Crystal Lab › Prototype structures › Hexagonal
Hexagonal Ba₃CoIr₂O₉
Hexagonal · space group P63/mmc (No. 194) · Pearson hP30
Symmetry elements and Wyckoff positions (interactive)
Hexagonal Ba₃CoIr₂O₉ in P63/mmc
SettingUnit cell
- Lattice constants
- a = 5.764 Å, b = 5.764 Å, c = 14.295 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 411.3 ų
- Atoms in the conventional cell
- 30 (Co 2, Ba 6, Ir 4, O 18)
- Formula units Z
- 2
- Pearson symbol
- hP30 — hexagonal / trigonal, primitive lattice, 30 atoms per conventional cell
- Symmetry operations
- 24 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Co3 | Co | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Ba1 | Ba | 2b | 2 | 0.0000 | 0.0000 | 0.2500 |
| Ba2 | Ba | 4f | 4 | 0.3333 | 0.6667 | 0.9120 |
| Ir4 | Ir | 4f | 4 | 0.3333 | 0.6667 | 0.1540 |
| O5 | O | 6h | 6 | 0.5004 | 0.0008 | 0.2500 |
| O6 | O | 12k | 12 | 0.1619 | 0.3238 | 0.4196 |
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 30 atoms drawn above are these sites multiplied by all 24 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
A3BC2D9_hP30_194_bf_a_f_hk-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP30, then the space-group number 194, then the Wyckoff letters occupied by each element in turn (Co: 2a; Ba: 2b; Ba: 4f; Ir: 4f; O: 6h; O: 12k). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ba₃CoSb₂O₉, Ba₃NiIr₂O₉, Ba₃(W_{0.5}Fe_{0.5})₂FeO₉ <!--beginning with an
Note: Hexagonal.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3BC2D9_hP30_194_bf_a_f_hk-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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