Crystal Lab › Prototype structures › Orthorhombic
Cu₂Pb(SeO₃)₂Br₂
Orthorhombic · space group Cmcm (No. 63) · Pearson oC52
Symmetry elements and Wyckoff positions (interactive)
Cu₂Pb(SeO₃)₂Br₂ in Cmcm
SettingUnit 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
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Pb5 | Pb | 4c | 4 | 0.0000 | 0.3350 | 0.2500 |
| Cu2 | Cu | 8e | 8 | 0.1862 | 0.0000 | 0.0000 |
| O3 | O | 8f | 8 | 0.0000 | 0.1287 | 0.5177 |
| Se6 | Se | 8f | 8 | 0.0000 | 0.3122 | 0.5404 |
| Br1 | Br | 8g | 8 | 0.2277 | 0.0772 | 0.2500 |
| O4 | O | 16h | 16 | 0.6531 | 0.8602 | 0.4531 |
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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