Crystal Lab › Prototype structures › Trigonal
High Temperature K₂LiAlF₆ AlF₆K₂Li
Trigonal · space group R-3m (No. 166) · Pearson hR20
Symmetry elements and Wyckoff positions (interactive)
High Temperature K₂LiAlF₆ in R-3m
SettingUnit cell
- Lattice constants
- a = 5.620 Å, b = 5.620 Å, c = 27.620 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 755.5 ų
- Atoms in the conventional cell
- 60 (Al 6, K 12, Li 6, F 36)
- Formula units Z
- 6
- Pearson symbol
- hR20 — hexagonal / trigonal, rhombohedral lattice, 20 atoms per conventional cell
- Symmetry operations
- 36 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Al1 | Al | 3a | 3 | 0.0000 | 0.0000 | 0.0000 |
| Al2 | Al | 3b | 3 | 0.0000 | 0.0000 | 0.5000 |
| K5 | K | 6c | 6 | 0.0000 | 0.0000 | 0.1278 |
| K6 | K | 6c | 6 | 0.0000 | 0.0000 | 0.2803 |
| Li7 | Li | 6c | 6 | 0.0000 | 0.0000 | 0.4033 |
| F3 | F | 18h | 18 | 0.4807 | 0.5193 | 0.1275 |
| F4 | F | 18h | 18 | 0.5143 | 0.4857 | 0.2956 |
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 60 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
AB6C2D_hR20_166_ab_2h_2c_c-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR20, then the space-group number 166, then the Wyckoff letters occupied by each element in turn (Al: 3a; Al: 3b; K: 6c; K: 6c; Li: 6c; F: 18h; F: 18h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ba₂MnTeO₆, Cs₂NaCrF₆ <!--beginning with an
Note: HT.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB6C2D_hR20_166_ab_2h_2c_c-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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