Crystal Lab › Prototype structures › Hexagonal
ε-GaSe
Hexagonal · space group P-6m2 (No. 187) · Pearson hP8
Symmetry elements and Wyckoff positions (interactive)
ε-GaSe in P-6m2
SettingUnit cell
- Lattice constants
- a = 3.735 Å, b = 3.735 Å, c = 15.887 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 191.9 ų
- Atoms in the conventional cell
- 8 (Ga 4, Se 4)
- Formula units Z
- 4
- Pearson symbol
- hP8 — hexagonal / trigonal, primitive lattice, 8 atoms per conventional cell
- Symmetry operations
- 12 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ga1 | Ga | 2g | 2 | 0.0000 | 0.0000 | 0.0750 |
| Se3 | Se | 2g | 2 | 0.0000 | 0.0000 | 0.6500 |
| Ga2 | Ga | 2h | 2 | 0.3333 | 0.6667 | 0.5700 |
| Se4 | Se | 2h | 2 | 0.3333 | 0.6667 | 0.1500 |
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 8 atoms drawn above are these sites multiplied by all 12 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_hP8_187_gh_gh-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP8, then the space-group number 187, then the Wyckoff letters occupied by each element in turn (Ga: 2g; Se: 2g; Ga: 2h; Se: 2h). 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: \epsilon-GaSe.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_hP8_187_gh_gh-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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