International
Tables for
Crystallography
Volume B
Reciprocal space
Edited by U. Shmueli

International Tables for Crystallography (2006). Vol. B. ch. 1.5, p. 172   | 1 | 2 |

Table 1.5.5.3 

M. I. Aroyoa* and H. Wondratschekb

a Faculty of Physics, University of Sofia, bulv. J. Boucher 5, 1164 Sofia, Bulgaria , and bInstitut für Kristallographie, Universität, D-76128 Karlsruhe, Germany
Correspondence e-mail:  aroyo@phys.uni-sofia.bg

Table 1.5.5.3 | top | pdf |
The k-vector types for the space groups [I4/mmm], [I4/mcm], [I4_{1}/amd] and [I4_{1}/acd]

Comparison of the k-vector labels and parameters of CDML with the Wyckoff positions of IT A for [I4/mmm] [(D_{4h}^{17})], isomorphic to the reciprocal-space group [{\cal G}^*] of [4/mmmI]. For the asymmetric unit, see Fig. 1.5.5.3[link]. Two ratios of the lattice constants are distinguished for the representation domains of CDML: [a \gt c] and [a \lt c], see Figs. 1.5.5.3[link](a, b) and (c, d). The sign ∼ means symmetrically equivalent. The parameter ranges for the planes and the general position GP refer to the asymmetric unit. The coordinates x, y, z of IT A are related to the k-vector coefficients of CDML by [x = 1/2(-k_{1} + k_{2})], [y = 1/2(k_{1} + k_{2} + 2k_{3})], [z = 1/2(k_{1}+ k_{2})].

k -vector labels, CDML Wyckoff position, IT A Parameters (see Fig. 1.5.5.3)[link], IT A
[a \gt c] [a \lt c] [a \gt c] [a \lt c]
Γ 0, 0, 0 Γ 0, 0, 0 [2\,\,a\,\,4/mmm] 0, 0, 0
[M\,\,- {1 \over 2}, {1 \over 2}, {1 \over 2}] [M\,\,{1 \over 2}, {1 \over 2}, - {1 \over 2}] [2\,\,b\,\,4/mmm] [{1 \over 2}, {1 \over 2},0] [0,0,{1 \over 2}]
[X\,\,0,0,{1 \over 2}] [X\,\,0,0,{1 \over 2}] 4 c mmm. [0,{1 \over 2},0]
[P\,\,{1 \over 4}, {1 \over 4}, {1 \over 4}] [P\,\,{1 \over 4}, {1 \over 4}, {1 \over 4}] [4\,\,d\,\,\bar{4}m2] [0,{1 \over 2}, {1 \over 4}]
[N\,\,0,{1 \over 2},0] [N\,\,0,{1 \over 2},0] [8\,\,f\,\,..2/m] [{1 \over 4}, {1 \over 4}, {1 \over 4}]
Λ α, α, −α Λ α, α, −α 4 e 4mm [0,0,z\hbox{:}\,\,0 \lt z \leq z_{0}] [0 \lt z \lt {1 \over 2}]
[V\,\,- {1 \over 2} + \alpha, {1 \over 2} + \alpha, {1 \over 2} - \alpha] 4 e 4mm [{1 \over 2}, {1 \over 2}, z\!: 0 \lt z \lt z_{1} = {1 \over 2} - z_{0}]
[W\,\,\alpha, \alpha, {1 \over 2} - \alpha] [W\,\,\alpha, \alpha, {1 \over 2} - \alpha] 8 g 2mm. [0, {1 \over 2},z\hbox{:}\,\,0 \lt z \lt {1 \over 4}]
Σα, α, α Σα, α, α 8 h m.2m [x, x, 0\!: 0 \lt x \lt {1 \over 2}] [0 \lt x \leq s_{1}]
[F\,\,{1 \over 2} - \alpha, {1 \over 2} + \alpha, - {1 \over 2} + \alpha] 8 h m.2m [x,x,{1 \over 2}\hbox{:}\,\, 0 \lt x \lt s = {1 \over 2} - s_{1}]
Δ 0, 0, α Δ 0, 0, α 8 i m2m. [0,y,0\hbox{:}\,\,0 \lt y \lt {1 \over 2}]
[Y\,\,- \alpha, \alpha, {1 \over 2}] [Y\,\,- \alpha, \alpha, {1 \over 2}] 8 j m2m. [x, {1 \over 2}, 0\!\!: 0 \lt x \lt {1 \over 2}] [0 \lt x \leq r]
[U\,\,{1 \over 2}, {1 \over 2}, - {1 \over 2} + \alpha] 8 j m2m. [0,y,{1 \over 2}\hbox{:}\,\, 0 \lt y \lt g = {1 \over 2} - r]
[Q\,\,{1 \over 4} - \alpha, {1 \over 4} + \alpha, {1 \over 4} - \alpha] [Q\,\,{1 \over 4} - \alpha, {1 \over 4} + \alpha, {1 \over 4} - \alpha] 16 k ..2 [x, {1 \over 2} - x, {1 \over 4}\!\!: 0 \lt x \lt {1 \over 4}]
C α, α, β C α, α, β 16 l m.. [x,y,0\hbox{:}\,\,0 \lt x \lt y \lt {1 \over 2}] §
[D\,\,{1 \over 2} - \alpha, {1 \over 2} + \alpha, - {1 \over 2} + \beta] 16 l m.. [x,y,{1 \over 2}]
B α, β, −α B α, β, −α 16 m ..m [x,x,z\hbox{:}\,\,0 \lt x \lt {1 \over 2},0 \lt z \lt {1 \over 4} \cup 0 \lt x \lt {1 \over 4},z = {1 \over 4}]
A α, α, β A α, α, β 16 n .m. [0,y,z\hbox{:}\,\,0 \lt y \lt {1 \over 2},0 \lt z \lt {1 \over 2}]
[E\,\,\alpha - \beta, \alpha + \beta, {1 \over 2} - \alpha] [E\,\,\alpha - \beta, \alpha + \beta, {1 \over 2} - \alpha] 16 n .m. [x, {1 \over 2},z]: transferred to [A = 0, y, z]
GP α, β, γ GP α, β, γ 32 o 1 [x,y,z\hbox{:}\,\,0 \lt x \lt y \lt {1 \over 2},0 \lt z \lt {1 \over 4} \cup 0 \lt x \lt y \lt {1 \over 2} - x,z = {1 \over 4}]
If the parameter range is different from that for [a \gt c].
[z_{0}] is a coordinate of point [Z_{0}] etc., see Figs. 1.5.5.3[link](b), (d).
§For [a \lt c], the parameter range includes the equivalent of [D = MSG].
The parameter range includes A and the equivalent of E.