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Crystal Lab › Prototype structures › Orthorhombic

Bi₂GeO₅

Orthorhombic · space group Cmc21 (No. 36) · Pearson oC32

Symmetry elements and Wyckoff positions (interactive)

Bi₂GeO₅ in Cmc21

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

Unit cell

Lattice constants
a = 15.690 Å, b = 5.492 Å, c = 5.383 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
463.9 ų
Atoms in the conventional cell
32 (Ge 4, O 20, Bi 8)
Formula units Z
4
Pearson symbol
oC32 — orthorhombic, base-centred lattice, 32 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Ge2Ge4a40.00000.68570.2000
O3O4a40.00000.58030.4908
Bi1Bi8b80.16760.21740.2500
O4O8b80.09490.13680.6482
O5O8b80.25410.47770.4621

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 32 atoms drawn above are these sites multiplied by all 8 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

A2BC5_oC32_36_b_a_a2b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC32, then the space-group number 36, then the Wyckoff letters occupied by each element in turn (Ge: 4a; O: 4a; Bi: 8b; O: 8b; O: 8b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Bi₂SiO₅ <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC5_oC32_36_b_a_a2b-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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