Crystal Lab › Prototype structures › Trigonal
Rhombohedral CuTi₂S₄ CuS₄Ti₂
Trigonal · space group R-3m (No. 166) · Pearson hR28
Symmetry elements and Wyckoff positions (interactive)
Rhombohedral CuTi₂S₄ in R-3m
SettingUnit cell
- Lattice constants
- a = 7.024 Å, b = 7.024 Å, c = 34.834 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 1488.4 ų
- Atoms in the conventional cell
- 84 (Ti 24, Cu 12, S 48)
- Formula units Z
- 12
- Pearson symbol
- hR28 — hexagonal / trigonal, rhombohedral lattice, 28 atoms per conventional cell
- Symmetry operations
- 36 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ti7 | Ti | 3a | 3 | 0.0000 | 0.0000 | 0.0000 |
| Ti8 | Ti | 3b | 3 | 0.0000 | 0.0000 | 0.5000 |
| Cu1 | Cu | 6c | 6 | 0.0000 | 0.0000 | 0.1876 |
| Cu2 | Cu | 6c | 6 | 0.0000 | 0.0000 | 0.3545 |
| S3 | S | 6c | 6 | 0.0000 | 0.0000 | 0.1232 |
| S4 | S | 6c | 6 | 0.0000 | 0.0000 | 0.2889 |
| S5 | S | 18h | 18 | 0.8237 | 0.1763 | 0.3757 |
| S6 | S | 18h | 18 | 0.1602 | 0.8398 | 0.4544 |
| Ti9 | Ti | 18h | 18 | 0.5045 | 0.4955 | 0.5810 |
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 84 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
AB4C2_hR28_166_2c_2c2h_abh-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR28, then the space-group number 166, then the Wyckoff letters occupied by each element in turn (Ti: 3a; Ti: 3b; Cu: 6c; Cu: 6c; S: 6c; S: 6c; S: 18h; S: 18h; Ti: 18h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: Rhombohedral.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB4C2_hR28_166_2c_2c2h_abh-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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