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Crystal Lab › Prototype structures › Tetragonal

Orange (I) HgI₂

Tetragonal · space group I41/amd (No. 141) · Pearson tI48

Symmetry elements and Wyckoff positions (interactive)

Orange (I) HgI₂ in I41/amd

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

Unit cell

Lattice constants
a = 8.786 Å, b = 8.786 Å, c = 24.667 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
1904.3 ų
Atoms in the conventional cell
48 (I 32, Hg 16)
Formula units Z
16
Pearson symbol
tI48 — tetragonal, body-centred lattice, 48 atoms per conventional cell
Symmetry operations
32 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
I2I8e80.00000.25000.7575
I3I8e80.00000.25000.2424
I4I16g160.23580.48580.8750
Hg1Hg16h160.00000.49790.3123

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 48 atoms drawn above are these sites multiplied by all 32 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

AB2_tI48_141_h_2eg-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI48, then the space-group number 141, then the Wyckoff letters occupied by each element in turn (I: 8e; I: 8e; I: 16g; Hg: 16h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: Orange (I) HgI₂.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2_tI48_141_h_2eg-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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