Crystal Lab › Prototype structures › Trigonal
IrGe₄
Trigonal · space group P31 (No. 144) · Pearson hP15
Symmetry elements and Wyckoff positions (interactive)
IrGe₄ in P31
SettingUnit cell
- Lattice constants
- a = 6.215 Å, b = 6.215 Å, c = 7.784 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 260.4 ų
- Atoms in the conventional cell
- 15 (Ge 12, Ir 3)
- Formula units Z
- 3
- Pearson symbol
- hP15 — hexagonal / trigonal, primitive lattice, 15 atoms per conventional cell
- Symmetry operations
- 3 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ge1 | Ge | 3a | 3 | 0.4904 | 0.2194 | 0.2268 |
| Ge2 | Ge | 3a | 3 | 0.2226 | 0.4873 | 0.1142 |
| Ge3 | Ge | 3a | 3 | 0.0775 | 0.0012 | 0.0000 |
| Ge4 | Ge | 3a | 3 | 0.6097 | 0.0014 | 0.0018 |
| Ir5 | Ir | 3a | 3 | 0.3178 | 0.0008 | 0.5062 |
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 15 atoms drawn above are these sites multiplied by all 3 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
A4B_hP15_144_4a_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP15, then the space-group number 144, then the Wyckoff letters occupied by each element in turn (Ge: 3a; Ge: 3a; Ge: 3a; Ge: 3a; Ir: 3a). 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 A4B_hP15_144_4a_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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