Crystal Lab › Prototype structures › Orthorhombic
TiAl₂Br₈
Orthorhombic · space group Pnn2 (No. 34) · Pearson oP22
Symmetry elements and Wyckoff positions (interactive)
TiAl₂Br₈ in Pnn2
SettingUnit cell
- Lattice constants
- a = 6.274 Å, b = 12.801 Å, c = 8.676 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 696.8 ų
- Atoms in the conventional cell
- 22 (Ti 2, Al 4, Br 16)
- Formula units Z
- 2
- Pearson symbol
- oP22 — orthorhombic, primitive lattice, 22 atoms per conventional cell
- Symmetry operations
- 4 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ti6 | Ti | 2a | 2 | 0.0000 | 0.0000 | 0.5000 |
| Al1 | Al | 4c | 4 | 0.6050 | 0.8135 | 0.4990 |
| Br2 | Br | 4c | 4 | 0.7349 | 0.6796 | 0.0090 |
| Br3 | Br | 4c | 4 | 0.7430 | 0.9075 | 0.3064 |
| Br4 | Br | 4c | 4 | 0.2388 | 0.5935 | 0.2196 |
| Br5 | Br | 4c | 4 | 0.7131 | 0.6459 | 0.5130 |
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 22 atoms drawn above are these sites multiplied by all 4 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
A2B8C_oP22_34_c_4c_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP22, then the space-group number 34, then the Wyckoff letters occupied by each element in turn (Ti: 2a; Al: 4c; Br: 4c; Br: 4c; Br: 4c; Br: 4c). 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 A2B8C_oP22_34_c_4c_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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