Crystal Lab › Prototype structures › Cubic
High Temperature Cu₂Se
Cubic · space group Fm-3m (No. 225) · Pearson cF76
Symmetry elements and Wyckoff positions (interactive)
High Temperature Cu₂Se in Fm-3m
SettingUnit cell
- Lattice constants
- a = 5.859 Å, b = 5.859 Å, c = 5.859 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 201.1 ų
- Atoms in the conventional cell
- 76 (Se 4, Cu 72)
- Formula units Z
- 4
- Pearson symbol
- cF76 — cubic, face-centred lattice, 76 atoms per conventional cell
- Symmetry operations
- 192 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Se4 | Se | 4a | 4 | 0.0000 | 0.0000 | 0.0000 |
| Cu1 | Cu | 8c | 8 | 0.2500 | 0.2500 | 0.2500 |
| Cu2 | Cu | 32f | 32 | 0.3090 | 0.3090 | 0.3090 |
| Cu3 | Cu | 32f | 32 | 0.3840 | 0.3840 | 0.3840 |
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 76 atoms drawn above are these sites multiplied by all 192 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
A18B_cF76_225_c2f_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol cF76, then the space-group number 225, then the Wyckoff letters occupied by each element in turn (Se: 4a; Cu: 8c; Cu: 32f; Cu: 32f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ag₂Te (HT), Cu_{1.8}S <!--beginning with an
Note: HT.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A18B_cF76_225_c2f_a-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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