Crystal Lab › Prototype structures › Orthorhombic
GeAs₂
Orthorhombic · space group Pbam (No. 55) · Pearson oP24
Symmetry elements and Wyckoff positions (interactive)
GeAs₂ in Pbam
SettingUnit cell
- Lattice constants
- a = 14.760 Å, b = 10.160 Å, c = 3.728 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 559.1 ų
- Atoms in the conventional cell
- 24 (As 16, Ge 8)
- Formula units Z
- 8
- Pearson symbol
- oP24 — orthorhombic, primitive lattice, 24 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| As1 | As | 4g | 4 | 0.2958 | 0.3537 | 0.0000 |
| As2 | As | 4g | 4 | 0.0385 | 0.2262 | 0.0000 |
| Ge5 | Ge | 4g | 4 | 0.1381 | 0.4188 | 0.0000 |
| As3 | As | 4h | 4 | 0.1117 | 0.1011 | 0.5000 |
| As4 | As | 4h | 4 | 0.4028 | 0.0631 | 0.5000 |
| Ge6 | Ge | 4h | 4 | 0.2664 | 0.2015 | 0.5000 |
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 24 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
A2B_oP24_55_2g2h_gh-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP24, then the space-group number 55, then the Wyckoff letters occupied by each element in turn (As: 4g; As: 4g; Ge: 4g; As: 4h; As: 4h; Ge: 4h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
SiAs₂, SiP₂ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B_oP24_55_2g2h_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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