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Room Temperature Perovskite CH₃NH₃PbBr₃ Br₃CH₆NPb
Cubic · space group Pm-3m (No. 221) · Pearson cP172
Symmetry elements and Wyckoff positions (interactive)
Room Temperature Perovskite CH₃NH₃PbBr₃ in Pm-3m
SettingUnit cell
- Lattice constants
- a = 5.926 Å, b = 5.926 Å, c = 5.926 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 208.1 ų
- Atoms in the conventional cell
- 172 (Pb 1, Br 3, C 12, N 12, H 144)
- Formula units Z
- 1
- Pearson symbol
- cP172 — cubic, primitive lattice, 172 atoms per conventional cell
- Symmetry operations
- 48 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Pb8 | Pb | 1b | 1 | 0.5000 | 0.5000 | 0.5000 |
| Br1 | Br | 3c | 3 | 0.0000 | 0.5000 | 0.5000 |
| C2 | C | 12i | 12 | 0.0000 | 0.9416 | 0.9416 |
| N7 | N | 12i | 12 | 0.0000 | 0.1084 | 0.1084 |
| H3 | H | 24k | 24 | 0.0000 | 0.0570 | 0.2390 |
| H4 | H | 24k | 24 | 0.0000 | 0.0270 | 0.7780 |
| H5 | H | 48n | 48 | 0.1480 | 0.2110 | 0.0840 |
| H6 | H | 48n | 48 | 0.8520 | 0.8350 | 0.9540 |
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 172 atoms drawn above are these sites multiplied by all 48 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
A3B12C144D12E_cP172_221_c_i_2k2n_i_b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol cP172, then the space-group number 221, then the Wyckoff letters occupied by each element in turn (Pb: 1b; Br: 3c; C: 12i; N: 12i; H: 24k; H: 24k; H: 48n; H: 48n). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: RT-Perovskite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3B12C144D12E_cP172_221_c_i_2k2n_i_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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