Crystal Lab › Prototype structures › Trigonal
Cu₂Ta₄O₁₁
Trigonal · space group R-3c (No. 167) · Pearson hR36
Symmetry elements and Wyckoff positions (interactive)
Cu₂Ta₄O₁₁ in R-3c
SettingUnit cell
- Lattice constants
- a = 6.219 Å, b = 6.219 Å, c = 37.107 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 1242.9 ų
- Atoms in the conventional cell
- 108 (Ta 24, O 66, Cu 18)
- Formula units Z
- 6
- Pearson symbol
- hR36 — hexagonal / trigonal, rhombohedral lattice, 36 atoms per conventional cell
- Symmetry operations
- 36 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ta5 | Ta | 6b | 6 | 0.0000 | 0.0000 | 0.0000 |
| O2 | O | 12c | 12 | 0.0000 | 0.0000 | 0.4069 |
| Cu1 | Cu | 18d | 18 | 0.5000 | 0.0000 | 0.0000 |
| O3 | O | 18e | 18 | 0.2457 | 0.0000 | 0.2500 |
| Ta6 | Ta | 18e | 18 | 0.6374 | 0.0000 | 0.2500 |
| O4 | O | 36f | 36 | 0.3703 | 0.9437 | 0.6978 |
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 108 atoms drawn above are these sites multiplied by all 36 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
A3B11C4_hR36_167_d_cef_be-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR36, then the space-group number 167, then the Wyckoff letters occupied by each element in turn (Ta: 6b; O: 12c; Cu: 18d; O: 18e; Ta: 18e; O: 36f). 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 A3B11C4_hR36_167_d_cef_be-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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