Crystal Lab › Prototype structures › Tetragonal
K₃CrO₈
Tetragonal · space group I-42m (No. 121) · Pearson tI24
Symmetry elements and Wyckoff positions (interactive)
K₃CrO₈ in I-42m
SettingUnit cell
- Lattice constants
- a = 6.703 Å, b = 6.703 Å, c = 7.632 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 342.9 ų
- Atoms in the conventional cell
- 24 (Cr 2, K 6, O 16)
- Formula units Z
- 2
- Pearson symbol
- tI24 — tetragonal, body-centred lattice, 24 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Cr1 | Cr | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| K2 | K | 2b | 2 | 0.0000 | 0.0000 | 0.5000 |
| K3 | K | 4d | 4 | 0.0000 | 0.5000 | 0.2500 |
| O4 | O | 8i | 8 | 0.1355 | 0.1355 | 0.1788 |
| O5 | O | 8i | 8 | 0.7079 | 0.7079 | 0.5082 |
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 24 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
AB3C8_tI24_121_a_bd_2i-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI24, then the space-group number 121, then the Wyckoff letters occupied by each element in turn (Cr: 2a; K: 2b; K: 4d; O: 8i; O: 8i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Zr₃GeO₈ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB3C8_tI24_121_a_bd_2i-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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