Crystal Lab › Prototype structures › Hexagonal
Ca₅Ir₃O₁₂
Hexagonal · space group P-62m (No. 189) · Pearson hP20
Symmetry elements and Wyckoff positions (interactive)
Ca₅Ir₃O₁₂ in P-62m
SettingUnit cell
- Lattice constants
- a = 9.347 Å, b = 9.347 Å, c = 3.171 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 239.9 ų
- Atoms in the conventional cell
- 20 (Ca 5, Ir 3, O 12)
- Formula units Z
- 1
- Pearson symbol
- hP20 — hexagonal / trigonal, primitive lattice, 20 atoms per conventional cell
- Symmetry operations
- 12 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ca1 | Ca | 2d | 2 | 0.3333 | 0.6667 | 0.5000 |
| Ir3 | Ir | 3f | 3 | 0.3330 | 0.0000 | 0.0000 |
| Ca2 | Ca | 3g | 3 | 0.7127 | 0.0000 | 0.5000 |
| O4 | O | 3g | 3 | 0.2006 | 0.0000 | 0.5000 |
| O5 | O | 3g | 3 | 0.4617 | 0.0000 | 0.5000 |
| O6 | O | 6j | 6 | 0.4460 | 0.2407 | 0.0000 |
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 20 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
A5B3C12_hP20_189_dg_f_2gj-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP20, then the space-group number 189, then the Wyckoff letters occupied by each element in turn (Ca: 2d; Ir: 3f; Ca: 3g; O: 3g; O: 3g; O: 6j). 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 A5B3C12_hP20_189_dg_f_2gj-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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