Crystal Lab › Prototype structures › Tetragonal
RbAlF₄ II AlF₄Rb
Tetragonal · space group P4/mbm (No. 127) · Pearson tP12
Symmetry elements and Wyckoff positions (interactive)
RbAlF₄ II in P4/mbm
SettingUnit cell
- Lattice constants
- a = 5.123 Å, b = 5.123 Å, c = 6.282 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 164.8 ų
- Atoms in the conventional cell
- 12 (Al 2, Rb 2, F 8)
- Formula units Z
- 2
- Pearson symbol
- tP12 — tetragonal, primitive lattice, 12 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Al1 | Al | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Rb4 | Rb | 2c | 2 | 0.0000 | 0.5000 | 0.5000 |
| F2 | F | 4e | 4 | 0.0000 | 0.0000 | 0.2224 |
| F3 | F | 4g | 4 | 0.2159 | 0.7159 | 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 12 atoms drawn above are these sites multiplied by all 16 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
AB4C_tP12_127_a_eg_c-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP12, then the space-group number 127, then the Wyckoff letters occupied by each element in turn (Al: 2a; Rb: 2c; F: 4e; F: 4g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: RbAlF₄ II.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB4C_tP12_127_a_eg_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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