In IT (1935) only the b axis was considered as the unique axis. In IT (1952) two choices were given: the c-axis setting was called the `first setting' and the b-axis setting was designated the `second setting'.
To avoid the presence of two standard space-group symbols side by side, in the present tables only one standard short symbol has been chosen, that conforming to the long-lasting tradition of the b-axis unique (cf. Sections 2.2.4
and 2.2.16
). However, for reasons of rigour and completeness, in Table 4.3.2.1 the full symbols are given not only for the c-axis and the b-axis settings but also for the a-axis setting. Thus, Table 4.3.2.1 has six columns which in pairs refer to these three settings. In the headline, the unique axis of each setting is underlined.
No. of space group
|
Schoenflies symbol
|
Hermann–Mauguin symbol for all settings of the same unit cell
|
1
|
|
P
1
|
2
|
|
|
No. of space group
|
Schoenflies symbol
|
Standard short Hermann–Mauguin symbol
|
Extended Hermann–Mauguin symbols for various settings and cell choices
|
|
abc
|
|
|
|
|
|
Unique axis b
|
|
|
abc
|
|
|
|
Unique axis c
|
|
|
|
|
a
bc
|
|
Unique axis a
|
3
|
|
P
2
|
P
121
|
P
121
|
P
112
|
P
112
|
P
211
|
P
211
|
|
4
|
|
|
|
|
|
|
|
|
|
5
|
|
C
2
|
|
|
|
|
|
|
Cell choice 1
|
|
|
|
|
|
|
|
|
|
Cell choice 2
|
|
|
|
|
|
|
|
|
|
Cell choice 3
|
6
|
|
Pm
|
P
1m1
|
P
1m1
|
P
11m
|
P
11m
|
Pm
11
|
Pm
11
|
|
7
|
|
Pc
|
P
1c1
|
P
1a1
|
P
11a
|
P
11b
|
Pb
11
|
Pc
11
|
Cell choice 1
|
|
|
|
P
1n1
|
P
1n1
|
P
11n
|
P
11n
|
Pn
11
|
Pn
11
|
Cell choice 2
|
|
|
|
P
1a1
|
P
1c1
|
P
11b
|
P
11a
|
Pc
11
|
Pb
11
|
Cell choice 3
|
8
|
|
Cm
|
|
|
|
|
|
|
Cell choice 1
|
|
|
|
|
|
|
|
|
|
Cell choice 2
|
|
|
|
|
|
|
|
|
|
Cell choice 3
|
9
|
|
Cc
|
|
|
|
|
|
|
Cell choice 1
|
|
|
|
|
|
|
|
|
|
Cell choice 2
|
|
|
|
|
|
|
|
|
|
Cell choice 3
|
10
|
|
P
2/m
|
|
|
|
|
|
|
|
11
|
|
|
|
|
|
|
|
|
|
12
|
|
C
2/m
|
|
|
|
|
|
|
Cell choice 1
|
|
|
|
|
|
|
|
|
|
Cell choice 2
|
|
|
|
|
|
|
|
|
|
Cell choice 3
|
13
|
|
P
2/c
|
|
|
|
|
|
|
Cell choice 1
|
|
|
|
|
|
|
|
|
|
Cell choice 2
|
|
|
|
|
|
|
|
|
|
Cell choice 3
|
14
|
|
|
|
|
|
|
|
|
Cell choice 1
|
|
|
|
|
|
|
|
|
|
Cell choice 2
|
|
|
|
|
|
|
|
|
|
Cell choice 3
|
15
|
|
C
2/c
|
|
|
|
|
|
|
Cell choice 1
|
|
|
|
|
|
|
|
|
|
Cell choice 2
|
|
|
|
|
|
|
|
|
|
Cell choice 3
|
No. of space group
|
Schoenflies symbol
|
Standard full Hermann–Mauguin symbol abc
|
Extended Hermann–Mauguin symbols for the six settings of the same unit cell
|
abc
(standard)
|
|
cab
|
|
bca
|
|
16
|
|
P
222
|
P
222
|
P
222
|
P
222
|
P
222
|
P
222
|
P
222
|
17
|
|
|
|
|
|
|
|
|
18
|
|
|
|
|
|
|
|
|
19
|
|
|
|
|
|
|
|
|
20
|
|
|
|
|
|
|
|
|
21
|
|
C222
|
|
|
|
|
|
|
22
|
|
F222
|
|
|
|
|
|
|
23
|
|
I
222
|
|
|
|
|
|
|
24
|
|
|
|
|
|
|
|
|
25
|
|
Pmm
2
|
Pmm
2
|
Pmm
2
|
P
2mm
|
P
2mm
|
Pm
2m
|
Pm
2m
|
26
|
|
|
|
|
|
|
|
|
27
|
|
Pcc
2
|
Pcc
2
|
Pcc
2
|
P
2aa
|
P
2aa
|
Pb
2b
|
Pb
2b
|
28
|
|
Pma
2
|
Pma
2
|
Pbm
2
|
P
2mb
|
P
2cm
|
Pc
2m
|
Pm
2a
|
29
|
|
|
|
|
|
|
|
|
30
|
|
Pnc
2
|
Pnc
2
|
Pcn
2
|
P
2na
|
P
2an
|
Pb
2n
|
Pn
2b
|
31
|
|
|
|
|
|
|
|
|
32
|
|
Pba
2
|
Pba
2
|
Pba
2
|
P
2cb
|
P
2cb
|
Pc
2a
|
Pc
2a
|
33
|
|
|
|
|
|
|
|
|
34
|
|
Pnn
2
|
Pnn
2
|
Pnn
2
|
P
2nn
|
P
2nn
|
Pn
2n
|
Pn
2n
|
35
|
|
Cmm
2
|
|
|
|
|
|
|
36
|
|
|
|
|
|
|
|
|
37
|
|
Ccc
2
|
|
|
|
|
|
|
38
|
|
Amm
2
|
|
|
|
|
|
|
39†
|
|
Aem
2
|
|
|
|
|
|
|
40
|
|
Ama
2
|
|
|
|
|
|
|
41†
|
|
Aea
2
|
|
|
|
|
|
|
42
|
|
Fmm
2
|
|
|
|
|
|
|
43
|
|
Fdd
2
|
|
|
|
|
|
|
44
|
|
Imm
2
|
|
|
|
|
|
|
45
|
|
Iba
2
|
|
|
|
|
|
|
46
|
|
Ima
2
|
|
|
|
|
|
|
47
|
|
|
Pmmm
|
Pmmm
|
Pmmm
|
Pmmm
|
Pmmm
|
Pmmm
|
48
|
|
|
Pnnn
|
Pnnn
|
Pnnn
|
Pnnn
|
Pnnn
|
Pnnn
|
49
|
|
|
Pccm
|
Pccm
|
Pmaa
|
Pmaa
|
Pbmb
|
Pbmb
|
50
|
|
|
Pban
|
Pban
|
Pncb
|
Pncb
|
Pcna
|
Pcna
|
51
|
|
|
Pmma
|
Pmmb
|
Pbmm
|
Pcmm
|
Pmcm
|
Pmam
|
52
|
|
|
Pnna
|
Pnnb
|
Pbnn
|
Pcnn
|
Pncn
|
Pnan
|
53
|
|
|
Pmna
|
Pnmb
|
Pbmn
|
Pcnm
|
Pncm
|
Pman
|
54
|
|
|
Pcca
|
Pccb
|
Pbaa
|
Pcaa
|
Pbcb
|
Pbab
|
55
|
|
|
Pbam
|
Pbam
|
Pmcb
|
Pmcb
|
Pcma
|
Pcma
|
56
|
|
|
Pccn
|
Pccn
|
Pnaa
|
Pnaa
|
Pbnb
|
Pbnb
|
57
|
|
|
Pbcm
|
Pcam
|
Pmca
|
Pmab
|
Pbma
|
Pcmb
|
58
|
|
|
Pnnm
|
Pnnm
|
Pmnn
|
Pmnn
|
Pnmn
|
Pnmn
|
59
|
|
|
Pmmn
|
Pmmn
|
Pnmm
|
Pnmm
|
Pmnm
|
Pmnm
|
60
|
|
|
Pbcn
|
Pcan
|
Pnca
|
Pnab
|
Pbna
|
Pcnb
|
61
|
|
|
Pbca
|
Pcab
|
Pbca
|
Pcab
|
Pbca
|
Pcab
|
62
|
|
|
Pnma
|
Pmnb
|
Pbnm
|
Pcmn
|
Pmcn
|
Pnam
|
63
|
|
|
|
|
|
|
|
|
64†‡
|
|
|
|
|
|
|
|
|
65
|
|
|
|
|
|
|
|
|
66
|
|
|
|
|
|
|
|
|
67†‡
|
|
|
|
|
|
|
|
|
68†
|
|
|
|
|
|
|
|
|
69
|
|
|
|
|
|
|
|
|
70
|
|
|
Fddd
|
Fddd
|
Fddd
|
Fddd
|
Fddd
|
Fddd
|
71
|
|
|
|
|
|
|
|
|
72
|
|
|
|
|
|
|
|
|
73
|
|
|
|
|
|
|
|
|
74‡
|
|
|
|
|
|
|
|
|
No. of space group
|
Schoen-flies symbol
|
Hermann–Mauguin symbols for standard cell P or I
|
Multiple cell C or F
|
Short
|
Extended
|
Short
|
Extended
|
75
|
|
P
4
|
|
C
4
|
|
76
|
|
|
|
|
|
77
|
|
|
|
|
|
78
|
|
|
|
|
|
79
|
|
I
4
|
|
F
4
|
|
80
|
|
|
|
|
|
81
|
|
|
|
|
|
82
|
|
|
|
|
|
83
|
|
|
|
|
|
84
|
|
|
|
|
|
85
|
|
|
|
|
|
86
|
|
|
|
|
|
87
|
|
|
|
|
|
88
|
|
|
|
|
|
89
|
|
P
422
|
|
C
422
|
|
90
|
|
|
|
|
|
91
|
|
|
|
|
|
92
|
|
|
|
|
|
93
|
|
|
|
|
|
94
|
|
|
|
|
|
95
|
|
|
|
|
|
96
|
|
|
|
|
|
97
|
|
I
422
|
|
F
422
|
|
98
|
|
|
|
|
|
99
|
|
P
4mm
|
|
C
4mm
|
|
100
|
|
P
4bm
|
|
|
|
101
|
|
|
|
|
|
102
|
|
|
|
|
|
103
|
|
P
4cc
|
|
C
4cc
|
|
104
|
|
P
4nc
|
|
|
|
105
|
|
|
|
|
|
106
|
|
|
|
|
|
107
|
|
I
4mm
|
|
F
4mm
|
|
108
|
|
I
4cm
|
|
F
4mc
|
|
109
|
|
|
|
|
|
110
|
|
|
|
|
|
111
|
|
|
|
|
|
112
|
|
|
|
|
|
113
|
|
|
|
|
|
114
|
|
|
|
|
|
115
|
|
|
|
|
|
116
|
|
|
|
|
|
117
|
|
|
|
|
|
118
|
|
|
|
|
|
119
|
|
|
|
|
|
120
|
|
|
|
|
|
121
|
|
|
|
|
|
122
|
|
|
|
|
|
123
|
|
|
|
|
|
124
|
|
|
|
|
|
125
|
|
|
|
|
|
126
|
|
|
|
|
|
127
|
|
|
|
|
|
128
|
|
|
|
|
|
129
|
|
|
|
|
|
130
|
|
|
|
|
|
131
|
|
|
|
|
|
132
|
|
|
|
|
|
133
|
|
|
|
|
|
134
|
|
|
|
|
|
135
|
|
|
|
|
|
136
|
|
|
|
|
|
137
|
|
|
|
|
|
138
|
|
|
|
|
|
139
|
|
|
|
|
|
140
|
|
|
|
|
|
141
|
|
|
|
|
|
142
|
|
|
|
|
|
No. of space group
|
Schoen-flies symbol
|
Hermann-Mauguin symbols for standard cell P or R
|
Triple cell H
|
Short
|
Full
|
Extended
|
143
|
|
P
3
|
|
|
H
3
|
144
|
|
|
|
|
|
145
|
|
|
|
|
|
146
|
|
R
3
|
|
|
|
147
|
|
|
|
|
|
148
|
|
|
|
|
|
149
|
|
P
312
|
|
|
H
321
|
150
|
|
P
321
|
|
|
H
312
|
151
|
|
|
|
|
|
152
|
|
|
|
|
|
153
|
|
|
|
|
|
154
|
|
|
|
|
|
155
|
|
R
32
|
|
|
|
156
|
|
P
3m1
|
|
|
H
31m
|
157
|
|
P
31m
|
|
|
H
3m1
|
158
|
|
P
3c1
|
|
|
H
31c
|
159
|
|
P
31c
|
|
|
H
3c1
|
160
|
|
R
3m
|
|
|
|
161
|
|
R
3c
|
|
|
|
162
|
|
|
|
|
|
163
|
|
|
|
|
|
164
|
|
|
|
|
|
165
|
|
|
|
|
|
166
|
|
|
|
|
|
167
|
|
|
|
|
|
No. of space group
|
Schoen-flies symbol
|
Hermann–Mauguin symbols for standard cell P
|
Triple cell H
|
Short
|
Full
|
Extended
|
168
|
|
P
6
|
|
|
H
6
|
169
|
|
|
|
|
|
170
|
|
|
|
|
|
171
|
|
|
|
|
|
172
|
|
|
|
|
|
173
|
|
|
|
|
|
174
|
|
|
|
|
|
175
|
|
P
6/m
|
|
|
H
6/m
|
176
|
|
|
|
|
|
177
|
|
P
622
|
|
|
H
622
|
178
|
|
|
|
|
|
179
|
|
|
|
|
|
180
|
|
|
|
|
|
181
|
|
|
|
|
|
182
|
|
|
|
|
|
183
|
|
P
6mm
|
|
|
H
6mm
|
184
|
|
P
6cc
|
|
|
H
6cc
|
185
|
|
|
|
|
|
186
|
|
|
|
|
|
187
|
|
|
|
|
|
188
|
|
|
|
|
|
189
|
|
|
|
|
|
190
|
|
|
|
|
|
191
|
|
|
|
|
|
192
|
|
|
|
|
|
193
|
|
|
|
|
|
194
|
|
|
|
|
|
No. of space group
|
Schoenflies symbol
|
Hermann–Mauguin symbols
|
Short
|
Full
|
Extended§
|
195
|
|
P
23
|
|
|
196
|
|
F
23
|
|
|
197
|
|
I
23
|
|
|
198
|
|
|
|
|
199
|
|
|
|
|
200
|
|
|
|
|
201
|
|
|
|
|
202
|
|
|
|
|
203
|
|
|
|
|
204
|
|
|
|
|
205
|
|
|
|
|
206
|
|
|
|
|
207
|
|
P
432
|
|
|
208
|
|
|
|
|
209
|
|
F
432
|
|
|
210
|
|
|
|
|
211
|
|
I
432
|
|
|
212
|
|
|
|
|
213
|
|
|
|
|
214
|
|
|
|
|
215
|
|
|
|
|
216
|
|
|
|
|
217
|
|
|
|
|
218
|
|
|
|
|
219
|
|
|
|
|
220
|
|
|
|
|
221
|
|
|
|
|
222
|
|
|
|
|
223
|
|
|
|
|
224
|
|
|
|
|
225
|
|
|
|
|
226
|
|
|
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227
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228
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229
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230
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†
For the five space groups Aem2 (39), Aea2 (41), Cmce (64), Cmme (67) and Ccce (68), the `new' space-group symbols, containing the symbol ` e' for the `double' glide plane, are given for all settings. These symbols were first introduced in the Fourth Edition of this volume ( IT 1995); cf. Foreword to the Fourth Edition. For further explanations, see Section 1.3.2, Note (x)
and the space-group diagrams.
‡For space groups Cmca (64), Cmma (67) and Imma (74), the first lines of the extended symbols, as tabulated here, correspond with the symbols for the six settings in the diagrams of these space groups (Part 7). An alternative formulation which corresponds with the coordinate triplets is given in Section 4.3.3 .
§Axes and parallel to axes 3 are not indicated in the extended symbols: cf. Chapter 4.1
. For the glide-plane symbol ` e', see the Foreword to the Fourth Edition ( IT 1995 ) and Section 1.3.2, Note (x)
.
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Additional complications arise from the presence of fractional translations due to glide planes in the primitive cell [groups (7), (13), (14)], due to centred cells [ (5), (8), (12)], or due to both [ (9), (15)]. For these groups, three different choices of the two oblique axes are possible which are called `cell choices' 1, 2 and 3 (see Section 2.2.16
). If this is combined with the three choices of the unique axis, symbols result. If we add the effect of the permutation of the two oblique axes (and simultaneously reversing the sense of the unique axis to keep the system right-handed, as in abc and ), we arrive at the symbols listed in Table 4.3.2.1 for each of the eight space groups mentioned above.
The space-group symbols (3), (4), (6), (10) and (11) do not depend on the cell choice: in these cases, one line of six space-group symbols is sufficient.
For space groups with centred lattices (A, B, C, I), extended symbols are given; the `additional symmetry elements' (due to the centring) are printed in the half line below the space-group symbol.
The use of the present tabulation is illustrated by two examples, Pm, which does not depend on the cell choice, and , which does.
Examples
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(1) Pm (6)
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(i) Unique axis b
In the first column, headed by abc, one finds the full symbol P1m1. Interchanging the labels of the oblique axes a and c does not change this symbol, which is found again in the second column headed by .
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(ii) Unique axis c
In the third column, headed by abc, one finds the symbol P11m. Again, this symbol is conserved in the interchange of the oblique axes a and b, as seen in the fourth column headed by .
The same applies to the setting with unique axis a, columns five and six.
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(2)
The short symbol is followed by three lines, corresponding to the cell choices 1, 2, 3. Each line contains six full space-group symbols.
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(i) Unique axis b
The column headed by abc contains the three symbols , and , equivalent to the short symbol and corresponding to the cell choices 1, 2, 3. In the half line below each symbol, the additional symmetry elements are indicated (extended symbol). If the oblique axes a and c are interchanged, the column under cba lists the symbols , and for the three cell choices.
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(ii) Unique axis c
The column under abc contains the symbols , and , corresponding to the cell choices 1, 2 and 3. If the oblique axes a and b are interchanged, the column under applies.
Similar considerations apply to the a-axis setting.
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