAU (1.976, 1.980)
Hg—N	see BOCWEV (2.158)
Th—N	(8), (IV): all	2.641	2.654	0.022	2.618	2.659	5
U—N	(7), (VI): excluding COKPIB (2.710)	2.572	2.568	0.012	2.565	2.586	6

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.13.1 Pyrroles^§
N—C¹		1.375	1.376	0.022	1.363	1.388	168
C¹—C²		1.429	1.434	0.039	1.399	1.453	168
C²—C^2′		1.368	1.371	0.025	1.350	1.384	83
Ti—N	see CPYRTI10 (2.067, 2.100)
Mn—N	(6), (-): all	2.126	2.141	0.041	2.095	2.148	5
Fe—N	(5, 6), (II, III): all	2.020	1.995	0.075	1.948	2.107	8
	(5, 6), (III)	1.969	1.985	0.031	1.936	1.995	5
Co—N	(5), (II)	2.044	2.063	0.033	2.009	2.065	6
Ni—N	(4), (II)	1.906	1.897	0.030	1.877	1.937	18
Cu—N	(4, 5), (II)	1.908	1.899	0.023	1.890	1.929	13
Zn—N	(4, 5), (II)	1.999	1.990	0.040	1.975	2.004	13
	(4), (II)	1.980	1.976	0.009	1.974	1.990	10
Zr—N	see CYPRZR10 (2.167, 2.170)
Mo—N	see BOXHUR (2.151)
Tc—N	see TPPTCC (2.161)
Rh—N	(4, ^‡), (I, II)	2.067	2.065	0.017	2.052	2.083	4
Pd—N	see BESFOU (2.010, 2.071)
Hf—N	see CESJOZ (2.164, 2.178)
Pt—N	see CAFFIY (2.045)
Hg—N	see FMTPHG (2.016), TAMPHG (2.325)
U—N	see CIMINU10 (2.490, 2.527, 2.533)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.13.2 Porphinates^§								98
N—C		1.380	1.379	0.011	1.373	1.385	564
Ti—N	(5), (IV)	2.112	2.115	0.016	2.098	2.124	8
V—N	(5, 6), (II, IV)	2.085	2.098	0.027	2.051	2.104	6
Cr—N	(4, 5), (II, V)	2.037	2.036	0.005	2.033	2.042	6
Mn—N	(4–6), (II–IV): all	2.024	2.013	0.046	1.998	2.030	34
	(4–6), (II)	2.057	2.029	0.053	2.009	2.124	14
	(5, 6), (III, IV)	2.001	2.002	0.020	1.992	2.016	20
Fe—N	(4–6), (II, III): all	2.031	2.038	0.036	1.995	2.062	88	30, 98, 99
	(4–6), (II)	2.009	2.000	0.035	1.987	2.006	22
	(4–6), (III)	2.034	2.050	0.034	1.999	2.067	66
	(4–6), (II, III): short (<2.014)	1.995	1.995	0.009	1.991	2.003	41
	(4–6), (II, III): long (>2.022)	2.063	2.062	0.017	2.051	2.074	47
Co—N	(4–6), (II, III): all	1.969	1.983	0.022	1.947	1.988	19
Ni—N	(4), (II)	1.943	1.949	0.014	1.931	1.954	16
Cu—N	(4), (II)	1.991	1.992	0.009	1.985	1.996	6
Zn—N	(4, 5), (II)	2.068	2.063	0.024	2.058	2.074	18
Nb—N	(6, 7), (V)	2.234	2.239	0.037	2.209	2.247	16
Mo—N	(5, 6), (II, IV): excluding OTPHMO	2.086	2.090	0.017	2.075	2.097	28	44
Ru—N	(5, 6), (II, III)	2.047	2.047	0.007	2.043	2.055	24
Rh—N	(5, 6), (III)	2.034	2.031	0.010	2.026	2.042	6
Cd—N	all PHPNCD	2.145	2.150	0.029	2.115	2.169	4
Pt—N	see CEZKEX (2.005)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.13.3 Phthalocyanines^§
N—C		1.380	1.381	0.011	1.379	1.389	70
Ti—N	(5), (IV): all BITSAY	2.066	2.064	0.013	2.055	2.080	4
V—N	(5), (IV): all VPHTHC	2.026	2.029	0.013	2.012	2.037	4
Mn—N	see MNPHCY03 (1.938, 1.939)
Fe—N	(4, 6), (II)	1.934	1.931	0.009	1.927	1.941	6
Co—N	(4, 6), (II)	1.921	1.915	0.017	1.910	1.938	4
Ni—N	see NIPHTI (1.887)
Zn—N	see PTHCZN (1.978, 1.980)
Nb—N	(6), (IV): all BEJTIT	2.144	2.144	0.015	2.129	2.159	4
Nd—N	all CIZGIB02	2.471	2.471	0.009	2.463	2.479	4
Os—N	(6), (II): all PCPCOS	2.016	2.015	0.041	1.980	2.055	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.14.1.1 Pyrazolates (η¹-C₃R₃N₂)^§
N¹—N²	(1.361, 1.369, 1.367)
N¹—C⁵	(1.347, 1.350, 1.345)
N²—C³	(1.340, 1.332, 1.327)
C³—C⁴	(1.376, 1.386, 1.383)
C⁴—C⁵	(1.384, 1.368, 1.373)
Mo—N	see CAFLEA (2.157, 2.166)
Ir—N	see BIXBUF10 (2.080)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.14.1.2 Pyrazolates (μ₂-η¹, η^1′-C₃R₃N₂)^§
N—N		1.367	1.368	0.014	1.360	1.375	34
N—C		1.345	1.345	0.020	1.338	1.350	68
C—C		1.378	1.377	0.017	1.370	1.385	68
Ti—N	see PZCPTI (2.205, 2.183)
Fe—N	all DMPZFE	2.005	2.007	0.004	2.001	2.009	4
Co—N	all DMPZCO	1.988	1.988	0.007	1.982	1.995	4
Ni—N	(3, 4), (0–II)	1.957	1.971	0.044	1.917	1.997	16
Cu—N	(3, 5), (I, II)	1.929	1.934	0.035	1.892	1.958	8
Rh—N	(4–6), (I, III): all	2.080	2.084	0.017	2.065	2.094	24
Pd—N	all PZALPD10	2.073	2.071	0.006	2.069	2.079	4
Ir—N	(4, 5), (I, II)	2.070	2.078	0.022	2.053	2.091	7

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.14.2.1 Imidazolates (η¹-C₃R₃N₂)^§
N¹—C²		1.344	1.345	0.023	1.329	1.360	21
N¹—C⁵		1.376	1.369	0.026	1.355	1.398	21
C²—N³		1.336	1.338	0.017	1.322	1.346	21
N³—C⁴		1.356	1.355	0.024	1.340	1.372	21
C⁴—C⁵		1.380	1.382	0.021	1.373	1.393	21
Co—N	see ACNTCC (2.005), CTENCO20 (1.956)
Cu—N	(4, 5), (II): all	1.994	1.992	0.024	1.980	2.009	6
Pd—N	see ADBPPD (2.015)
Ag—N	see IMDZAG (2.074, 2.098)
Ir—N	see CEXZIO (2.321, 2.116), CEXZOU (2.081), CEYBEN (2.081)	2.035	2.030	0.035	2.005	2.070	4
Pt—N	(4), (II)
Hg—N	see ADMEHH (2.070), CIRMAR (2.081)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.14.2.2 Imidazolates (μ₂-η¹, η^1′-C₃N₂R₃)^§
N¹—N²		1.332	1.332	0.012	1.325	1.341	49
N¹—C⁵		1.372	1.373	0.016	1.363	1.381	49
C⁴—C⁵		1.358	1.354	0.015	1.348	1.368	25
Mn—N	all IMIDZA	2.154	2.114	0.078	2.099	2.250	6	30
Fe—N	(4, 6), (II)	2.065	2.043	0.070	2.012	2.137	8
Cu—N	(4–6), (II): excluding BIMTCU (2.323)	1.966	1.967	0.022	1.957	1.979	19
Zn—N	see IMZZNN (1.986, 1.993)
Rh—N	(4, 5), (-)	2.104	2.104	0.034	2.071	2.138	8
Ir—N	see CEYBEN (2.087, 2.094)
Hg—N	(2, 3), (II)	2.086	2.084	0.008	2.079	2.094	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.14.3 N-Alkylpyrazoles^§
N¹—N²		1.360	1.360	0.015	1.350	1.368	53
N¹—C⁵		1.331	1.333	0.015	1.324	1.340	53
N²—C³		1.349	1.350	0.012	1.342	1.358	53
C³—C⁴		1.356	1.358	0.020	1.344	1.371	53
C⁴—C⁵		1.387	1.387	0.015	1.377	1.396	53
N²—C(R)		1.452	1.452	0.023	1.439	1.469	53
Cr—N	all CEYBIR	2.101	2.097	0.023	2.082	2.128	6
Co—N	see DPPTCC (2.021, 2.036)
Ni—N	(5, 6), (II)	2.057	2.047	0.031	2.034	2.089	4
Cu—N	(2, 4, 5, ^‡), (I, II): all	1.973	1.979	0.072	1.927	1.994	19
	(2), (I)	1.876	1.878	0.009	1.867	1.884	4
	(4), (I)	1.991	1.990	0.039	1.963	2.030	8
	(4, 5), (II): excluding BENDED (2.173)	1.985	1.985	0.007	1.979	1.992	5
Mo—N	see CAFLAW (2.123)
Rh—N	see COSTIN (2.102, 2.111)
Pd—N	(4), (II)	2.026	2.031	0.018	2.007	2.040	4
Ag—N	see PMPZAG10 (2.243)
Pt—N	(4, 6), (II, IV): all	2.189	2.210	0.064	2.121	2.236	4
Au—N	see BOFCEE (2.130, 2.141)
Th—N	all FAPZTH10	2.637	2.633	0.017	2.624	2.655	4
U—N	all UHXAPY10	2.574	2.582	0.024	2.549	2.593	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.14.4 N-Alkylimidazoles^§
N¹—C²		1.346	1.344	0.014	1.337	1.353	103
C²—N³		1.320	1.320	0.017	1.310	1.328	104
N³—C⁴		1.382	1.380	0.016	1.370	1.393	104
N¹—C⁵		1.369	1.369	0.015	1.361	1.380	104
C⁴—C⁵		1.359	1.362	0.023	1.342	1.375	104
N¹—C(R)		1.468	1.468	0.020	1.458	1.480	104
Mn—N	see MNTPPI10 (2.191)
Fe—N	(6), (II): excluding BERTAT (2.021)	2.199	2.191	0.018	2.183	2.218	5
Co—N	(4–6), (II, III): all	2.058	2.036	0.065	2.015	2.096	21	8
	(4), (II)	2.019	2.016	0.008	2.013	2.026	6
	(5, 6), (II)	2.100	2.096	0.067	2.031	2.161	10
	(6), (III)	2.021	2.042	0.053	1.970	2.062	5
Ni—N	see CESKIU (2.102, 2.110)
Cu—N	(4–6), (I, II): all	2.022	2.004	0.051	1.995	2.046	33
	(4), (II)	1.974	1.970	0.019	1.959	1.995	7
	(5), (II)	2.040	2.007	0.061	1.996	2.092	16
	(6), (II)	2.023	2.022	0.021	2.006	2.041	9
Zn—N	see CEPGUZ (2.083), MADCZB10 (2.040)
Mo—N	see COFZEC (2.141, 2.273)
Ru—N	see BAKDUM (2.094)
Rh—N	see RACCAF (2.316)
Pd—N	see COHCUX (1.988), ENGUPD (2.013), TCMIPD10 (2.011)
Ag—N	(2, 3), (I)	2.141	2.139	0.016	2.126	2.155	8
Cd—N	see BEGNAC (2.358)
Pt—N	(4), (II): all	2.017	2.015	0.014	2.008	2.027	20
Hg—N	see BEJGIG (2.132), CAGSIM (2.125), MEGUHG (2.087)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.14.5 Pyrazole^§
N¹—N²		1.352	1.353	0.015	1.345	1.356	43
N²—C³		1.329	1.329	0.009	1.325	1.336	42
N¹—C⁵		1.339	1.338	0.010	1.333	1.345	43
C⁴—C⁵		1.357	1.357	0.019	1.350	1.367	43
C³—C⁴		1.388	1.387	0.017	1.376	1.396	43
Mn—N	(6), (I, II): all	2.209	2.240	0.071	2.168	2.249	6
	(6), (II)	2.237	2.243	0.021	2.219	2.252	5
Fe—N	see MEPZFE (2.068)
Co—N	see FMPZCO (2.032, 2.040, 2.042)
Ni—N	(6), (II): excluding PYRZNI (1.905, 1.908)	2.102	2.098	0.016	2.089	2.118	4
Cu—N	(5, 6), (II)	1.988	1.995	0.030	1.964	2.011	12
Zn—N	see CIRVOO (2.016, 2.017)
Mo—N	(6, 7), (0, II, III): all	2.193	2.174	0.059	2.142	2.251	6
Ru—N	see CIZBES (2.211)
Rh—N	(4, 6), (I, III)	2.102	2.100	0.016	2.088	2.118	4
Pd—N	see BABTUT (2.101)
Pt—N	see CEZMUP (2.027)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.14.6 Pyrazolylborates^§
N¹—N²		1.366	1.366	0.012	1.360	1.372	210
N²—N³		1.339	1.339	0.014	1.329	1.347	211
N¹—C⁵		1.347	1.347	0.011	1.340	1.354	209
C⁴—C⁵		1.366	1.368	0.016	1.360	1.375	211
C³—C⁴		1.383	1.382	0.015	1.373	1.391	210
N¹—B		1.546	1.543	0.019	1.535	1.555	211
Cr—N	(4), (II)	2.061	2.060	0.006	2.057	2.067	4
Fe—N	(6, 7), (II, III): all	2.129	2.147	0.055	2.102	2.169	22
Co—N	(4, 6), (II, III): all	1.948	1.951	0.048	1.916	1.979	6	30
Ni—N	all PYZBNI [excluding PPZBNI (1.891)]	2.092	2.090	0.007	2.087	2.099	6
Cu—N	(2–6), (I, II): all	2.035	2.002	0.134	1.949	2.052	29	86
	(2–5), (I)	2.001	1.987	0.075	1.946	2.041	23
	(3), (1)	1.936	1.941	0.028	1.913	1.958	5
Zr—N	see CEFHEA (2.387, 2.438, 2.430)
Mo—N	(5–7), (0–VI): all	2.218	2.219	0.042	2.188	2.245	90
Tc—N	see CHBPTC (2.088, 2.089, 2.259)
Ru—N	see PZBZRU10 (2.101, 2.112)
Rh—N	(4–6), (I, III): all	2.098	2.083	0.043	2.071	2.123	12
Ag—N	see PRZBAG (2.194, 2.412)
Yb—N	all BORVIN	2.469	2.453	0.074	2.405	2.530	8
Ta—N	see CEXHUI (2.227, 2.273, 2.294)
W—N	(6), (-)	2.215	2.213	0.028	2.200	2.218	9
Pt—N	(4, 5), (II)	2.098	2.121	0.050	2.054	2.129	9
Au—N	see CEPMAL (2.119, 2.127)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.14.7 Pyrazolylgallates^§
N¹—N²		1.370	1.368	0.009	1.362	1.377	40
N²—C³		1.336	1.339	0.014	1.334	1.344	40
N¹—C⁵		1.344	1.344	0.011	1.339	1.352	40
C⁴—C⁵		1.363	1.364	0.017	1.355	1.372	40
C³—C⁴		1.380	1.381	0.012	1.373	1.386	40
N¹—Ga		1.966	1.975	0.029	1.942	1.989	40
Mn—N	see BATZIF (2.077), BEWVEE (2.076, 2.080)
Fe—N	see MEPGFE (2.107)
Ni—N	(4–6), (0–II): all	1.986	1.981	0.075	1.920	2.068	11
	(4), (0–II)	1.932	1.922	0.038	1.898	1.976	6
Cu—N	(4), (I, II)	1.982	1.979	0.026	1.960	2.006	5
Mo—N	(5–7), (0–II): all	2.252	2.264	0.048	2.221	2.288	13
	(7), (-)	2.267	2.270	0.033	2.237	2.289	11
Rh—N	(4, 6), (I, II)	2.168	2.173	0.038	2.168	2.188	7

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.14.8 Imidazole^§
N³—C²		1.324	1.324	0.012	1.316	1.330	194
N³—C⁴		1.381	1.380	0.015	1.372	1.391	197
C²—N¹		1.340	1.339	0.014	1.332	1.347	196
N¹—C⁵		1.369	1.366	0.018	1.358	1.379	196
C⁴—C⁵		1.361	1.356	0.021	1.347	1.373	197
Cr—N	see BOPPIF10 (2.062, 2.050), LDHPCR10 (2.057)
Mn—N	(5, 6), (I, II): all	2.237	2.248	0.057	2.196	2.276	10
	(5, 6), (II)	2.251	2.266	0.042	2.205	2.279	9
Fe—N	(4, 6), (-): all	2.157	2.152	0.091	2.107	2.235	7
Co—N	(4–6), (II, III): all	2.010	2.013	0.077	1.930	2.089	22	8
	(4), (II)	2.022	2.019	0.011	2.013	2.034	4
	(5, 6), (II)	2.103	2.097	0.028	2.088	2.112	7
	(6), (III)	1.946	1.930	0.036	1.916	1.958	11
Ni—N	(4, 6), (II): all	2.103	2.099	0.024	2.082	2.128	30
Cu—N	(3–6), (I, II): excluding IMZCUN (2.593)	1.988	1.981	0.050	1.961	2.008	82
	(4), (II)	1.982	1.981	0.024	1.963	2.001	19
	(5), (II): all	1.984	1.975	0.038	1.961	1.997	35	86
	(5), (II): excluding 2 > 2.07	1.976	1.974	0.020	1.961	1.994	33
	(6), (II): excluding 3 > 2.13	1.996	2.009	0.038	1.954	2.029	23
Zn—N	(4–6), (II)	2.043	2.056	0.044	1.997	2.076	21
	(4), (II)	2.023	2.010	0.033	1.995	2.056	11
	(6), (II)	2.084	2.076	0.027	2.066	2.098	8
Mo—N	see MOSHIS10 (2.238, 2.245)
Ru—N	see BAKDOG (2.087)
Pd—N	see BOLRID (2.005), HISTPD (2.029)
Ag—N	see ADAGPC (2.154), AGIMHN01 (2.118, 2.132)
Cd—N	(6, 8), (II)	2.302	2.290	0.054	2.255	2.349	11
Os—N	see CASVIB (2.153)
Ir—N	see CEYBEN (2.081)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.15.1 Pyridine^§
N—C²		1.341	1.339	0.018	1.331	1.348	612
C²—C³		1.382	1.380	0.020	1.371	1.393	613
C³—C⁴		1.372	1.372	0.021	1.360	1.384	610
Ti—N	see ESALTJ (2.279)
V—N	see TPYCLV (2.188)
Cr—N	(6), (-)	2.178	2.158	0.076	2.147	2.171	11	100
	(6), (-)	2.146	2.158	0.030	2.122	2.168	9	85
Mn—N	see BANVUH10 (2.018), COTGEX (2.377), FACMNB (2.086, 2.109)
Fe—N	(5, 6), (0, II, III): all	2.224	2.242	0.102	2.148	2.270	14	87, 96
Co—N	(4–6), (II, III): all	2.082	2.066	0.084	2.004	2.172	50	8
	(6), (III): excluding CORHOG (2.214)	2.034	2.040	0.044	1.992	2.071	29
	(6), (II): excluding BACREC10 (1.953, 1.963)	2.185	2.183	0.037	2.170	2.214	15
Ni—N	(4, 6), (-): all	2.111	2.116	0.059	2.085	2.150	33
	(6), (-)	2.122	2.117	0.042	2.096	2.152	31
Cu—N	(-), (-) : all	2.070	2.046	0.072	2.033	2.061	32	86
	(4), (-)	2.024	2.023	0.019	2.007	2.043	4
	(5), (-)	2.113	2.060	0.105	2.024	2.183	11
	(6), (-)	2.054	2.046	0.032	2.039	2.055	16
Zn—N	(4–6), (-)	2.095	2.081	0.063	2.051	2.149	16
	(4), (-)	2.064	2.064	0.057	2.027	2.115	6
	(5), (-)	2.116	2.121	0.069	2.046	2.178	6
	(6), (-)	2.111	2.099	0.058	2.063	2.173	4
Mo—N	(5–7), (-): all	2.300	2.279	0.078	2.252	2.336	25	15, 100
	: excluding HPHOMO10 (2.446)	2.282	2.278	0.046	2.249	2.329	23	85
Ru—N	(6), (I–III): all	2.124	2.108	0.049	2.095	2.138	28	100
		2.114	2.107	0.031	2.094	2.121	26	85
Rh—N	(6), (II–III): all	2.119	2.066	0.090	2.056	2.222	13	30, 100
		2.063	2.062	0.016	2.050	2.075	9	85
Pd—N	(4), (-)	2.089	2.085	0.061	2.033	2.149	4
Ag—N	(-), (-)	2.299	2.322	0.056	2.228	2.331	7
Cd—N	(6, 7), (-)	2.381	2.368	0.042	2.355	2.413	5
Ta—N	see PCTATL10 (2.423)
W—N	(5, 6): all	2.284	2.283	0.098	2.201	2.323	11
	: excluding CAKTUD (2.528)	2.260	2.263	0.059	2.196	2.322	10
Re—N	(5, 6), (IV–VII): all	2.235	2.176	0.114	2.142	2.339	13	87
Os—N	(6), (-): all	2.165	2.169	0.053	2.106	2.217	6
Ir—N	see PCHIRH10 (2.140), PHPCIR10 (2.176)
Pt—N	(4, 6), (-): all	2.085	2.061	0.078	2.036	2.125	11
	(4), (-)	2.050	2.045	0.048	2.014	2.091	8
Hg—N	excluding ETACHG (2.656)	2.164	2.146	0.054	2.127	2.198	6	26

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.15.2 2,2′-Bipyridyl (chelating, η²-bpy)^§
N—C		1.352	1.351	0.017	1.343	1.359	329
C²—C^2′		1.471	1.474	0.021	1.462	1.481	166
V—N	(5, 6), (-): all	2.186	2.151	0.075	2.126	2.280	12	30
	: short (<2.2)	2.137	2.133	0.028	2.114	2.153	8
Cr—N	(6), (III): all	2.085	2.076	0.037	2.059	2.088	20	30
Mn—N	see BPYMNA (2.291, 2.311), TNBPMN (2.087, 1.996)
Fe—N	(5, 6), (0, II, III): all	2.008	1.964	0.089	1.958	2.123	23	30
	(5, 6), (II, III): low spin	1.961	1.962	0.012	1.954	1.967	16
	(6), (III): high spin	2.151	2.153	0.024	2.123	2.172	6
Co—N	(6), (II, III): all	2.098	2.129	0.093	2.072	2.147	10	8, 30
	(6), (II)	2.141	2.133	0.023	2.126	2.152	8
Ni—N	(4, 5, 6), (-): all	1.956	1.948	0.044	1.934	1.960	12	9
	(4)	1.944	1.939	0.033	1.921	1.959	9
Cu—N	(4, 5, 6), (-): all	2.031	2.007	0.057	1.991	2.071	108	12, 86
	(4), (II)	2.002	1.997	0.025	1.986	2.018	12
	(5), (-)	2.038	2.010	0.062	1.992	2.081	70	86
	(6), (-)	2.024	2.003	0.053	1.990	2.053	22	86
Zn—N	(-), (-): all	2.088	2.090	0.034	2.056	2.117	4
Zr—N	see TCBPZR (2.412)
Nb—N	see TCBPNB (2.319)
Mo—N	(5, 6, 7), (-): all	2.260	2.251	0.074	2.210	2.314	32	15
Ru—N	(6), (-): all	2.064	2.063	0.028	2.044	2.087	34
Rh—N	see BIHJORH10 (2.020, 2.029)
Pd—N	(3, 4, 6), (0, II, IV): all	2.088	2.086	0.087	2.014	2.169	8
Ag—N	see BPYAGN (2.179, 2.153)
Cd—N	(6), (-): all	2.369	2.367	0.033	2.339	2.396	14
Re—N	see DPCLRE10 (2.245)
Os—N	see CIXLIE (2.071, 2.112)
Ir—N	(6), (-)	2.071	2.049	0.042	2.039	2.115	20
Pt—N	see BIBFUN (2.107, 2.103), BPYCPT (2.001)
Hg—N	(5, 6, 7), (-): all	2.307	2.293	0.057	2.276	2.358	8
U—N	(9), (-): all	2.627	2.623	0.018	2.612	2.646	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.15.3 Phenanthroline (chelating, η²-o-phen)^§
N—C		1.361	1.360	0.014	1.353	1.367	157
C²—C^2′		1.428	1.429	0.017	1.419	1.439	84
Ti—N	see PNOLTI (2.147, 2.223)
Cr—N	see BUWYIB (2.055, 2.057)
Mn—N	(6), (I, II): all	2.106	2.069	0.070	2.055	2.190	6
	(6), (I)	2.062	2.052	0.013	2.055	2.075	4
Fe—N	(6), (II): all	2.059	1.982	0.122	1.968	2.182	25
	: tris-phen only	1.969	1.970	0.015	1.958	1.979	15
Co—N	(6), (I–III): all	2.027	1.998	0.096	1.943	2.133	16	30
	(6), (I, II)	2.141	2.137	0.020	2.124	2.156	6
	(6), (III)	1.958	1.947	0.033	1.938	1.992	10
Ni—N	(4–6), (II): all	2.053	2.063	0.047	2.009	2.092	16	9
	(4), (II)	1.989	1.985	0.011	1.982	2.001	4
	(5), (II)	2.034	2.033	0.011	2.024	2.045	4
	(6), (II)	2.093	2.092	0.015	2.080	2.104	8
Cu—N	(4–6), (I, II): all	2.059	2.023	0.069	2.009	2.087	51	12, 86
	(4), (I)	2.083	2.078	0.040	2.056	2.122	14
	(5), (II): excluding 3 > 2.21	2.021	2.015	0.027	2.009	2.021	18
	(6), (II): short (<2.05)	2.008	2.005	0.016	1.998	2.012	10
	: long (>2.09)	2.129	2.124	0.025	2.111	2.149	5
Zn—N	(4), (II)	2.063	2.063	0.007	2.057	2.069	4
Nb—N	see OPENBO10 (2.280, 2.332)
Mo—N	(5, 6), (0, IV, VI):	2.276	2.273	0.076	2.205	2.351	4
Ru—N	see MPTBRH (2.083, 2.092)
Rh—N	(6), (III): all CELLAG	1.934	1.933	0.009	1.925	1.934	4
Cd—N	(6, ^‡), (II)	2.369	2.368	0.018	2.354	2.384	5
Ir—N	see CAYGAK (2.085, 2.122)
Pt—N	see BOVLED (2.165, 2.175), CNPLPT (2.053, 2.762; 2.063, 2.007)
Hg—N	(4, 6, 8), (II): all	2.486	2.408	0.147	2.391	2.669	11	30

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.16.1.1 Pyrazines (η¹-C₄R₄N₂)^§
N¹—C²		1.340	1.336	0.016	1.330	1.344	36
C²—C³		1.390	1.387	0.022	1.376	1.403	37
C³—N⁴		1.334	1.334	0.018	1.325	1.342	38
Cr—N	see ACPCRB (2.315)
Fe—N	see PYZTCI (2.031)
Co—N	(6), (II): all	2.145	2.125	0.054	2.104	2.190	6
Cu—N	(5, 6), (II): excluding PYZCUA01 (2.167)	2.011	2.004	0.041	1.975	2.053	4
Zn—N	see AZNPYD (2.145)
Ru—N	see CABYIN (2.129, 2.152), PYZRUA (2.006)
Rh—N	see PRNRHC (2.363)
Ir—N	see CLPZIR (2.018)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.16.1.2 Pyrazines (μ₂-C₄R₄N₂)^§
N—C		1.337	1.333	0.022	1.326	1.345	18
C—C		1.383	1.380	0.015	1.369	1.398	9
Cu—N	(4, 5), (II)	2.024	2.016	0.021	2.009	2.046	4
Rh—N	see BUZZAX (2.100)
Pd—N	see BENDAZ (2.051)
Yb—N	see CPPYYB01 (2.614)
Hg—N	see PAZHGN (2.263)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.16.2.1 Pyridazines (η¹-C₄R₄N₂)^§
N¹—N²		1.334	1.334	0.006	1.328	1.340	4
N¹—C⁶		1.325	1.327	0.007	1.318	1.330	4
N²—C³		1.335	1.334	0.005	1.329	1.337	4
C³—C⁴		1.374	1.377	0.026	1.349	1.397	4
C⁴—C⁵		1.347	1.351	0.012	1.334	1.356	4
C⁵—C⁶		1.388	1.387	0.017	1.373	1.405	4
Fe—N	see TAZCFE (2.013)
Cu—N	see BEJNIN (2.052, 2.071), PYAZCU10 (2.122)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.16.2.2 Pyridazines (μ₂-C₄R₄N₂)^§
N¹—N²		1.352	1.357	0.028	1.333	1.373	14
N¹—C⁶		1.319	1.316	0.020	1.303	1.335	28
C³—C⁴		1.417	1.415	0.027	1.392	1.442	28
C⁴—C⁵		1.373	1.380	0.038	1.337	1.406	14
Fe—N	see DAZHCF (1.955, 1.956)
Ni—N	see HPCXNI (2.075, 2.060)
Cu—N	(4–6, ^‡), (II): all	2.015	2.013	0.029	1.988	2.039	22
Ru—N	see DAZRUC10 (2.132, 2.136)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.16.3.1 Pyrimidines (η¹-C₄R₄N₂)^§
N¹—C²		1.360	1.361	0.026	1.346	1.377	95
N¹—C⁶		1.361	1.357	0.022	1.349	1.374	95
N³—C²		1.345	1.342	0.033	1.321	1.374	95
N³—C⁴		1.359	1.356	0.024	1.341	1.377	95
C⁴—C⁵		1.372	1.375	0.030	1.351	1.395	95
C⁵—C⁶		1.401	1.397	0.029	1.378	1.422	95
Co—N	(4, II) or (6, III): excluding CICYAO (2.158)	1.981	1.981	0.006	1.976	1.987	4
Ni—N	see URCLNI (2.144)
Cu—N	(3–6), (I, II): excluding CLPRCV	2.006	1.992	0.047	1.981	2.020	19
	(4–6), (II)	1.999	1.992	0.027	1.981	2.016	16
Zn—N	(4, 6), (II): all	2.065	2.065	0.013	2.056	2.074	6
Mo—N	(5, 6), (II, V): all	2.203	2.183	0.058	2.158	2.243	10
	(5), (II)	2.178	2.173	0.026	2.157	2.198	8
Pd—N	see BUCBUW (2.086), DCMCPD (2.031)
Ag—N	(2–5), (I): all	2.188	2.188	0.026	2.167	2.209	5
Cd—N	(4–6, 8), (II): all	2.295	2.295	0.065	2.239	2.324	7
	(4–6), (II)	2.275	2.289	0.042	2.232	2.304	6
W—N	(5, 8), (II, IV): all	2.161	2.163	0.010	2.156	2.169	8
Pt—N	(4, 5), (II): all	2.033	2.033	0.015	2.024	2.044	26
Hg—N	(2, 5), (II): all	2.117	2.100	0.033	2.092	2.151	5

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.16.3.2 Pyrimidines (μ₂-C₄R₄N₂)^§
N¹—C²		1.349	1.351	0.019	1.328	1.367	6
N¹—C⁶		1.330	1.322	0.024	1.310	1.353	6
C⁴—C⁵		1.378	1.375	0.044	1.354	1.406	6
Ti—N	see PMDTTI10 (2.174, 2.239)
Cu—N	see COPFOC (2.007, 2.011)
Ag—N	see SULPMS (2.205, 2.460)

Bond	Substructure (coordination number, oxidation state, comment)	Note^†
4.17.1 Hydrazido(1−)(η¹-NRNR₂)		80
N—N	(1.318, 1.388)
Re—N	see CEXKAR (1.949)
Ir—N	see NPHZIR (1.912)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.17.2 Hydrazido(2–)(η¹-NNR₂, R = C, H)								80
N—N		1.300	1.293	0.032	1.282	1.324	16
Fe—N	see CESTOJ (1.811)
Mo—N	(5, 6), (II, IV, VI)	1.768	1.764	0.024	1.748	1.794	9	77
W—N	(6, 7), (IV, V)	1.751	1.752	0.014	1.738	1.763	5
Re—N	see BILMUE (1.937)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.17.3.1 Diazenes (η¹-RNNR)^§
N—N	(1.235, 1.240, 1.131)
Pd—N	see DCAZPD (2.023, 2.023)
Au—N	see AZTLAW (2.151)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.17.3.2 Diazenes (η²-RNNR)^§
N—N	(1.340)
Ti—N	see AZBCTI10 (1.965, 1.971)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.17.4.1 Hydrazines (η¹-NR₂NR₂)
N—N		1.424	1.421	0.020	1.411	1.433	81
Mn—N	see PHYZMN (2.345)
Fe—N	see BEPZIF (2.273, 2.276)
Co—N	(5, 6), (II, III): all	2.105	2.173	0.115	1.980	2.208	7	30
	(5, 6), (II)	2.196	2.194	0.024	2.175	2.220	4
Ni—N	(4, 6), (II): all	2.100	2.119	0.064	2.093	2.133	21
	(6), (II)	2.118	2.120	0.027	2.101	2.133	19
Cu—N	(4–6), (I, II): all	2.019	2.011	0.033	2.004	2.033	15
Zn—N	(6), (II)	2.158	2.167	0.022	2.130	2.175	7
Ru—N	see DMHERU01 (2.166, 2.279, 2.203)
Rh—N	(6), (III)	2.118	2.115	0.023	2.098	2.136	10
Cd—N	(6), (II)	2.451	2.469	0.070	2.367	2.502	6
Sm—N	see ISNHSM (2.628, 2.651, 2.719)
Dy—N	see CECLIF10 (2.570)
Er—N	all CECLEB10	2.540	2.537	0.010	2.533	2.550	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.17.4.2 Hydrazines (μ₂-NR₂NR₂)
N—N	(1.423)
Fe—N	see HZBTFE (2.245)

Bond	Substructure (coordination number, oxidation state, comment)	Note^†
4.18.1.1 Triazenido (terminal, η¹-RNNNR)^§		84, 101
(M)N—N	(1.336, 1.333, 1.339)
N—N	(1.286, 1.282, 1.274)
Pd—N	see CTAZPD10 (2.033)
Pt—N	see PAZPPT10 (2.084, 2.089)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.18.1.2 Triazenido (chelating, η²-RNNNR)^§								101
N—N		1.308	1.313	0.024	1.298	1.322	6
Mo—N	see TLTZMO (2.232, 2.270)
Ru—N	see TAZRUP10 (2.149, 2.179)
Hg—N	see MNAZHG (2.313, 2.434)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.18.1.3 Triazenido (μ-η¹, η^1′-RNNNR)								101
N—N		1.308	1.303	0.020	1.295	1.318	46
Cu—N	all CUDPTZ10	2.019	2.008	0.044	1.980	2.061	8
Zn—N	all BISPAU	2.002	2.003	0.012	1.992	2.013	6
Mo—N	(5), (III): (asymmetric)	2.212	2.210	0.056	2.159	2.261	6
Rh—N	(5), (-)	2.117	2.117	0.022	2.095	2.138	8
Pd—N	(5), (II)	2.078	2.079	0.042	2.034	2.123	16
W—N	see MOPAZW (2.107, 2.096)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.19.1.1 Hydrazones and related ligands (η¹-NR₂N = CR₂)
N—N		1.382	1.380	0.021	1.367	1.397	137
N=C		1.294	1.293	0.017	1.281	1.308	137
Cr—N	(7), (III): see COHTOI (2.196, 2.259), DAPSCR10 (2.023, 2.397)
Mn—N	(5–7), (II)	2.293	2.289	0.030	2.274	2.316	12
Fe—N	(6, 7), (II, III): all	2.100	2.124	0.126	1.957	2.202	14	96
Co—N	(5–7), (I, II)	2.171	2.169	0.049	2.148	2.198	30
Ni—N	(5–7,^‡), (II): all	2.102	2.095	0.060	2.071	2.126	38
	(6), (II)	2.092	2.093	0.049	2.065	2.111	32
Cu—N	(4–6), (II): excluding 2 > 2.40	1.986	1.982	0.047	1.938	2.036	20
Zn—N	(4, 6, 7), (II): all	2.232	2.234	0.069	2.187	2.293	6
	(6, 7), (II)	2.255	2.247	0.043	2.216	2.299	5
Mo—N	see CLOSMO (2.194)
Pd—N	(4), (II)	2.043	2.030	0.031	2.020	2.068	6
Yb—N	see PCPHYB (2.534)
Pt—N	see BHZEPT (2.221), COPGAP (2.249), HAPZPT10 (2.166)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.20.1 vic-Dioximes [chelating, η²-N(O)CRCRN(O)]^§
N—C		1.299	1.299	0.014	1.291	1.308	548
N—O		1.356	1.352	0.026	1.339	1.369	550
C—C		1.467	1.466	0.019	1.456	1.482	268
Fe—N	(6), (II)	1.901	1.901	0.018	1.886	1.918	4
Co—N	(4, 6), (II, III): all	1.893	1.889	0.030	1.882	1.897	363	102
	(6), (II): excluding FLDXCO10 (2.12–2.15)	1.903	1.897	0.026	1.887	1.928	12
	(6), (III)	1.890	1.888	0.014	1.881	1.896	332
Ni—N	(4, 6), (II): all	1.939	1.872	0.103	1.864	2.067	45	9, 30
	(4), (II)	1.869	1.868	0.013	1.860	1.872	30
	(6), (II)	2.079	2.082	0.035	2.054	2.105	15
Cu—N	(4–6), (I, II): all	2.012	1.992	0.072	1.961	2.034	38	30
	(4, 5), (I)	2.135	2.137	0.022	2.110	2.156	10
	(4–6), (II)	1.974	1.980	0.027	1.951	1.998	28
Rh—N	(6), (III)	2.009	1.998	0.034	1.988	2.023	34
Pd—N	(4, 5, ^‡), (II)	1.991	1.983	0.023	1.973	2.002	28
Pt—N	(4, 6, ^‡), (II, IV)	1.994	1.991	0.019	1.980	2.010	38

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.21.1 N-Nitrite (η¹-NO₂) (see also 5.12.1)								103, 104
N—O		1.221	1.227	0.027	1.212	1.236	172	91
Cr—N	see HMTZCR (2.203)
Co—N	(6), (III): excluding BISHUG (2.105)	1.932	1.932	0.023	1.920	1.943	67
Ni—N	(4, 6), (0, II): all	2.118	2.125	0.071	2.084	2.153	6	9
	(6), (II)	2.143	2.129	0.043	2.118	2.174	5
Cu—N	see PMPDCU (2.052)
Ru—N	see BUPMOO (2.099)
Pd—N	(4), (II)	2.020	2.020	0.021	2.001	2.035	6
Pt—N	(4, 6), (II–IV): all	2.132	2.171	0.076	2.038	2.188	6
	(6), (III, IV)	2.181	2.179	0.013	2.169	2.195	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.22.1 Ammonia (NH₃)								105
Cr—N	(6), (III)	2.069	2.069	0.008	2.063	2.076	5
Co—N	(6), (III)	1.965	1.963	0.021	1.953	1.974	119
Ni—N	(4, 6), (II): all	2.074	2.115	0.093	1.941	2.141	7	30
	(6), (II)	2.128	2.130	0.019	2.109	2.146	5
Cu—N	(4–6),(II)	1.987	1.988	0.017	1.977	1.996	11
Zn—N	see CAXPUM (2.036, 2.051)
Mo—N	see MEKTMO (2.217)
Ru—N	(6), (II, III): all	2.126	2.123	0.024	2.109	2.145	37
	(6), (II)	2.151	2.150	0.012	2.142	2.162	14
	(6), (III)	2.110	2.111	0.016	2.104	2.122	19
Rh—N	(4, 6), (I, III): all	2.114	2.120	0.018	2.111	2.124	7
	(4), (I)	2.120	2.121	0.007	2.113	2.126	6
Pd—N	see APDPZC (2.026, 2.038)
Re—N	see ATCTPR (2.253)
Os—N	see TCTPOS (2.136)
Pt—N	(4–6,^‡), (II–IV): all	2.050	2.048	0.021	2.036	2.059	102
	(4), (II)	2.049	2.046	0.017	2.035	2.060	40
	(6), (III, IV)	2.050	2.051	0.009	2.045	2.056	25
	(5), (II)	2.052	2.053	0.023	2.038	2.069	23
	(^‡), (-)	2.032	2.036	0.013	2.019	2.045	12

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.22.2 Primary amines [NH₂R, R = C(sp³)]
N—C		1.484	1.484	0.019	1.474	1.494	1577
Cr—N	(6), (III)	2.078	2.080	0.021	2.068	2.089	138
Mn—N	(5), (II)	2.198	2.199	0.007	2.192	2.204	6
Fe—N	(6, II): all picolylamine	2.067	2.030	0.070	2.019	2.084	15	30
	(6, II): excluding FEPICA	2.035	2.027	0.027	2.012	2.063	12
Co—N	(4–6), (II, III): all	1.966	1.964	0.025	1.952	1.977	716
	(6), (III)	1.965	1.964	0.021	1.952	1.976	710
Ni—N	(4–6, ^‡), (-): all	2.074	2.089	0.064	2.071	2.115	130	30
	(4), (II): excluding BIHFAZ, NETNIP02	1.917	1.918	0.008	1.912	1.922	16
	(4), (II): only BIHFAZ, NETNIP02	2.084	2.086	0.008	2.075	2.091	6
	(6), (II)	2.097	2.096	0.024	2.078	2.117	99
Cu—N	(4–6, ^‡), (-): all	2.019	2.013	0.039	1.996	2.030	274	12, 86
	(4), (II)	2.011	2.009	0.026	1.995	2.025	61
	(5), (-)	2.024	2.014	0.040	1.998	2.033	132	86
	(6), (II): excluding 3 > 2.150	2.014	2.016	0.023	1.997	2.029	62
Zn—N	(4–6), (II): all	2.114	2.102	0.065	2.063	2.152	51
	(5), (II)	2.064	2.063	0.034	2.043	2.074	18
	(6), (II)	2.152	2.139	0.054	2.103	2.206	30
Mo—N	(6–8), (II, IV–VI): all	2.290	2.271	0.067	2.237	2.355	13	30
	(6–8), (II, IV, V)	2.243	2.251	0.030	2.224	2.267	8
	(6), (VI)	2.364	2.362	0.023	2.343	2.387	5
Tc—N	(6), (V)	2.171	2.173	0.026	2.144	2.191	6
Ru—N	(6), (II, IV): all	2.123	2.120	0.025	2.108	2.141	27
Rh—N	(6), (III)	2.061	2.062	0.009	2.053	2.068	12	85
Pd—N	(4, 5), (II): all	2.037	2.041	0.022	2.027	2.050	42
Ag—N	see AGENPC10 (2.169, 2.171)
Cd—N	(6), (II)	2.291	2.292	0.013	2.279	2.298	13
Nd—N	all BILSIY	2.628	2.627	0.020	2.613	2.638	6
W—N	see BOWLUU (2.407), CACRIH (2.213)
Re—N	(6), (V)	2.164	2.161	0.018	2.149	2.179	8
Os—N	(6), (IV, VI)	2.128	2.114	0.037	2.109	2.155	5
Pt—N	(4–6, ^‡), (II, IV): all	2.049	2.048	0.030	2.034	2.065	107
	(4), (II)	2.043	2.046	0.026	2.033	2.061	65
	(6), (II, IV)	2.069	2.065	0.034	2.047	2.079	27
Au—N	see ENSPAU (2.119, 2.134)
Hg—N	see COKDUB (range 2.179–2.416)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.22.3 Primary amines [NH₂R, R = C(sp²)]
N—C		1.437	1.440	0.025	1.429	1.449	43
Co—N	(5, 6), (II, III): all	2.012	2.009	0.051	1.977	2.042	13
	(5, 6), (II)	2.016	2.014	0.009	2.008	2.025	4
	(6), (III)	2.010	2.001	0.062	1.947	2.066	9
Ni—N	see MAQUNI10 (2.057, 2.063)
Cu—N	(4–6, ^‡), (II): excluding BZBCUA (2.216)	2.036	2.027	0.028	2.012	2.066	5	12
Zn—N	(4–6), (II)	2.095	2.085	0.053	2.049	2.150	4
Mo—N	see ABTCMO (2.001, 2.009)
Ru—N	see CANBRU (2.213)
Rh—N	see BAYJAM (2.155), PRNRHD (2.324)
Pd—N	see SULPDC10 (2.055)
Cd—N	(5–7), (II)	2.402	2.423	0.039	2.359	2.435	9
Nd—N	see BABNAT (2.743)
Re—N	see ACANRE (2.246)
Pt—N	see BATLPT10 (2.103), XAXASP (2.074)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.22.4 Secondary amines [NHR₂, R = C(sp³)]
N—C		1.488	1.487	0.021	1.476	1.499	1718
Ti—N	see BUNKIE (2.284, 2.301)
V—N	see CAGSAE (2.328), CINKUF (2.150, 2.160, 2.328)
Cr—N	(6), (0, II, III): all	2.090	2.086	0.033	2.071	2.100	40
	(6), (II, III)	2.085	2.085	0.021	2.070	2.093	38
Fe—N	(6, 7), (II, III): all	2.158	2.164	0.078	2.133	2.181	44
	(6), (III)	2.142	2.157	0.062	2.125	2.179	40
	(7), (II)	2.316	2.306	0.042	2.283	2.360	4
Co—N	(6), (II, III): all	1.976	1.970	0.050	1.949	1.991	229
	(6), (II)	2.168	2.161	0.031	2.152	2.176	9
	(6), (III)	1.968	1.967	0.030	1.947	1.986	216
Ni—N	(4–6), (II): all	2.042	2.067	0.086	1.954	2.108	204	30
	(4), (II)	1.930	1.930	0.028	1.916	1.953	60
	(6), (II)	2.097	2.098	0.042	2.072	2.121	124
Cu—N	(4–6, ^‡), (II): all	2.034	2.026	0.056	2.008	2.048	166	12, 86
	(4), (II)	2.030	2.025	0.034	2.008	2.049	17
	(5), (II): all	2.043	2.029	0.067	2.010	2.055	97	86
	: excluding 5 > 2.23	2.029	2.027	0.032	2.008	2.049	92
	6, (II): all	2.022	2.022	0.027	2.002	2.048	35
Zn—N	(4–6), (II): all	2.143	2.162	0.079	2.066	2.214	17
	(4), (II): all MAMPZN	2.039	2.039	0.006	2.032	2.045	4
	(5), (II): all	2.188	2.200	0.051	2.155	2.219	10
Mo—N	(5–8), (0, II–VI)	2.271	2.259	0.054	2.219	2.329	32	81, 87
Tc—N	all BAPPIR	2.126	2.125	0.011	2.115	2.137	4
Ru—N	(6), (II, III): all	2.127	2.085	0.085	2.071	2.238	10	30
	(6), (III)	2.075	2.083	0.018	2.064	2.085	7
Rh—N	(4, 6), (I, III): all	2.116	2.094	0.084	2.044	2.201	14	30
	(4), (I)	2.202	2.202	0.036	2.163	2.236	6
	(6), (III)	2.051	2.051	0.032	2.019	2.084	8
Pd—N	(4, 6), (II, IV): all	2.043	2.053	0.035	2.007	2.060	28
	(4), (II)	2.041	2.047	0.036	2.003	2.059	25
Ag—N	(5, 6), (I): excluding TZTDAG01 (2.159, 2.162)	2.483	2.476	0.054	2.443	2.536	10
Cd—N	(4–7), (II): all	2.318	2.329	0.051	2.267	2.370	10
W—N	see CAPSOB (2.333, 2.338)
Re—N	(6), (I)	2.248	2.250	0.021	2.230	2.268	6
Pt—N	(4, 6), (II, IV): all	2.054	2.046	0.052	2.020	2.075	31
	(4), (II)	2.060	2.052	0.059	2.003	2.122	21
	(6), (IV)	2.049	2.048	0.013	2.036	2.063	8
Hg—N	see BUPSUA (2.275, 2.439), HGTXZO (2.724)
U—N	see SDAPOU20 (2.589)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
4.22.5 Secondary amines [NHR₂, R₂ ≠ C(sp³)₂]
N—C	R = C(sp²)	1.452	1.452	0.021	1.436	1.468	14
	R = C(sp³)	1.488	1.484	0.015	1.497	1.478	14
Ni—N	(4, 6), (II): all	2.070	2.090	0.084	2.018	2.143	10
	(6), (II)	2.105	2.091	0.045	2.066	2.156	8
Zn—N	see CAKGAW (2.213, 2.214)
Mo—N	see BESJOY (2.357, 2.379)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.22.6 Tertiary amines (NR₃, R = any C)
N—C		1.487	1.487	0.021	1.475	1.500	2246
Ti—N	(6), (IV)	2.296	2.294	0.025	2.273	2.317	6
V—N	(6, 7), (III–V)	2.277	2.279	0.056	2.262	2.294	12
Cr—N	(5, 6), (0, II, III): all	2.152	2.138	0.106	2.066	2.209	20
	(6), (0)	2.207	2.209	0.016	2.192	2.221	4
	(6), (III): excluding BILDIJ (2.355)	2.093	2.089	0.044	2.046	2.138	13
Mn—N	(4–6), (I–III): all	2.306	2.338	0.120	2.197	2.384	9
	(5, 6), (II)	2.393	2.354	0.076	2.341	2.465	5
Fe—N	(5–7), (II, III): all	2.215	2.199	0.112	2.090	2.317	36
	(5), (II): all	2.155	2.162	0.079	2.080	2.191	11	96
	(5–7), (III): all	2.241	2.292	0.115	2.099	2.319	25	30, 96
	(5–7), (III): Fe—N < 2.18	2.101	2.089	0.031	2.085	2.105	9
	(5–7), II: Fe—N > 2.26	2.321	2.316	0.044	2.294	2.338	16
Co—N	(4–6), (I–III): all	2.080	2.040	0.135	1.961	2.199	91	86
	(4), (II)	2.075	2.068	0.026	2.062	2.102	7
	(6), (II)	2.216	2.218	0.039	2.187	2.237	25
	(6), (III)	1.961	1.960	0.027	1.938	1.977	43
Ni—N	(4–6), (0–III): all	2.112	2.115	0.109	2.062	2.177	95
	(4), (II)	1.957	1.973	0.048	1.894	1.996	11
	(6), (II)	2.144	2.147	0.057	2.101	2.177	59
	(6), (III): all CEXHAO	1.924	1.926	0.012	1.912	1.939	7
Cu—N	(4–6, ^‡), (I, II): all	2.098	2.071	0.093	2.045	2.112	260	12, 86
	(4), (I)	2.139	2.135	0.053	2.099	2.178	44
	(4), (II)	2.057	2.055	0.039	2.045	2.073	35
	(5)	2.099	2.067	0.112	2.043	2.095	125	86
	(6): all	2.091	2.049	0.095	2.034	2.105	43	30, 86
	(6): short (<2.12)	2.046	2.042	0.028	2.021	2.062	34
	(6): long (>2.19)	2.260	2.244	0.056	2.213	2.299	9
Zn—N	(4–6), (II): excluding CMPORZ (2.530)	2.159	2.147	0.071	2.105	2.197	24
	(4)	2.111	2.106	0.031	2.086	2.143	11
	(5)	2.234	2.205	0.059	2.191	2.300	6
	(6): all	2.171	2.147	0.068	2.110	2.244	7
Mo—N	(5, 6, ^‡) (II–IV): all	2.372	2.387	0.094	2.273	2.450	33
	(^‡), (IV): clusters only	2.252	2.255	0.016	2.242	2.265	6
	(6), (II)	2.398	2.410	0.054	2.344	2.447	6
	(6), (IV)	2.419	2.409	0.046	2.382	2.462	5
	(6), (VI)	2.430	2.428	0.078	2.354	2.514	6	81
Tc—N	(6), (-)	2.196	2.200	0.029	2.170	2.220	5
Ru—N	see CIYTUZ01 (2.306)
Rh—N	(6), (I, III): all	2.087	2.083	0.066	2.032	2.152	9
	(6), (III)	2.050	2.052	0.040	2.020	2.086	6
Pd—N	(4, 5, ^‡), (-): all	2.111	2.098	0.052	2.097	2.147	66
	(4), (-)	2.110	2.093	0.053	2.077	2.145	61	81
Ag—N	(3, 4, ^‡), (I)	2.372	2.380	0.031	2.342	2.406	9
Cd—N	(5–8), (II)	2.437	2.428	0.074	2.379	2.499	18
La—N	see HETALA11 (2.804, 2.835)
Pr—N	see BIFYUK (2.696, 2.731)
Nd—N	see BILSIY (2.701, 2.717)
Sm—N	(9, 10), (III)	2.715	2.716	0.059	2.659	2.771	4
Eu—N	(7, 9), (-): excluding CEXHUL (2.899)	2.606	2.627	0.062	2.540	2.651	4
Gd—N	see BIFZEV (2.625, 2.677)
Dy—N	(8, 9), (-)	2.602	2.596	0.031	2.577	2.634	4
Er—N	see HENAEB (2.523, 2.561)
Yb—N	(8, 9), (-)	2.571	2.555	0.054	2.529	2.628	4
Lu—N	see CILCUV (2.588, 2.478, 2.468)
W—N	see CEPLUE (2.492, 2.325)
Re—N	see BOTFOF (2.326), COLWAB (2.242, 2.269)
Os—N	see CHDQOS (2.231)
Ir—N	(4, 6), (I, II): all	2.095	2.078	0.049	2.066	2.134	5
	(6), (III)	2.074	2.077	0.013	2.061	2.085	4
Pt—N	(4–6), (II): all	2.137	2.116	0.083	2.082	2.146	18	86
	(4), (II)	2.108	2.116	0.035	2.078	2.126	13
Hg—N	see CEFCUL (2.888)
U—N	see EMASOU10 (2.692)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
4.23.1 Borazines (see also 2.3.1)
V—N	see BOKXEE (2.218)
Cr—N	see BRNOCR (2.067, 2.069), BUZPIV (2.205, 2.211), EMABOB (2.133, 2.159)
Fe—N	see BEHLOP (2.090), BEMLAG10 (2.008), BUCZOO (2.012)
Ni—N	see CIDBOG (2.495)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.1.1.1 Oxo (terminal O)								106
V—O	(5–7), (-)	1.607	1.606	0.026	1.588	1.622	79	107
Cr—O	(4, 5), (-)	1.616	1.598	0.041	1.590	1.651	11	7
Nb—O	(5–7), (-)	1.720	1.731	0.030	1.695	1.745	17
Mo—O	(4–7), (-)	1.693	1.694	0.021	1.678	1.707	346	77, 108
Tc—O	(5–6), (-): all	1.676	1.660	0.051	1.632	1.743	14	30
	(5, 6), (-): not trans to O	1.647	1.652	0.022	1.626	1.664	10	44
	(6), (V): trans to O	1.749	1.751	0.006	1.743	1.754	4
W—O	(-), (-)	1.692	1.697	0.020	1.674	1.706	22
Re—O	(4–6), (-)	1.709	1.709	0.032	1.695	1.723	54	90
Os—O	(4–6), (-)	1.718	1.722	0.022	1.711	1.732	17	110
U—O	(6–8), (-)	1.763	1.762	0.026	1.748	1.776	161

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.1.1.2 Oxo (μ₂-O)								106
Ti—O	(5–8), (-)	1.820	1.824	0.028	1.794	1.841	44
V—O	see BIGVAO (1.697, 1.884; 1.694, 1.874), BUPCEU (1.763, 1.875)
Cr—O	see CEYBIR (1.812, 1.818), HMTCRC10 (1.764)
Fe—O	(4–7), (-)	1.794	1.779	0.065	1.770	1.791	22
	: excluding CEFVOY	1.775	1.774	0.017	1.769	1.787	20
Zr—O	(4, 8), (IV)	1.957	1.958	0.008	1.950	1.964	11
Nb—O	(6–8), (IV, V)	1.946	1.926	0.036	1.913	1.983	21
Mo—O	(5–7, ^‡), (-): excluding CABHIW	1.924	1.927	0.028	1.910	1.941	239
Tc—O	(6), (-)	1.914	1.914	0.008	1.907	1.923	6
Hf—O	see OXMCHF (1.941)
Ta—O	(6, 7), (V)	1.924	1.923	0.027	1.900	1.951	4
W—O	(5, 6, ^‡), (-)	1.916	1.920	0.023	1.899	1.933	64
Re—O	(6), (II–VII)	1.926	1.920	0.026	1.907	1.945	16
Os—O	(5, 6), (IV, VI)	1.859	1.830	0.061	1.811	1.922	5	87
U—O	see PAUELI10 (2.161, 2.197)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.1.1.3 Oxo (μ₃-O)
Ti—O	all CPTIOO	1.972	1.971	0.006	1.968	1.977	20
V—O		1.946	1.985	0.061	1.872	1.995	20	30
Cr—O		1.937	1.936	0.008	1.933	1.944	13
Mn—O	see OACPMN (1.942)
Fe—O	all COCNAJ	1.929	1.956	0.056	1.863	1.968	6
Co—O	see OXCFOR (2.039, 2.055, 2.114)
Nb—O		2.062	2.039	0.046	2.027	2.118	12	30
Mo—O		2.015	2.003	0.035	1.990	2.048	47
Ru—O	see BAHPEF (2.056, 2.067, 2.114)
Rh—O		1.959	1.965	0.040	1.920	1.996	6
W—O		1.994	1.999	0.019	1.981	2.007	28
U—O	see BIHCUQ (2.229, 2.231, 2.243)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
5.2.1.1 Hydroxy (terminal OH)
Cr—O	[including H⋯O(H)—Cr]	1.929	1.926	0.013	1.919	1.936	6
Co—O	see CHXPCO (1.895), HGXIMC (2.190)
Zn—O	see ACBZNM (2.268)
Mo—O		1.988	1.976	0.043	1.957	2.032	4
Re—O	see BAXJOZ (1.795)
Pt—O		2.006	2.002	0.017	1.992	2.023	9

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.2.1.2 Hydroxy (μ₂-OH)
V—O	see CINKUF (1.955, 1.968)
Cr—O	(6), (II, III)	1.959	1.960	0.023	1.946	1.972	55
Fe—O	(5, 6, ^‡), (III): dominated by COCNAJ	1.967	1.965	0.039	1.951	1.989	34
Co—O	(6), (III)	1.905	1.908	0.019	1.895	1.924	11
Cu—O	(4, 5, ^‡), (II)	1.918	1.913	0.029	1.897	1.931	55	111
Zr—O	see COSROR (2.091, 2.167)
Mo—O	(6–8), (III, IV)	2.061	2.081	0.068	2.040	2.098	10	87
Ru—O	(6,^‡), (II, III)	2.093	2.112	0.049	2.031	2.132	13	87
Rh—O	(6), (III)	2.110	2.108	0.046	2.090	2.135	10
Yb—O	see PCPHYB (2.188, 2.216)
Ta—O	see BUCLUG (2.024, 2.041)
Re—O	(6), (I, VII)	2.100	2.070	0.054	2.060	2.165	6	87
	(6), (VII)	2.065	2.065	0.006	2.059	2.070	4
Os—O	see CIRNUM (2.120, 2.133)
Ir—O	all BAHVAH	2.120	2.119	0.004	2.117	2.125	4
Pt—O	all HEPPTB	2.130	2.130	0.041	2.094	2.167	4
U—O	see BUFFUD (2.336, 2.346)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.2.1.3 Hydroxy (μ₃-OH)
Ni—O	all TACNIH10	2.087	2.091	0.011	2.079	2.096	7
Cu—O	(^‡), (II)	1.995	1.988	0.033	1.969	2.024	10
Zn—O	see ACBZNM (1.990, 2.089, 2.096)
Mo—O	all CHPMOC	2.100	2.074	0.067	2.055	2.172	12	30
Ru—O	(^‡), (-)	2.146	2.141	0.028	2.123	2.173	4
W—O	all DPEPOW	2.211	2.229	0.048	2.161	2.247	12
Re—O	see BALZUJ (2.210)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.3.1.1 Alkoxy [terminal O—C(sp³)]
O—C		1.426	1.427	0.030	1.411	1.443	287
Ti—O	(6–8), (IV)	1.847	1.855	0.055	1.812	1.883	6
V—O	see PRXHQV (1.774)
Cr—O	(4, 5), (III, IV)	1.816	1.824	0.045	1.773	1.855	5
Mn—O	see BOPWAE (1.838)
Fe—O	see LIBCRC (1.806, 1.829), MPORFE10 (1.815)
Co—O	(6), (-): dominated by (III)	1.921	1.931	0.026	1.897	1.939	9
Ni—O	see BIBSAG (1.853), FMPHNI (1.840, 1.842)
Cu—O	(4, 5), (II): excluding 1 > 2.46	1.899	1.908	0.025	1.875	1.917	17
Zr—O	(7, 8), (IV)	1.924	1.921	0.020	1.905	1.944	5
Nb—O	(6), (V)	1.869	1.877	0.048	1.818	1.910	15
Mo—O	(4–6, ^‡), (-)	1.911	1.908	0.046	1.885	1.935	114	15
Tc—O	see ASMETE (1.963, 1.936)
Rh—O	see INDRHA (2.081), INDRHB (2.013)
Ce—O	see FLMECE (2.196, 2.203, 2.230)
W—O		1.900	1.901	0.044	1.868	1.934	85
Re—O	(6), (V, VI)	1.890	1.886	0.028	1.869	1.901	8
Os—O	(5, 6), (VI)	1.914	1.896	0.047	1.873	1.970	8
Pt—O	(4, 6), (II, IV)	2.028	2.029	0.031	2.000	2.056	4
U—O	(7, 8), (IV, VI)	2.122	2.121	0.084	2.047	2.199	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.3.1.2 Alkoxy [μ₂-OC(sp²)]
O—C		1.433	1.429	0.029	1.410	1.455	42
Cr—O	(6), (I, II)	1.980	1.980	0.026	1.957	2.005	4
Fe—O	see BIGPOW (1.998, 1.948)
Cu—O	(4, 5, ^‡), (II)	1.929	1.934	0.018	1.918	1.944	20	111
Zn—O		1.958	1.969	0.027	1.929	1.975	4
Zr—O	all BUXLEL	2.156	2.158	0.026	2.130	2.180	6
Nb—O	all NBPMOX	2.149	2.151	0.023	2.127	2.170	4
Mo—O		2.094	2.105	0.054	2.032	2.154	12
Rh—O	see BUHTON (2.051, 2.063)
Pd—O	all BIJPAL	1.996	1.999	0.010	1.985	2.004	4
W—O		2.081	2.087	0.057	2.029	2.114	16
Re—O	all MXOXRE10	2.113	2.109	0.021	2.095	2.135	4
Pt—O	see MODIPT (2.040, 2.161)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.3.1.3 Alkoxy [μ₃-OC(sp³)]
O—C		1.445	1.441	0.026	1.429	1.459	49
Fe—O	see BOWCAR10 (1.985, 1.989, 1.941)
Co—O	(-), (II, III): all (many asymmetric)	2.044	2.091	0.104	1.911	2.135	20	30
	(-), (III): all are < 1.93	1.899	1.903	0.019	1.886	1.911	6
	(-), (II): all are > 2.02	2.106	2.101	0.042	2.082	2.143	14
Ni—O		2.066	2.062	0.035	2.032	2.084	18
Cu—O	(-), (I, II): all	2.147	1.986	0.260	1.959	2.422	68	30
	(-), (II): short (<2.12)	1.968	1.963	0.026	1.954	1.977	41
	(-), (II): long (>2.22)	2.518	2.540	0.116	2.428	2.596	21
Zn—O	all BOYTOY	2.017	2.064	0.017	2.056	2.086	12
Mo—O		2.186	2.166	0.049	2.154	2.221	13	111
Ru—O	see IPVRUB (2.127, 2.145, 2.210)
W—O	see HXETOW10 (2.174, 2.201, 2.160)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.3.2.1 Aryloxy (terminal OAr)^§
O—C¹		1.321	1.318	0.022	1.307	1.333	442
C¹—C²		1.410	1.411	0.018	1.399	1.422	888
C²—C³		1.394	1.393	0.026	1.375	1.411	890
C³—C⁴		1.381	1.379	0.024	1.367	1.394	890
Ti—O	(5, 6, 8), (III, IV): all	1.873	1.898	0.064	1.828	1.920	9
V—O	(5, 6), (IV, V): all	1.917	1.925	0.043	1.906	1.945	13
Cr—O	(6), (III)	1.921	1.924	0.007	1.914	1.926	6
Mn—O	(6), (III)	1.914	1.896	0.064	1.866	1.953	8
Fe—O	(4–6,^‡), (II, III)	1.913	1.905	0.043	1.882	1.937	66
Co—O	(4–6), (I–III): all	1.907	1.896	0.051	1.873	1.919	93	86
	(4), (II)	1.867	1.860	0.028	1.847	1.880	22
	(5), (II)	1.923	1.925	0.039	1.879	1.953	15
	(6), (II)	1.977	1.995	0.062	1.906	2.030	17	30
	(6), (III)	1.894	1.895	0.014	1.886	1.903	34
Ni—O	(4–6), (II): all	1.915	1.865	0.085	1.847	2.006	37	30
	(4), (II)	1.865	1.856	0.049	1.824	1.888	16
	(5), (II): excluding 2 > 1.97	1.848	1.849	0.007	1.842	1.853	8
	(6), (II)	2.023	2.023	0.021	2.005	2.045	11
Cu—O	(2–6), (I, II): all	1.908	1.898	0.039	1.887	1.927	89	111
	(4), (II)	1.893	1.892	0.015	1.884	1.900	48
	(5), (II)	1.920	1.918	0.034	1.892	1.940	25
	(6), (II)	1.940	1.943	0.022	1.928	1.957	12
Zn—O	see CPZHZN (1.953), MPZHZN (1.957), SALEZN (1.937)
Y—O	all BIRJUH	2.298	2.297	0.013	2.287	2.310	4
Zr—O	(8), (IV)	2.074	2.086	0.033	2.030	2.099	7
Mo—O	(4–6), (II–VI)	1.964	1.956	0.080	1.915	1.974	29	15
	(4–6), (III, IV)	1.927	1.926	0.026	1.902	1.954	11
Tc—O	see CEPHUA (1.987), COKZAD (1.949)
Ru—O	see CESNAP (2.080, 2.129)
Rh—O	(4, 6), (I, III)	2.035	2.035	0.010	2.024	2.041	7
Pd—O	(4), (II)	2.016	1.992	0.041	1.984	2.056	12
Ce—O	all CEZYUB	2.215	2.219	0.021	2.194	2.233	4
Ta—O	see BUNKAW (1.909), COLVII (1.836)
W—O	(5–7), (II, V, VI): all	1.955	1.936	0.063	1.919	1.962	18
	(5, 6) (V, VI)	1.935	1.931	0.031	1.916	1.956	16
Re—O	(6), (III–V)	1.971	1.975	0.021	1.951	1.992	8
Os—O	(6), (II)	1.988	1.987	0.016	1.973	2.005	5
Ir—O	see MICPIR10 (2.062, 2.050), SCLIRA10 (2.004)
Pt—O	(4), (II)	1.996	2.003	0.020	1.978	2.010	5
Th—O	(8, 9), (IV)	2.321	2.335	0.026	2.301	2.344	7
U—O	(7, 8), (VI)	2.235	2.234	0.023	2.213	2.238	7

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.3.2.2 Alkoxy/aryloxy [μ₂-OC(sp²)]
O—C		1.330	1.331	0.029	1.315	1.344	68
Ti—O	see CIGVET (2.041, 2.080), CLPHTI (1.911, 2.121)
V—O	see BUVNUB (1.963, 2.269)
Fe—O	(5, 6), (I, III)	2.009	2.003	0.048	1.965	2.057	6
Co—O	(6), (II)	2.077	2.085	0.062	2.016	2.130	14
Ni—O	(4, 6), (II): all	2.003	2.010	0.072	1.982	2.054	14
	(6), (II)	2.031	2.039	0.041	1.988	2.061	12
Cu—O	(3–6, ^‡), (I, II): all	2.021	1.977	0.145	1.923	2.069	78	30
	(4–6, ^‡), (II): short (<2.14)	1.956	1.949	0.055	1.916	1.985	58
	: long (>2.26)	2.357	2.348	0.067	2.299	2.413	10
Mo—O	see BCATMO (2.038, 2.324), PXTCMO10 (2.048, 2.052)
Ru—O	see CIYTUZ01 (2.203, 2.211)
Cd—O	see PYXCDC (2.306, 2.317)
Re—O	see PHCORE (2.152, 2.149)
Hg—O	see PHGMQU (2.161, 2.790)
U—O	all BIHCUQ	2.522	2.531	0.033	2.497	2.548	6

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
5.4.1 Ketones (terminal, η^l-OCR₂, R = any C)
O—C		1.264	1.264	0.022	1.252	1.272	24
V—O	see DPKEVB (2.081)
Fe—O	see MEOBFE (1.997)
Ru—O	see ACSNRU (2.194)
Cd—O	(7), (II): all CIHNEM	2.283	2.285	0.009	2.276	2.289	6
Er—O	(7), (III): all MPYOER10	2.280	2.299	0.044	2.252	2.321	7
Re—O	see PXBURE (2.159)
Ir—O	see CEXLUM (2.234, 2.220)
U—O	(6, 7), (VI)	2.336	2.341	0.059	2.228	2.396	6

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.4.2 Urea [terminal, η^l-OC(NH₂)₂]								112
O—C		1.266	1.266	0.014	1.254	1.277	52
C—N		1.330	1.328	0.016	1.319	1.342	103
Sc—O	(8), (III): all URSCNI	2.105	2.099	0.021	2.089	2.126	4
Ti—O	see TIUREA01 (2.014)
Cr—O	(6), (III): all $[\hbox{Cr}[\hbox{OC}(\hbox{NH}_2)_2]_6^{3+}]$	1.971	1.973	0.007	1.964	1.976	8
Mn—O	see BOPWEI (1.985)
Co—O	(6), (II)	2.091	2.094	0.010	2.081	2.099	4
Cu—O	(6), (II)	2.127	2.130	0.022	2.105	2.148	5	82
Zn—O	see UREAZN (2.147, 2.073, 2.091)
Mo—O	see BOHYEC (2.135)
Pr—O	see ACURLB (2.479, 2.504)
Nd—O	see CEFHOK (2.472, 2.500)
U—O	(7), (VI)	2.356	2.360	0.034	2.332	2.382	21

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
5.5.1.1 Formate (η¹-O₂CH)
(M)O—C		1.257	1.260	0.022	1.249	1.270	22
C—O		1.234	1.230	0.021	1.220	1.250	22
Fe—O	see FEFRMT (2.167)
Ni—O	see CESGAI10 (1.936)
Cu—O		1.966	1.956	0.030	1.949	1.988	5
Zn—O	see AQNCZN (2.089)
Y—O		2.343	2.364	0.046	2.296	2.370	7
Cd—O	see AFNICD (2.284)
U—O		2.352	2.328	0.052	2.309	2.408	5

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.5.1.2 Formate (η²-O₂CH)
O—C	(1.253, 1.261, 1.188)
Cu—O	see CAXMIX (2.352)
Y—O	see CAVYON (2.414, 2.425)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
5.5.1.3 Formate (μ₂-O₂CH)
O—C		1.262	1.263	0.014	1.251	1.272	47
Cr—O	(6), (II)	2.021	2.023	0.005	2.015	2.026	8
Co—O	see COKCIQ (1.912)
Mo—O	(5, 6), (II): all	2.121	2.123	0.013	2.106	2.132	12
Ru—O	(6, ^‡), (0, II/III): all	2.042	2.026	0.046	2.021	2.033	14
	(6), (II/III)	2.024	2.023	0.007	2.020	2.030	12
Rh—O	see BIHJOR10 (2.040, 2.049)
Re—O	(6, III) all CLFORE10	2.041	2.053	0.026	2.012	2.058	6
Os—O	all BIYXAI	2.167	2.166	0.008	2.159	2.174	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.5.2.1 Acetate (terminal, η¹-O₂CMe)
(M)O—C		1.264	1.263	0.028	1.252	1.280	46
C—O		1.236	1.237	0.031	1.229	1.250	46
C—C		1.512	1.510	0.026	1.499	1.523	46
Cr—O	see ACETCR (2.306)
Fe—O	see CIRDAI (1.898)
Co—O	(4–6), (II)	1.990	1.970	0.059	1.947	2.049	10	8
Ni—O	see ACATEN (2.063, 2.080), NIAQAC03 (2.072)
Cu—O	(4–6), (II)	1.957	1.957	0.015	1.949	1.966	10	12
Zn—O	(4), (II)	1.966	1.967	0.019	1.947	1.984	4
Mo—O	see PNPMOA (2.208)
Rh—O	see CESYAA (2.342)
Pd—O	see AMXPPD (2.115), SFSTPD (2.164)
Ag—O	see CELJEI (2.686)
Cd—O	see ETNTCD (2.281)
W—O	(6, 7), (0, IV): all	2.124	2.125	0.100	2.030	2.214	6	30
Os—O	see BOWLII (2.018, 2.032)
Au—O	see CILYAX (2.063)
Hg—O	see ACHPHG (2.454, 2.410), PHHGAC01 (2.083)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.5.2.2 Acetate (chelating, η²-O₂CMe)								113
O—C		1.257	1.263	0.024	1.244	1.270	66
C—C		1.496	1.497	0.025	1.480	1.514	34
Co—O	see BIHYEW (2.086, 2.109)
Cu—O	(6), (II)	2.306	2.259	0.208	2.172	2.477	6	12
Ru—O	see ACMPRU, ACTFIR, MPRUAC (in range 2.173–2.279)
Rh—O	see AZBRHA10 (2.240, 2.219), BOXNEH (2.235, 2.162)
Cd—O	see ACCDSC10, CDACET (in range 2.303–2.544)
Pr—O	see ACURLB (2.538, 2.536)
Nd—O	see CEFHOK (2.527, 2.516)
Sm—O	see BEDZAL (2.513, 2.421)
Gd—O	see ACAQGD (in range 2.427–2.484)
Re—O	see ACTPRE (2.233, 2.197)
Os—O	see BOWLII (2.169, 2.127)
Hg—O	see ETACHG, TBPAHG10 (in range 2.244–2.666)
U—O	(7, 8), (VI): all	2.467	2.465	0.025	2.452	2.484	20

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.5.2.3 Acetate (μ₂-O₂CMe)
O—C		1.263	1.263	0.019	1.255	1.273	373
C—C		1.509	1.507	0.023	1.495	1.524	187
Cr—O	(5, 6), (II): all Cr $[\qbond]$ Cr	2.010	2.007	0.014	2.001	2.021	26	7
Co—O		1.927	1.926	0.014	1.915	1.941	6	8
Ni—O	see BAPHAB (2.033, 2.052)
Cu—O	(6), (II)	1.971	1.970	0.013	1.963	1.980	38	12
Mo—O	(5–7), (II–IV)	2.110	2.110	0.021	2.096	2.122	97
Tc—O	(5, 6), (II, III)	2.068	2.066	0.009	2.060	2.072	10
Ru—O	(6), (II, III)	2.036	2.020	0.033	2.013	2.062	22
Rh—O	(5, 6), (I–III)	2.038	2.035	0.025	2.026	2.046	97	83, 86
Pd—O	(5, 6), (I, II)	2.095	2.106	0.051	2.050	2.127	18
W—O	(6, 7), (II–IV)	2.092	2.089	0.029	2.072	2.111	22
Re—O	(5, 6), (III)	2.025	2.025	0.009	2.015	2.031	10
Os—O	see CESXUT, COHNUI (in range 2.005–2.223)
Pt—O	(6), (II): all	2.087	2.117	0.081	2.004	2.161	18	30
	: long (>2.075)	2.155	2.160	0.026	2.141	2.175	10
	: short (<2.025)	2.003	2.003	0.016	1.993	2.016	8

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.5.3.1 Alkylcarboxylates [terminal, η¹-O₂CC(sp³)]
(M)O—C		1.278	1.279	0.021	1.266	1.291	769
C—O		1.234	1.233	0.017	1.224	1.244	768
C—C		1.521	1.521	0.019	1.510	1.532	768
Ti—O	(6), (IV)	2.000	1.983	0.043	1.967	2.015	15
V—O	(6, 7), (III-V): all	2.019	2.006	0.042	1.991	2.035	36
	(6), (IV, V): excluding BUPCIY	2.002	2.003	0.017	1.990	2.010	23
Cr—O	(5, 6), (III, V): all	1.963	1.963	0.019	1.952	1.975	52	8
	(6), (III)	1.965	1.965	0.016	1.954	1.975	50
Mn—O	(6), (I–III): all	2.059	2.040	0.121	1.913	2.165	35
	(6), (II)	2.161	2.164	0.022	2.146	2.180	15
	(6), (III): all	1.974	1.913	0.114	1.903	2.013	17	86
	: excluding 2 > 2.23	1.937	1.909	0.050	1.902	1.998	15	86
Fe—O	(6, 7), (II, III): all	2.033	2.038	0.069	1.974	2.094	40
	(6), (III)	2.018	2.012	0.057	1.971	2.048	15
	(7), (III)	2.041	2.046	0.068	1.976	2.099	22
Co—O	(4–6), (II, III): all	1.938	1.911	0.071	1.896	1.942	195	8, 86
	(4), (II)	1.966	1.955	0.022	1.948	1.989	10
	(6), (II)	2.088	2.075	0.050	2.062	2.097	26
	(6), (III)	1.906	1.904	0.019	1.894	1.918	153
Ni—O	(4–6), (II, III): all	2.051	2.055	0.056	2.038	2.087	72
	(6), (II)	2.065	2.059	0.034	2.044	2.089	66
Cu—O	(4–6), (II, III): all	2.015	1.961	0.145	1.946	1.982	123	86, 114
	(4), (II)	1.948	1.947	0.026	1.931	1.964	25
	(5), (II): all	1.991	1.957	0.108	1.947	1.976	44	86
	: excluding 4 > 2.2	1.960	1.952	0.036	1.945	1.973	40
	(6), (II): all	2.074	1.977	0.184	1.957	2.205	51	30
	: short (<2.14)	1.962	1.967	0.024	1.947	1.978	36
	: long (>2.2)	2.342	2.351	0.106	2.303	2.401	15
Zn—O	(4–6), (II): all	2.038	2.050	0.059	1.978	2.079	29
	(4), (II)	1.946	1.952	0.022	1.923	1.963	4
	(5), (II)	2.018	1.997	0.059	1.967	2.080	8
	(6), (II)	2.070	2.071	0.034	2.048	2.092	17
Nb—O	see CNBPAC (2.161)
Mo—O	(5–8), (0–VI): all	2.130	2.118	0.063	2.093	2.151	38
Tc—O	(6), (-): all	2.050	2.025	0.070	2.011	2.063	8	86
	: excluding PCLTCA10 (2.215)	2.027	2.019	0.023	2.009	2.036	7
Ru—O	(6), (II)	2.091	2.095	0.014	2.086	2.102	8
Rh—O	(6), (III)	2.023	2.027	0.018	2.003	2.038	9
Pd—O	(4, 5), (II)	2.023	2.019	0.024	2.006	2.029	16
Cd—O	(6, 7), (II)	2.372	2.358	0.048	2.338	2.389	8
La—O	(10), (III)	2.503	2.497	0.019	2.486	2.526	6
Ce—O	(9), (III)	2.483	2.480	0.021	2.472	2.489	7
Pr—O	(9), (III): all BIFYUK	2.458	2.447	0.027	2.441	2.484	4
Nd—O	see ODACND (2.428)
Sm—O	(9), (III): all NSMEDT02	2.421	2.421	0.021	2.400	2.441	4
Eu—O	(9), (III)	2.394	2.395	0.096	2.317	2.470	5
Gd—O	(9), (III): all BIFZEV	2.399	2.395	0.022	2.381	2.421	4
Dy—O	(8, 9), (III)	2.363	2.365	0.064	2.295	2.415	8
Er—O	see HENAEB (2.240, 2.262, 2.265)
Yb—O	(8, 9), (III)	2.286	2.282	0.035	2.252	2.308	10
W—O	see CIFNIO (2.132)
Os—O	see BABWAC (2.038), FATBOS10 (2.207)
Ir—O	(6), (III)	2.066	2.055	0.032	2.042	2.093	6
Pt—O	(4, 6), (II, IV)	2.031	2.014	0.040	2.003	2.045	13
Hg—O	see FAHGME10 (2.064), PHGTFA (2.121)
Th—O	(9, 10), (IV)	2.402	2.402	0.012	2.393	2.413	5
U—O	(7), (VI)	2.356	2.359	0.032	2.325	2.366	7

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
5.5.3.2 Alkylcarboxylates [chelating, η²-O₂CC(sp³)]
O—C		1.256	1.256	0.013	1.246	1.263	44
C—C		1.516	1.521	0.024	1.501	1.529	22
Ti—O	(8), (IV)	2.163	2.163	0.005	2.161	2.166	6
Co—O	see BIYHOG (2.145, 2.223)
Cu—O	see CEJPEM (2.528, 2.037)
Zn—O	(6), (II)	2.205	2.191	0.072	2.162	2.244	6
Mo—O	see FAMPMO (2.296, 2.338)
Cd—O	see ABPENC (2.262, 2.716), BAYDIO (2.378, 2.350)
Nd—O	see BODZEZ (2.535, 2.510)
Sm—O	see BOTWUC (2.495, 2.455; 2.495, 2.585)
U—O	see BIMAOU10 (2.526, 2.578)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.5.3.3 Alkylcarboxylates μ₂-O₂CC(sp³)]
O—C		1.258	1.257	0.020	1.246	1.270	434
C—C		1.519	1.519	0.026	1.504	1.536	222
Cr—O	(6), (II)	2.018	2.017	0.003	2.015	2.021	5
Cu—O	(6), (-)	1.966	1.968	0.014	1.956	1.975	95
Nb—O	all CIPNEU	2.151	2.145	0.014	2.141	2.163	10
Mo—O	(5, 6, ^‡), (-)	2.114	2.114	0.018	2.104	2.128	126
Ru—O	(6), (-)	2.134	2.132	0.009	2.128	2.142	8
Rh—O	(6), (-)	2.035	2.034	0.010	2.029	2.041	90	115
Pd—O	all BXCAPD	2.040	2.039	0.022	2.021	2.061	4
Cd—O	all CIFGON	2.266	2.259	0.020	2.251	2.289	8
Nd—O	all CIGRAL	2.422	2.422	0.018	2.406	2.439	4
W—O	(5, 6, ^‡)	2.092	2.091	0.016	2.082	2.103	66
Re—O	see OCPPRE (2.093, 2.097)
Os—O	(6), (III)	2.014	2.015	0.010	2.007	2.021	8

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.5.4.1 Carboxylates [η¹-O₂CC(sp²)]
(M)O—C		1.277	1.277	0.017	1.266	1.288	74
C—O		1.234	1.239	0.015	1.227	1.247	73
C—C(sp²)		1.508	1.507	0.014	1.499	1.513	74
V—O	see BIGFAY01 (1.896, 1.912)
Cr—O	see CAKCIA (1.946, 1.958)
Mn—O	see ABZAMN (2.187), ZEGPEG (2.111)
Co—O	see BELLEJ (2.130), CEBDIW (2.102), CUCOES (1.996), FSCUCO (1.941, 1.954)
Ni—O	(4, 6), (II): all	2.049	2.053	0.084	1.984	2.123	14
	(6), (II): mononuclear	2.100	2.118	0.044	2.053	2.135	9
Cu—O	(4–6, ^‡), (II): all	1.992	1.947	0.170	1.930	1.967	38	86
	(4), (II)	1.927	1.934	0.032	1.896	1.951	13
	(5), (II)	1.953	1.950	0.027	1.937	1.967	17
	(6), (II): excluding 3 > 2.45	1.964	1.954	0.041	1.931	2.007	4
Zn—O	(4, 6), (II)	2.033	2.010	0.053	1.989	2.090	5
Cd—O	see CITDEO (2.253)
Sm—O	see COSLEB (2.273), SALASM10 (2.488)
Er—O	See COSLIF (2.198)
Au—O	see CIYMEC (2.073, 2.074)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
5.5.4.2 Carboxylates [chelating, η²-O₂CC(sp²)]
O—C		1.266	1.265	0.019	1.253	1.278	39
C—C		1.481	1.482	0.022	1.474	1.493	20
Ti—O	all BUCBEG	2.148	2.150	0.009	2.138	2.155	4
Cu—O	see MESACV (1.976, 2.596)
Ru—O	see BAWZUU (2.118), BZCPRU (2.166, 2.130)
Cd—O	(7), (II): excluding CDMALD	2.409	2.427	0.058	2.351	2.445	10
La—O	see ALANIC (2.568, 2.646)
Nd—O	see BABNAT (2.529, 2.517), COSLAX (2.559, 2.512)
Sm—O	see COSLEB (2.467, 2.521), SMNICD (2.486, 2.567)
Dy—O	see AMAQDY (2.353, 2.517; 2.418, 2.502)
U—O	see BAWRIA (2.452, 2.543)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.5.4.3 Carboxylates [μ₂-O₂CC(sp²)]
O—C		1.267	1.267	0.018	1.252	1.280	97
C—C		1.493	1.492	0.024	1.476	1.508	49
Co—C	(6), (II): excluding PYMCXC	2.037	2.030	0.021	2.020	2.056	8	8
Cu—O	(4–6, ^‡), (I, II)	1.972	1.972	0.016	1.964	1.979	28
Zn—O	see ACBZNM (1.979, 2.018)
Mo—O	(5, 6), (II, III)	2.110	2.107	0.017	2.099	2.119	22
Rh—O	(6), (II)	2.038	2.036	0.011	2.027	2.050	16
W—O	(5), (II)	2.079	2.079	0.012	2.070	2.087	12
Re—O	(5, 6), (II)	2.015	2.016	0.010	2.006	2.025	8

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
5.5.5.1 Carbamates (chelating, η²-O₂CNR₂)
O—C		1.297	1.298	0.002	1.296	1.299	4
C—N	(1.298, 1.319)
N—C		1.462	1.457	0.011	1.456	1.473	4
Ta—O	all BOBXUL	2.131	2.131	0.018	2.114	2.147	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.5.6.1 O-Thiocarbamates [terminal, η¹-OC(S)NR₂] (see also 9.6.2.1)
(None)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
5.5.6.2 Thiocarbamates (chelating, η²-OSCNR₂) (see also 9.6.2.2)
O—S		1.274	1.274	0.010	1.267	1.281	15
S—C		1.728	1.731	0.009	1.725	1.733	15
C—N		1.336	1.338	0.014	1.325	1.345	15
N—C	excluding 1 > 1.6	1.478	1.474	0.027	1.461	1.496	29
Ti—O	see EMTCTJ (2.088, 2.077, 2.075)
Co—O	see TMTCPC (2.157)
Zr—O	see BUWMAH (2.249), EMTCZR (2.180, 2.200)
U—O		2.408	2.402	0.040	2.381	2.439	5

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.5.7.1 O-Thiocarboxylates [terminal, η¹-OC(S)R] (see also 9.5.2.1)
(None)

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
5.5.7.2 Thiocarboxylates (chelating, η²-OSCR) (see also 9.5.2.2)
O—C		1.236	1.246	0.035	1.234	1.255	9
S—C		1.705	1.702	0.012	1.698	1.716	9
C—C		1.521	1.522	0.025	1.501	1.531	9
Ni—O	(6), (II)	2.142	2.135	0.035	2.119	2.171	9

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n
5.5.7.3 Thiocarboxylates (μ₂-OSCR) (see also 9.5.2.3)
O—C		1.255	1.255	0.025	1.239	1.267	15
S—C		1.694	1.696	0.018	1.681	1.703	15
C—C		1.510	1.501	0.028	1.487	1.535	15
Mn—O	(7), (II)	2.315	2.313	0.036	2.283	2.342	8
Rh—O	see TACDRH10 (2.099, 2.114)
Ag—O	see CEFMIJ (2.510)
Eu—O	all BOTVIP10	2.511	2.508	0.032	2.483	2.541	4

Bond	Substructure (coordination number, oxidation state, comment)	d	m	σ	q_l	q_u	n	Note^†
5.6.1.1 Oxalate [chelating, η²(O₂C)₂]
(M)O—C		1.279	1.279	0.015	1.269	1.288	222
C—C		1.546	1.546	0.018	1.536	1.556	111
C—O		1.224	1.224	0.015	1.216	1.234	222
Ti—O	(6–8), (III, IV): all	2.041	2.031	0.054	1.992	2.086	30	81
V—O	(5, 6), (IV, V): all	2.083	2.036	0.090	2.015	2.164	18	81, 86
	: short (<2.1)	2.020	2.022	0.021	2.006	2.036	11	44
Cr—O	(6), (III)	1.969	1.975	0.019	1.959	1.981	24
Mn—O	(6), (III): all ZZZCCG10	2.000	2.018	0.077	1.911	2.074	6
Co—O	(6), (III)	1.911	1.912	0.011	1.903	1.920	22
Cu—O	(4–6), (II)	1.951	1.949	0.018	1.934	1.964	29
Y—O	(8), (III): all CIBZAO	2.335	2.340	0.018	2.329	2.344	6
Zr—O	(8), (IV)	2.202	2.195	0.034	2.183	2.219	10
Mo—O	(6, 7, ^‡), (-)	2.119	2.101	0.038	2.092	2.140	22
Rh—O	(6), (III): all CAZCIP	2.021	2.021	0.015	2.006	2.037	6
Nd—O	all CICBOF	2.474	2.457	0.042	2.448	2.518	4
Gd—O	all CICBUL	2.429	2.406	0.055	2.395	2.485	4
Er—O	(8), (III): all CIBYOB	2.333	2.336	0.011	2.321	2.342	6
Hf—O	(8), (IV): all KOXHFP10	2.190	2.184	0.022	2.171	2.211	8
Re—O	(6), (IV): all KXOXRE	2.063	2.060	0.029	2.038