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Crystal Lab › Prototype structures › Orthorhombic

CuBiSeCl₂

Orthorhombic · space group Pnma (No. 62) · Pearson oP20

Symmetry elements and Wyckoff positions (interactive)

CuBiSeCl₂ in Pnma

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

Unit cell

Lattice constants
a = 8.784 Å, b = 3.998 Å, c = 13.140 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
461.5 ų
Atoms in the conventional cell
20 (Bi 4, Cl 8, Cu 4, Se 4)
Formula units Z
4
Pearson symbol
oP20 — orthorhombic, primitive lattice, 20 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Bi1Bi4c40.27150.25000.9478
Cl2Cl4c40.43400.25000.5955
Cl3Cl4c40.55940.25000.8984
Cu4Cu4c40.54030.25000.3004
Se5Se4c40.76060.25000.1943

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 20 atoms drawn above are these sites multiplied by all 8 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

AB2CD_oP20_62_c_2c_c_c-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP20, then the space-group number 62, then the Wyckoff letters occupied by each element in turn (Bi: 4c; Cl: 4c; Cl: 4c; Cu: 4c; Se: 4c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2CD_oP20_62_c_2c_c_c-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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