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Crystal Lab › Prototype structures › Orthorhombic

K3₃ (Tl₂AlF₅)

Orthorhombic · space group C2221 (No. 20) · Pearson oC32 · Strukturbericht K33

Symmetry elements and Wyckoff positions (interactive)

K3₃ (Tl₂AlF₅) in C2221

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

Unit cell

Lattice constants
a = 8.240 Å, b = 10.060 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
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Al1Al4a40.00000.00000.0000
F3F4a40.77000.00000.0000
F4F4a40.22000.00000.0000
F2F4b40.00000.96700.2500
F5F8c80.50000.31000.5400
Tl6Tl8c80.70000.21000.2500

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 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

AB5C2_oC32_20_a_2abc_c-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 20, then the Wyckoff letters occupied by each element in turn (Al: 4a; F: 4a; F: 4a; F: 4b; F: 8c; Tl: 8c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: K3₃.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB5C2_oC32_20_a_2abc_c-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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