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Crystal Lab › Prototype structures › Tetragonal

α-ThCl₄ Cl₄Th

Tetragonal · space group I41/a (No. 88) · Pearson tI20

Symmetry elements and Wyckoff positions (interactive)

α-ThCl₄ in I41/a

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

Unit cell

Lattice constants
a = 6.408 Å, b = 6.408 Å, c = 12.924 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
530.7 ų
Atoms in the conventional cell
20 (Th 4, Cl 16)
Formula units Z
4
Pearson symbol
tI20 — tetragonal, body-centred lattice, 20 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Th2Th4a40.00000.25000.1250
Cl1Cl16f160.14700.01700.2980

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 20 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

A4B_tI20_88_f_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI20, then the space-group number 88, then the Wyckoff letters occupied by each element in turn (Th: 4a; Cl: 16f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

ThBr₄ <!--beginning with an

Note: α-ThCl₄.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A4B_tI20_88_f_a-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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