Crystal Lab › Prototype structures › Orthorhombic
ThNi
Orthorhombic · space group Pnma (No. 62) · Pearson oP16
Symmetry elements and Wyckoff positions (interactive)
ThNi in Pnma
SettingUnit cell
- Lattice constants
- a = 14.146 Å, b = 4.286 Å, c = 5.702 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 345.7 ų
- Atoms in the conventional cell
- 16 (Ni 8, Th 8)
- Formula units Z
- 8
- Pearson symbol
- oP16 — orthorhombic, primitive lattice, 16 atoms per conventional cell
- Symmetry operations
- 8 per cell
- Calculated density
- 11.17 g cm⁻³ (cell contents ÷ cell volume, standard atomic weights)
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ni1 | Ni | 4c | 4 | 0.3543 | 0.2500 | 0.0310 |
| Ni2 | Ni | 4c | 4 | 0.1050 | 0.2500 | 0.2560 |
| Th3 | Th | 4c | 4 | 0.2847 | 0.2500 | 0.5366 |
| Th4 | Th | 4c | 4 | 0.0344 | 0.2500 | 0.7479 |
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 16 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
AB_oP16_62_2c_2c-002: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP16, then the space-group number 62, then the Wyckoff letters occupied by each element in turn (Ni: 4c; Ni: 4c; Th: 4c; Th: 4c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
AgSr
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_oP16_62_2c_2c-002 (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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