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Cu₂Pb(SeO₃)₂Br₂

Orthorhombic · space group Cmcm (No. 63) · Pearson oC52

Symmetry elements and Wyckoff positions (interactive)

Cu₂Pb(SeO₃)₂Br₂ in Cmcm

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

Unit cell

Lattice constants
a = 8.275 Å, b = 9.303 Å, c = 11.891 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
915.4 ų
Atoms in the conventional cell
52 (Pb 4, Cu 8, O 24, Se 8, Br 8)
Formula units Z
4
Pearson symbol
oC52 — orthorhombic, base-centred lattice, 52 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Pb5Pb4c40.00000.33500.2500
Cu2Cu8e80.18620.00000.0000
O3O8f80.00000.12870.5177
Se6Se8f80.00000.31220.5404
Br1Br8g80.22770.07720.2500
O4O16h160.65310.86020.4531

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 52 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

A2B2C6DE2_oC52_63_g_e_fh_c_f-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC52, then the space-group number 63, then the Wyckoff letters occupied by each element in turn (Pb: 4c; Cu: 8e; O: 8f; Se: 8f; Br: 8g; O: 16h). 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 A2B2C6DE2_oC52_63_g_e_fh_c_f-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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