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Crystal Lab › Prototype structures › Orthorhombic

Low Temperature Pyrite (FeS₂)

Orthorhombic · space group Pca21 (No. 29) · Pearson oP12 · mineral: pyrite

Symmetry elements and Wyckoff positions (interactive)

Low Temperature Pyrite (FeS₂) in Pca21

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

Unit cell

Lattice constants
a = 5.418 Å, b = 5.418 Å, c = 5.418 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
159.0 ų
Atoms in the conventional cell
12 (Fe 4, S 8)
Formula units Z
4
Pearson symbol
oP12 — orthorhombic, primitive lattice, 12 atoms per conventional cell
Symmetry operations
4 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Fe1Fe4a40.50490.24190.0000
S2S4a40.61500.13500.3834
S3S4a40.61500.63500.1134

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 12 atoms drawn above are these sites multiplied by all 4 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_oP12_29_a_2a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP12, then the space-group number 29, then the Wyckoff letters occupied by each element in turn (Fe: 4a; S: 4a; S: 4a). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: LT Pyrite.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2_oP12_29_a_2a-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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