P63/mmc (194) space group

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P6₃/mmc (194) space group

Table 3026a. P6₃/mmc (194) space group.

Name in the International Tables for Crystallography	P6₃/mmc	Lattice type	P
Patterson space group	191	Point group	6/mmm
Crystal system	Hexagonal (HCP)	Laue class	6/mmm
Number of symmetry operators	24	d-spacing ratios of allowed Bragg reflections	1, √(4/3), √(4/R2), √(4/3+1/R2), √(4/3+4/R2), √4, ... (R=1.6)
Asymm	0≤ x ≤ 2/3 and 0 ≤ y ≤ 2/3 and 0 ≤ z ≤ 1/4 and x ≤ 2 y and y ≤ min(1-x,2 x)
Symmetry (atomic coordinates)	X, Y, Z; -Y, X-Y, Z; Y-X, -X, Z; -X, -Y, 1/2+Z; Y, Y-X, 1/2+Z; X-Y, X, 1/2+Z; Y, X, -Z; X-Y, -Y, -Z; -X, Y-X, -Z; -Y, -X, 1/2-Z; Y-X, Y, 1/2-Z; X, X-Y, 1/2-Z; -X, -Y, -Z; Y, Y-X, -Z; X-Y, X, -Z; X, Y, 1/2-Z; Y-X, -X, 1/2-Z; -Y, X-Y, 1/2-Z; -Y, -X, Z; Y-X, Y, Z; X, X-Y, Z; Y, X, 1/2+Z; X-Y, -Y, 1/2+Z; -X, Y-X, 1/2+Z.
Conditions for kinematically-allowed reflections	0001:1 = 2n; hkil: none; hh2hl: 1 = 2n; hh01: none
Crystal examples	MgZn₂: 2 Zn at 0, 0, 0 and 0, 0, 1/2; 4 Mg at 1/3, 2/3, z; 2/3, 1/3, z + 1/2; 2/3, 1/3, -z and 1/3, 2/3, -z + 1/2; 6 Zn at x, 2x, 1/4; -2x, -x, 1/4; x, -x, 1/4 and -x, -2x, 3/4. MoS₂,

Table 3026b. Lattice constants of typical structures with P6₃/mmc (194).

63 screw axis

Figure 3026. 6₃ screw axis.