Crystal Lab › Prototype structures › Orthorhombic
CuBiSeCl₂
Orthorhombic · space group Pnma (No. 62) · Pearson oP20
Symmetry elements and Wyckoff positions (interactive)
CuBiSeCl₂ in Pnma
SettingUnit 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
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Bi1 | Bi | 4c | 4 | 0.2715 | 0.2500 | 0.9478 |
| Cl2 | Cl | 4c | 4 | 0.4340 | 0.2500 | 0.5955 |
| Cl3 | Cl | 4c | 4 | 0.5594 | 0.2500 | 0.8984 |
| Cu4 | Cu | 4c | 4 | 0.5403 | 0.2500 | 0.3004 |
| Se5 | Se | 4c | 4 | 0.7606 | 0.2500 | 0.1943 |
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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