Crystal Lab › Prototype structures › Orthorhombic
BN (High-pressure, high-temperature)
Orthorhombic · space group Fmm2 (No. 42) · Pearson oF8
Symmetry elements and Wyckoff positions (interactive)
BN (High-pressure, high-temperature) in Fmm2
SettingUnit cell
- Lattice constants
- a = 2.500 Å, b = 3.350 Å, c = 4.340 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 36.3 ų
- Atoms in the conventional cell
- 8 (B 4, N 4)
- Formula units Z
- 4
- Pearson symbol
- oF8 — orthorhombic, face-centred lattice, 8 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| B1 | B | 4a | 4 | 0.0000 | 0.0000 | 0.0000 |
| N2 | N | 4a | 4 | 0.0000 | 0.0000 | 0.3330 |
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
AB_oF8_42_a_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oF8, then the space-group number 42, then the Wyckoff letters occupied by each element in turn (B: 4a; N: 4a). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: HP.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_oF8_42_a_a-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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