Crystal Lab › Prototype structures › Tetragonal
Sm₂NiGa₁₂
Tetragonal · space group P4/nbm (No. 125) · Pearson tP30
Symmetry elements and Wyckoff positions (interactive)
Sm₂NiGa₁₂ in P4/nbm
SettingUnit cell
- Lattice constants
- a = 5.995 Å, b = 5.995 Å, c = 15.401 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 553.6 ų
- Atoms in the conventional cell
- 30 (Ni 2, Ga 24, Sm 4)
- Formula units Z
- 2
- Pearson symbol
- tP30 — tetragonal, primitive lattice, 30 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ni5 | Ni | 2c | 2 | 0.7500 | 0.2500 | 0.0000 |
| Ga1 | Ga | 4g | 4 | 0.2500 | 0.2500 | 0.1811 |
| Ga2 | Ga | 4g | 4 | 0.2500 | 0.2500 | 0.3394 |
| Sm6 | Sm | 4h | 4 | 0.7500 | 0.2500 | 0.2450 |
| Ga3 | Ga | 8m | 8 | 0.5704 | 0.4296 | 0.0833 |
| Ga4 | Ga | 8m | 8 | 0.5720 | 0.4280 | 0.5721 |
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 30 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
A12BC2_tP30_125_2g2m_c_h-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP30, then the space-group number 125, then the Wyckoff letters occupied by each element in turn (Ni: 2c; Ga: 4g; Ga: 4g; Sm: 4h; Ga: 8m; Ga: 8m). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ce₂CuGa₁₂, Ce₂IrGa₁₂, Ce₂NiGa₁₂, Ce₂PdGa₁₂, La₂CuGa₁₂, La₂NiGa₁₂, La₂PdGa₁₂, Nd₂CuGa₁₂, Nd₂NiGa₁₂, Nd₂PdGa₁₂, Pr₂CuGa₁₂, Pr₂NiGa₁₂, Pr₂PdGa₁₂, Sm₂CuGa₁₂, Sm₂PdGa₁₂ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A12BC2_tP30_125_2g2m_c_h-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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