Skip to content

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

Setting
Loading the group…
x = 0.10, y = 0.17, z = 0.08

Unit 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

SiteElementWyckoffMultiplicityxyz
B1B4a40.00000.00000.0000
N2N4a40.00000.00000.3330

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.

← Bi₇(Fe,Ti)₆O₂₁ m = 6 Aurivillius  ·  Space group Fmm2 (3 prototypes)  ·  All prototypes