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Crystal Lab › Prototype structures › Orthorhombic

Refined Tl₂AlF₅ AlF₅Tl₂

Orthorhombic · space group Cmcm (No. 63) · Pearson oC32

Symmetry elements and Wyckoff positions (interactive)

Refined Tl₂AlF₅ in Cmcm

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

Unit cell

Lattice constants
a = 10.060 Å, b = 8.240 Å, c = 7.460 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
618.4 ų
Atoms in the conventional cell
32 (Al 4, F 20, Tl 8)
Formula units Z
4
Pearson symbol
oC32 — orthorhombic, base-centred lattice, 32 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Al1Al4a40.00000.00000.0000
F2F4c40.00000.05000.2500
F3F8e80.82000.00000.0000
F4F8f80.00000.23000.9700
Tl5Tl8g80.21000.30000.2500

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 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

AB5C2_oC32_63_a_cef_g-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 63, then the Wyckoff letters occupied by each element in turn (Al: 4a; F: 4c; F: 8e; F: 8f; Tl: 8g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: Refined K3₃.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB5C2_oC32_63_a_cef_g-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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