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Crystal Lab › Prototype structures › Orthorhombic

KHg₂

Orthorhombic · space group Imma (No. 74) · Pearson oI12

Symmetry elements and Wyckoff positions (interactive)

KHg₂ in Imma

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

Unit cell

Lattice constants
a = 5.160 Å, b = 8.100 Å, c = 8.770 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
366.6 ų
Atoms in the conventional cell
12 (K 4, Hg 8)
Formula units Z
4
Pearson symbol
oI12 — orthorhombic, body-centred lattice, 12 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
K2K4e40.00000.25000.9530
Hg1Hg8h80.00000.56000.6630

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_oI12_74_h_e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oI12, then the space-group number 74, then the Wyckoff letters occupied by each element in turn (K: 4e; Hg: 8h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

BaZn₂, CaAg₂, SrZn₂ <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B_oI12_74_h_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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