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Crystal Lab › Prototype structures › Orthorhombic

Bi₇(Fe,Ti)₆O₂₁ m = 6 Aurivillius

Orthorhombic · space group Fmm2 (No. 42) · Pearson oF136

Symmetry elements and Wyckoff positions (interactive)

Bi₇(Fe,Ti)₆O₂₁ m = 6 Aurivillius in Fmm2

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

Unit cell

Lattice constants
a = 5.470 Å, b = 57.551 Å, c = 5.492 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
1729.0 ų
Atoms in the conventional cell
136 (Bi 28, O 84, Fe 24)
Formula units Z
4
Pearson symbol
oF136 — orthorhombic, face-centred lattice, 136 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Bi1Bi4a40.00000.00000.0000
O8O4a40.00000.00000.6290
O9O8b80.25000.25000.2340
Bi2Bi8c80.00000.07370.9980
Bi3Bi8c80.00000.14730.9870
Bi4Bi8c80.00000.22510.9870
Fe5Fe8c80.00000.31380.0210
Fe6Fe8c80.00000.46710.0250
Fe7Fe8c80.00000.39540.0530
O10O8c80.00000.35600.0580
O11O8c80.00000.71200.0540
O12O8c80.00000.43400.1070
O13O16e160.69900.90200.8280
O14O16e160.72600.81200.7230
O15O16e160.29400.97200.8050

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 136 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

A7B6C21_oF136_42_a3c_3c_ab3c3e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oF136, then the space-group number 42, then the Wyckoff letters occupied by each element in turn (Bi: 4a; O: 4a; O: 8b; Bi: 8c; Bi: 8c; Bi: 8c; Fe: 8c; Fe: 8c; Fe: 8c; O: 8c; O: 8c; O: 8c; O: 16e; O: 16e; O: 16e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: m = 6 Aurivillius.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A7B6C21_oF136_42_a3c_3c_ab3c3e-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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