Crystal Lab › Prototype structures › Tetragonal
AuCsCl₃ (K7₆)
Tetragonal · space group I4/mmm (No. 139) · Pearson tI20 · Strukturbericht K76
Symmetry elements and Wyckoff positions (interactive)
AuCsCl₃ (K7₆) in I4/mmm
SettingUnit cell
- Lattice constants
- a = 7.490 Å, b = 7.490 Å, c = 10.870 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 609.8 ų
- Atoms in the conventional cell
- 20 (Au 4, Cs 4, Cl 12)
- Formula units Z
- 4
- Pearson symbol
- tI20 — tetragonal, body-centred lattice, 20 atoms per conventional cell
- Symmetry operations
- 32 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Au1 | Au | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Au2 | Au | 2b | 2 | 0.0000 | 0.0000 | 0.5000 |
| Cs5 | Cs | 4d | 4 | 0.0000 | 0.5000 | 0.2500 |
| Cl3 | Cl | 4e | 4 | 0.0000 | 0.0000 | 0.2880 |
| Cl4 | Cl | 8h | 8 | 0.2280 | 0.2280 | 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 20 atoms drawn above are these sites multiplied by all 32 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
AB3C_tI20_139_ab_eh_d-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI20, then the space-group number 139, then the Wyckoff letters occupied by each element in turn (Au: 2a; Au: 2b; Cs: 4d; Cl: 4e; Cl: 8h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
AgAuCs₂Cl₆ <!--beginning with an
Note: K7₆.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB3C_tI20_139_ab_eh_d-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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