Crystal Lab › Prototype structures › Orthorhombic
Black Phosphorus (A17)
Orthorhombic · space group Cmce (No. 64) · Pearson oC8 · Strukturbericht A17
Symmetry elements and Wyckoff positions (interactive)
Black Phosphorus (A17) in Cmce
SettingUnit cell
- Lattice constants
- a = 3.314 Å, b = 10.478 Å, c = 4.376 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 151.9 ų
- Atoms in the conventional cell
- 8 (P 8)
- Formula units Z
- 8
- Pearson symbol
- oC8 — orthorhombic, base-centred lattice, 8 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| P1 | P | 8f | 8 | 0.0000 | 0.1017 | 0.0806 |
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 8 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
A_oC8_64_f-002: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC8, then the space-group number 64, then the Wyckoff letters occupied by each element in turn (P: 8f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: A17, Black Phosphorus.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A_oC8_64_f-002 (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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