Crystal Lab › Prototype structures › Tetragonal
Sr₂NiWO₆
Tetragonal · space group I4/m (No. 87) · Pearson tI20
Symmetry elements and Wyckoff positions (interactive)
Sr₂NiWO₆ in I4/m
SettingUnit cell
- Lattice constants
- a = 5.557 Å, b = 5.557 Å, c = 7.913 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 244.4 ų
- Atoms in the conventional cell
- 20 (Ni 2, W 2, Sr 4, O 12)
- Formula units Z
- 2
- Pearson symbol
- tI20 — tetragonal, body-centred lattice, 20 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ni1 | Ni | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| W5 | W | 2b | 2 | 0.0000 | 0.0000 | 0.5000 |
| Sr4 | Sr | 4d | 4 | 0.0000 | 0.5000 | 0.2500 |
| O2 | O | 4e | 4 | 0.0000 | 0.0000 | 0.2550 |
| O3 | O | 8h | 8 | 0.2890 | 0.2270 | 0.0000 |
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 20 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
AB6C2D_tI20_87_a_eh_d_b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI20, then the space-group number 87, then the Wyckoff letters occupied by each element in turn (Ni: 2a; W: 2b; Sr: 4d; O: 4e; O: 8h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Sr₂MgWO₆ <!--beginning with an
Note: Double Perovskite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB6C2D_tI20_87_a_eh_d_b-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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