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Crystal Lab › Prototype structures › Orthorhombic

GdSi₂

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

Symmetry elements and Wyckoff positions (interactive)

GdSi₂ in Imma

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

Unit cell

Lattice constants
a = 4.009 Å, b = 4.089 Å, c = 13.442 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
220.4 ų
Atoms in the conventional cell
12 (Gd 4, Si 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
Gd1Gd4e40.00000.25000.6250
Si2Si4e40.00000.25000.0488
Si3Si4e40.00000.25000.2142

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

AB2_oI12_74_e_2e-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 (Gd: 4e; Si: 4e; Si: 4e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

GeSi₂, HoSi₂, LaGe₂, TbSi₂, DySi_{1.4}, GdSi_{1.4}, NdSi_{1.4}, PrSi_{1.4}, SmSi_{1.4}, YSi_{1.4} <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2_oI12_74_e_2e-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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