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
SettingUnit 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
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Fe1 | Fe | 4a | 4 | 0.5049 | 0.2419 | 0.0000 |
| S2 | S | 4a | 4 | 0.6150 | 0.1350 | 0.3834 |
| S3 | S | 4a | 4 | 0.6150 | 0.6350 | 0.1134 |
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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