Crystal Lab › Prototype structures › Orthorhombic
BaIr₂Ge₇
Orthorhombic · space group Cmmm (No. 65) · Pearson oC96
Symmetry elements and Wyckoff positions (interactive)
BaIr₂Ge₇ in Cmmm
SettingUnit cell
- Lattice constants
- a = 37.656 Å, b = 6.441 Å, c = 6.400 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 1552.3 ų
- Atoms in the conventional cell
- 96 (Ba 8, Ge 72, Ir 16)
- Formula units Z
- 8
- Pearson symbol
- oC96 — orthorhombic, base-centred lattice, 96 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ba1 | Ba | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Ba2 | Ba | 2c | 2 | 0.5000 | 0.0000 | 0.5000 |
| Ba3 | Ba | 4g | 4 | 0.6433 | 0.0000 | 0.0000 |
| Ge4 | Ge | 4g | 4 | 0.5334 | 0.0000 | 0.0000 |
| Ir11 | Ir | 4g | 4 | 0.0982 | 0.0000 | 0.0000 |
| Ir12 | Ir | 4g | 4 | 0.2115 | 0.0000 | 0.0000 |
| Ge5 | Ge | 4h | 4 | 0.0327 | 0.0000 | 0.5000 |
| Ir13 | Ir | 4h | 4 | 0.5979 | 0.0000 | 0.5000 |
| Ir14 | Ir | 4h | 4 | 0.7093 | 0.0000 | 0.5000 |
| Ge6 | Ge | 8o | 8 | 0.1529 | 0.0000 | 0.2161 |
| Ge7 | Ge | 8q | 8 | 0.1525 | 0.2816 | 0.5000 |
| Ge8 | Ge | 16r | 16 | 0.0721 | 0.2492 | 0.2519 |
| Ge9 | Ge | 16r | 16 | 0.2221 | 0.3650 | 0.1420 |
| Ge10 | Ge | 16r | 16 | 0.2212 | 0.1350 | 0.3620 |
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 96 atoms drawn above are these sites multiplied by all 16 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
AB9C2_oC96_65_acg_ghoq3r_2g2h-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC96, then the space-group number 65, then the Wyckoff letters occupied by each element in turn (Ba: 2a; Ba: 2c; Ba: 4g; Ge: 4g; Ir: 4g; Ir: 4g; Ge: 4h; Ir: 4h; Ir: 4h; Ge: 8o; Ge: 8q; Ge: 16r; Ge: 16r; Ge: 16r). 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 AB9C2_oC96_65_acg_ghoq3r_2g2h-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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