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Crystal Lab › Prototype structures › Monoclinic

α-CuCrP₂S₆ CrCuP₂S₆

Monoclinic · space group P1c1 (No. 7) · Pearson mP40

Symmetry elements and Wyckoff positions (interactive)

α-CuCrP₂S₆ in P1c1

Setting
Loading the group…
x = 0.10, y = 0.17, z = 0.08

Unit cell

Lattice constants
a = 5.935 Å, b = 10.282 Å, c = 13.368 Å; α = 90.00°, β = 106.78°, γ = 90.00°
Cell volume
781.0 ų
Atoms in the conventional cell
40 (Cr 4, Cu 4, P 8, S 24)
Formula units Z
4
Pearson symbol
mP40 — monoclinic, primitive lattice, 40 atoms per conventional cell
Symmetry operations
2 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Cr1Cr2a20.07100.00000.3550
Cr2Cr2a20.44100.49600.1480
Cr3Cu2a20.00000.33200.2500
Cr4Cu2a20.52700.83000.2460
P5P2a20.07900.33700.8270
P6P2a20.54500.83800.8170
P7P2a20.95400.66800.1540
P8P2a20.45700.83700.6450
S9S2a20.72500.99600.3710
S10S2a20.24700.49100.3680
S11S2a20.29000.01100.6250
S12S2a20.80200.49100.1180
S13S2a20.28800.17600.8670
S14S2a20.75700.68200.8690
S15S2a20.73900.82600.1150
S16S2a20.23000.68400.6260
S17S2a20.26100.18300.3720
S18S2a20.76800.66800.3620
S19S2a20.78600.83200.6270
S20S2a20.26300.68800.1190

The multiplicity and the Wyckoff letter say how many copies of the site the group makes in one cell and on which kind of symmetry element the site sits; the 40 atoms drawn above are these sites multiplied by all 2 operations. Press Wyckoff under Colour to see the sites, and tick a symmetry element on the left to see which atoms lie on it.

How to read the label

ABC2D6_mP40_7_2a_2a_4a_12a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol mP40, then the space-group number 7, then the Wyckoff letters occupied by each element in turn (Cr: 2a; Cr: 2a; Cu: 2a; Cu: 2a; P: 2a; P: 2a; P: 2a; P: 2a; S: 2a; S: 2a; S: 2a; S: 2a; S: 2a; S: 2a; S: 2a; S: 2a; S: 2a; S: 2a; S: 2a; S: 2a). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: \beta-CuCrP₂S₆.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry ABC2D6_mP40_7_2a_2a_4a_12a-001 (M. J. Mehl et al., Comput. Mater. Sci. 136, S1 (2017); D. Hicks et al., ibid. 161, S1 (2019) and 199, 110450 (2021); S. Eckert et al., ibid. 240, 112988 (2024)). Symmetry elements, Wyckoff assignment and the diagram are computed on this page from the group operations.

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