Crystal Lab › Prototype structures › Orthorhombic
Na₂Tl
Orthorhombic · space group C2221 (No. 20) · Pearson oC48
Symmetry elements and Wyckoff positions (interactive)
Na₂Tl in C2221
SettingUnit cell
- Lattice constants
- a = 8.880 Å, b = 13.935 Å, c = 11.693 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 1446.8 ų
- Atoms in the conventional cell
- 48 (Na 32, Tl 16)
- Formula units Z
- 16
- Pearson symbol
- oC48 — orthorhombic, base-centred lattice, 48 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Na2 | Na | 4a | 4 | 0.4080 | 0.0000 | 0.0000 |
| Na1 | Na | 4b | 4 | 0.0000 | 0.9330 | 0.2500 |
| Na3 | Na | 8c | 8 | 0.6940 | 0.2030 | 0.6710 |
| Na4 | Na | 8c | 8 | 0.2780 | 0.8740 | 0.4570 |
| Na5 | Na | 8c | 8 | 0.4050 | 0.6300 | 0.4160 |
| Tl6 | Tl | 8c | 8 | 0.5484 | 0.2155 | 0.3820 |
| Tl7 | Tl | 8c | 8 | 0.6776 | 0.9502 | 0.7770 |
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 48 atoms drawn above are these sites multiplied by all 8 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_oC48_20_ab3c_2c-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC48, then the space-group number 20, then the Wyckoff letters occupied by each element in turn (Na: 4a; Na: 4b; Na: 8c; Na: 8c; Na: 8c; Tl: 8c; Tl: 8c). 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_oC48_20_ab3c_2c-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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