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Crystal Lab › Prototype structures › Tetragonal

α-CuAlCl₄ AlCl₄Cu

Tetragonal · space group P-42c (No. 112) · Pearson tP12

Symmetry elements and Wyckoff positions (interactive)

α-CuAlCl₄ in P-42c

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

Unit cell

Lattice constants
a = 5.441 Å, b = 5.441 Å, c = 10.113 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
299.4 ų
Atoms in the conventional cell
12 (Al 2, Cu 2, Cl 8)
Formula units Z
2
Pearson symbol
tP12 — tetragonal, primitive lattice, 12 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Al1Al2b20.50000.00000.2500
Cu3Cu2e20.00000.00000.0000
Cl2Cl8n80.23340.27610.6295

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 12 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

AB4C_tP12_112_b_n_e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP12, then the space-group number 112, then the Wyckoff letters occupied by each element in turn (Al: 2b; Cu: 2e; Cl: 8n). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

α-CuAlBr₄, α-CuAlCl₂Br₂, α-CuAlCl₃Br, α-CuAlClBr₃, α-CuGaBr₄, α-CuGaCl₄ <!--beginning with an

Note: α-CuAlCl₄.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB4C_tP12_112_b_n_e-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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