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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

Setting
Loading the group…
x = 0.10, y = 0.17, z = 0.08

Unit 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

SiteElementWyckoffMultiplicityxyz
Ni1Ni2a20.00000.00000.0000
W5W2b20.00000.00000.5000
Sr4Sr4d40.00000.50000.2500
O2O4e40.00000.00000.2550
O3O8h80.28900.22700.0000

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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