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Crystal Lab › Prototype structures › Orthorhombic

Sr₂Bi₃

Orthorhombic · space group Pnna (No. 52) · Pearson oP20

Symmetry elements and Wyckoff positions (interactive)

Sr₂Bi₃ in Pnna

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

Unit cell

Lattice constants
a = 15.583 Å, b = 6.772 Å, c = 6.639 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
700.7 ų
Atoms in the conventional cell
20 (Sr 8, Bi 12)
Formula units Z
4
Pearson symbol
oP20 — orthorhombic, primitive lattice, 20 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Sr3Sr4c40.25000.00000.4430
Bi1Bi4d40.42940.25000.2500
Sr4Sr4d40.00010.25000.2500
Bi2Bi8e80.65390.06400.0788

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 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

A3B2_oP20_52_de_cd-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP20, then the space-group number 52, then the Wyckoff letters occupied by each element in turn (Sr: 4c; Bi: 4d; Sr: 4d; Bi: 8e). 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 A3B2_oP20_52_de_cd-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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