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Crystal Lab › Prototype structures › Tetragonal

CdAs₂

Tetragonal · space group I4122 (No. 98) · Pearson tI12

Symmetry elements and Wyckoff positions (interactive)

CdAs₂ in I4122

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

Unit cell

Lattice constants
a = 7.953 Å, b = 7.953 Å, c = 4.676 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
295.8 ų
Atoms in the conventional cell
12 (Cd 4, As 8)
Formula units Z
4
Pearson symbol
tI12 — tetragonal, body-centred lattice, 12 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Cd2Cd4a40.00000.00000.0000
As1As8f80.44000.25000.1250

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 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

A2B_tI12_98_f_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI12, then the space-group number 98, then the Wyckoff letters occupied by each element in turn (Cd: 4a; As: 8f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

CdAs_{2-x}P_{x} <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B_tI12_98_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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