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Crystal Lab › Prototype structures › Orthorhombic

γ-SeO₂ O₂Se

Orthorhombic · space group Pmc21 (No. 26) · Pearson oP24

Symmetry elements and Wyckoff positions (interactive)

γ-SeO₂ in Pmc21

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

Unit cell

Lattice constants
a = 5.071 Å, b = 4.483 Å, c = 14.967 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
340.3 ų
Atoms in the conventional cell
24 (O 16, Se 8)
Formula units Z
8
Pearson symbol
oP24 — orthorhombic, primitive lattice, 24 atoms per conventional cell
Symmetry operations
4 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
O1O2a20.00000.47600.3370
O2O2a20.00000.02700.0900
Se7Se2a20.00000.10700.6894
Se8Se2a20.00000.34400.4369
O3O2b20.50000.61700.4860
O4O2b20.50000.16600.2250
Se10Se2b20.50000.51100.2492
Se9Se2b20.50000.02700.0000
O5O4c40.25400.62400.1760
O6O4c40.24800.06100.4190

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 24 atoms drawn above are these sites multiplied by all 4 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

A2B_oP24_26_2a2b2c_2a2b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP24, then the space-group number 26, then the Wyckoff letters occupied by each element in turn (O: 2a; O: 2a; Se: 2a; Se: 2a; O: 2b; O: 2b; Se: 2b; Se: 2b; O: 4c; O: 4c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: \gamma-SeO₂.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B_oP24_26_2a2b2c_2a2b-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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