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Crystal Lab › Prototype structures › Tetragonal

α-MgAgSb AgMgSb

Tetragonal · space group I-4c2 (No. 120) · Pearson tI48

Symmetry elements and Wyckoff positions (interactive)

α-MgAgSb in I-4c2

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

Unit cell

Lattice constants
a = 9.176 Å, b = 9.176 Å, c = 12.696 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
1069.0 ų
Atoms in the conventional cell
48 (Ag 16, Mg 16, Sb 16)
Formula units Z
16
Pearson symbol
tI48 — tetragonal, body-centred lattice, 48 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Ag1Ag4a40.00000.00000.2500
Ag2Ag4b40.00000.00000.0000
Ag3Ag8e80.22470.22470.2500
Mg4Mg16i16-0.03600.29600.0960
Sb5Sb16i160.23630.47490.1203

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 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

ABC_tI48_120_abe_i_i-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 120, then the Wyckoff letters occupied by each element in turn (Ag: 4a; Ag: 4b; Ag: 8e; Mg: 16i; Sb: 16i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: α-MgAgSb.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry ABC_tI48_120_abe_i_i-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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