Crystal Lab › Prototype structures › Orthorhombic
Marcasite (FeS₂, C18)
Orthorhombic · space group Pnnm (No. 58) · Pearson oP6 · Strukturbericht C18 · mineral: marcasite
Symmetry elements and Wyckoff positions (interactive)
Marcasite (FeS₂, C18) in Pnnm
SettingUnit cell
- Lattice constants
- a = 4.445 Å, b = 5.425 Å, c = 3.386 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 81.6 ų
- Atoms in the conventional cell
- 6 (Fe 2, S 4)
- Formula units Z
- 2
- Pearson symbol
- oP6 — orthorhombic, primitive lattice, 6 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Fe1 | Fe | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| S2 | S | 4g | 4 | 0.2004 | 0.3787 | 0.0000 |
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 6 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
AB2_oP6_58_a_g-003: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP6, then the space-group number 58, then the Wyckoff letters occupied by each element in turn (Fe: 2a; S: 4g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
BeH₂, CoAs₂, CoSb₂, CoSe₂, CoTe₂, CrSb₂, CuS₂, CuSe₂, FeAs₂, FeP₂, FeS₂, FeSb₂, FeSe₂, FeTe₂, MnS₂, NiAs₂ (rammelsbergite), NiS₂, NiSb₂, NiSe₂, OsAs₂, OsP₂, OsSb₂, PdI₂, RuAs₂, RuP₂, RuSb₂, RuTe₂, TiS₂ <!--beginning with an
Note: C18, Marcasite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2_oP6_58_a_g-003 (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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