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Crystal Lab › Prototype structures › Orthorhombic

Ga₂Mg₅ (D8_{g})

Orthorhombic · space group Ibam (No. 72) · Pearson oI28 · Strukturbericht D8g

Symmetry elements and Wyckoff positions (interactive)

Ga₂Mg₅ (D8_{g}) in Ibam

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

Unit cell

Lattice constants
a = 13.700 Å, b = 7.010 Å, c = 6.020 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
578.1 ų
Atoms in the conventional cell
28 (Mg 20, Ga 8)
Formula units Z
4
Pearson symbol
oI28 — orthorhombic, body-centred lattice, 28 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Mg2Mg4a40.00000.00000.2500
Mg3Mg8f80.76000.00000.2500
Ga1Ga8j80.62200.75500.0000
Mg4Mg8j80.57700.15500.0000

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 28 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

A2B5_oI28_72_j_afj-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oI28, then the space-group number 72, then the Wyckoff letters occupied by each element in turn (Mg: 4a; Mg: 8f; Ga: 8j; Mg: 8j). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

As₂Cu₅, In₂Mg₅, Tl₂Mg₅, Mn₂Ge₅ <!--beginning with an

Note: D8_{g}.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B5_oI28_72_j_afj-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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