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Crystal Lab › Prototype structures › Orthorhombic

BaIr₂Ge₇

Orthorhombic · space group Cmmm (No. 65) · Pearson oC96

Symmetry elements and Wyckoff positions (interactive)

BaIr₂Ge₇ in Cmmm

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

Unit cell

Lattice constants
a = 37.656 Å, b = 6.441 Å, c = 6.400 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
1552.3 ų
Atoms in the conventional cell
96 (Ba 8, Ge 72, Ir 16)
Formula units Z
8
Pearson symbol
oC96 — orthorhombic, base-centred lattice, 96 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Ba1Ba2a20.00000.00000.0000
Ba2Ba2c20.50000.00000.5000
Ba3Ba4g40.64330.00000.0000
Ge4Ge4g40.53340.00000.0000
Ir11Ir4g40.09820.00000.0000
Ir12Ir4g40.21150.00000.0000
Ge5Ge4h40.03270.00000.5000
Ir13Ir4h40.59790.00000.5000
Ir14Ir4h40.70930.00000.5000
Ge6Ge8o80.15290.00000.2161
Ge7Ge8q80.15250.28160.5000
Ge8Ge16r160.07210.24920.2519
Ge9Ge16r160.22210.36500.1420
Ge10Ge16r160.22120.13500.3620

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 96 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

AB9C2_oC96_65_acg_ghoq3r_2g2h-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC96, then the space-group number 65, then the Wyckoff letters occupied by each element in turn (Ba: 2a; Ba: 2c; Ba: 4g; Ge: 4g; Ir: 4g; Ir: 4g; Ge: 4h; Ir: 4h; Ir: 4h; Ge: 8o; Ge: 8q; Ge: 16r; Ge: 16r; Ge: 16r). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB9C2_oC96_65_acg_ghoq3r_2g2h-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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