Crystal Lab › Prototype structures › Trigonal
γ-GaSe
Trigonal · space group R3m (No. 160) · Pearson hR4
Symmetry elements and Wyckoff positions (interactive)
γ-GaSe in R3m
SettingUnit cell
- Lattice constants
- a = 3.739 Å, b = 3.739 Å, c = 23.862 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 288.9 ų
- Atoms in the conventional cell
- 12 (Ga 6, Se 6)
- Formula units Z
- 6
- Pearson symbol
- hR4 — hexagonal / trigonal, rhombohedral lattice, 4 atoms per conventional cell
- Symmetry operations
- 18 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ga1 | Ga | 3a | 3 | 0.0000 | 0.0000 | 0.9500 |
| Ga2 | Ga | 3a | 3 | 0.0000 | 0.0000 | 0.0500 |
| Se3 | Se | 3a | 3 | 0.0000 | 0.0000 | 0.5667 |
| Se4 | Se | 3a | 3 | 0.0000 | 0.0000 | 0.7667 |
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 12 atoms drawn above are these sites multiplied by all 18 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
AB_hR4_160_2a_2a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR4, then the space-group number 160, then the Wyckoff letters occupied by each element in turn (Ga: 3a; Ga: 3a; Se: 3a; Se: 3a). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
InSe <!--beginning with an
Note: \gamma-GaSe.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_hR4_160_2a_2a-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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