Crystal Lab › Prototype structures › Orthorhombic
Low Temperature Body-Centered Orthorhombic CH₃NH₃PbBr₃ Br₃CH₆NPb
Orthorhombic · space group Imma (No. 74) · Pearson oI192
Symmetry elements and Wyckoff positions (interactive)
Low Temperature Body-Centered Orthorhombic CH₃NH₃PbBr₃ in Imma
SettingUnit cell
- Lattice constants
- a = 11.692 Å, b = 8.445 Å, c = 8.223 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 811.9 ų
- Atoms in the conventional cell
- 192 (Pb 4, Br 12, C 16, H 144, N 16)
- Formula units Z
- 4
- Pearson symbol
- oI192 — orthorhombic, body-centred lattice, 192 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Pb17 | Pb | 4c | 4 | 0.2500 | 0.2500 | 0.2500 |
| Br1 | Br | 4e | 4 | 0.0000 | 0.2500 | 0.2050 |
| Br2 | Br | 8f | 8 | 0.7252 | 0.0000 | 0.0000 |
| C3 | C | 8h | 8 | 0.0000 | 0.1359 | 0.7195 |
| H5 | H | 8h | 8 | 0.0000 | 0.3252 | 0.8665 |
| H6 | H | 8h | 8 | 0.0000 | 0.1169 | 0.6030 |
| N15 | N | 8h | 8 | 0.0000 | 0.3062 | 0.7500 |
| C4 | C | 8i | 8 | 0.0687 | 0.2500 | 0.7500 |
| N16 | N | 8i | 8 | 0.9439 | 0.2500 | 0.7500 |
| H10 | H | 16j | 16 | 0.4163 | 0.8547 | 0.2212 |
| H11 | H | 16j | 16 | 0.5963 | 0.6453 | 0.2788 |
| H12 | H | 16j | 16 | 0.5963 | 0.7780 | 0.1424 |
| H13 | H | 16j | 16 | 0.5678 | 0.8531 | 0.2019 |
| H14 | H | 16j | 16 | 0.4322 | 0.5890 | 0.2676 |
| H7 | H | 16j | 16 | 0.4163 | 0.6734 | 0.1712 |
| H8 | H | 16j | 16 | 0.5963 | 0.8266 | 0.3288 |
| H9 | H | 16j | 16 | 0.4163 | 0.7220 | 0.3576 |
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 192 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
A3B4C36D4E_oI192_74_ef_hi_2h8j_hi_c-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oI192, then the space-group number 74, then the Wyckoff letters occupied by each element in turn (Pb: 4c; Br: 4e; Br: 8f; C: 8h; H: 8h; H: 8h; N: 8h; C: 8i; N: 8i; H: 16j; H: 16j; H: 16j; H: 16j; H: 16j; H: 16j; H: 16j; H: 16j). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: LT-BCO.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3B4C36D4E_oI192_74_ef_hi_2h8j_hi_c-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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