Crystal Lab › Prototype structures › Orthorhombic
Cs₂Se
Orthorhombic · space group Fdd2 (No. 43) · Pearson oF24
Symmetry elements and Wyckoff positions (interactive)
Cs₂Se in Fdd2
SettingUnit cell
- Lattice constants
- a = 16.490 Å, b = 11.750 Å, c = 6.775 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 1312.7 ų
- Atoms in the conventional cell
- 24 (Se 8, Cs 16)
- Formula units Z
- 8
- Pearson symbol
- oF24 — orthorhombic, face-centred lattice, 24 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Se2 | Se | 8a | 8 | 0.0000 | 0.0000 | 0.7500 |
| Cs1 | Cs | 16b | 16 | 0.9520 | 0.6751 | 0.8118 |
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
A2B_oF24_43_b_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oF24, then the space-group number 43, then the Wyckoff letters occupied by each element in turn (Se: 8a; Cs: 16b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B_oF24_43_b_a-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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