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Crystal Lab › Prototype structures › Orthorhombic

Low Temperature FeSi₂ FeSi_2

Orthorhombic · space group Cmce (No. 64) · Pearson oC48

Symmetry elements and Wyckoff positions (interactive)

Low Temperature FeSi₂ in Cmce

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

Unit cell

Lattice constants
a = 9.863 Å, b = 7.791 Å, c = 7.833 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
601.9 ų
Atoms in the conventional cell
48 (Fe 16, Si 32)
Formula units Z
16
Pearson symbol
oC48 — orthorhombic, base-centred lattice, 48 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Fe1Fe8d80.21460.00000.0000
Fe2Fe8f80.00000.80860.1851
Si3Si16g160.12820.27460.0512
Si4Si16g160.87270.54500.2279

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

AB2_oC48_64_df_2g-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC48, then the space-group number 64, then the Wyckoff letters occupied by each element in turn (Fe: 8d; Fe: 8f; Si: 16g; Si: 16g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: T < 962K.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2_oC48_64_df_2g-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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