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Crystal Lab › Prototype structures › Tetragonal

θ-AlF₃

Tetragonal · space group P4/nmm (No. 129) · Pearson tP64

Symmetry elements and Wyckoff positions (interactive)

θ-AlF₃ in P4/nmm

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

Unit cell

Lattice constants
a = 10.184 Å, b = 10.184 Å, c = 7.173 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
744.0 ų
Atoms in the conventional cell
64 (Al 16, F 48)
Formula units Z
16
Pearson symbol
tP64 — tetragonal, primitive lattice, 64 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Al1Al2c20.25000.25000.9068
Al2Al2c20.25000.25000.4137
F5F2c20.25000.25000.1573
F6F2c20.25000.25000.6645
Al3Al4d40.00000.00000.0000
F7F4f40.75000.25000.2433
F8F8h80.12620.87380.5000
Al4Al8i80.25000.91380.3274
F9F8i80.25000.07700.4130
F10F8j80.12800.12800.9077
F11F16k160.12230.94780.1610

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 64 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

AB3_tP64_129_2cdi_2cfhijk-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP64, then the space-group number 129, then the Wyckoff letters occupied by each element in turn (Al: 2c; Al: 2c; F: 2c; F: 2c; Al: 4d; F: 4f; F: 8h; Al: 8i; F: 8i; F: 8j; F: 16k). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: \theta-AlF₃.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB3_tP64_129_2cdi_2cfhijk-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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