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BaGe₂As₂

Tetragonal · space group P42mc (No. 105) · Pearson tP20

Symmetry elements and Wyckoff positions (interactive)

BaGe₂As₂ in P42mc

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

Unit cell

Lattice constants
a = 7.786 Å, b = 7.786 Å, c = 8.664 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
525.2 ų
Atoms in the conventional cell
20 (Ba 4, Ge 8, As 8)
Formula units Z
4
Pearson symbol
tP20 — tetragonal, primitive lattice, 20 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Ba2Ba2b20.50000.50000.0000
Ba3Ba2c20.00000.50000.0241
Ge4Ge4d40.83510.00000.8640
Ge5Ge4d40.66320.00000.1068
As1As8f80.72900.74530.2558

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 20 atoms drawn above are these sites multiplied by all 8 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

A2BC2_tP20_105_f_bc_2d-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP20, then the space-group number 105, then the Wyckoff letters occupied by each element in turn (Ba: 2b; Ba: 2c; Ge: 4d; Ge: 4d; As: 8f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

BaGe₂P₂ <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC2_tP20_105_f_bc_2d-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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