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The crystallographic unit cell is cubic, with space group Fd3m. The S anions form a cubic close-packed lattice, and the Fe cations occupy both tetrahedral and octahedral sites.
Crystal structure of iron(II,III) sulfide projected along the direction
Emphasis on the SFe4 tetrahedra.
Emphasis on the FeS4 tetrahedra
Emphasis on the FeS6 octahedra
Magnetic and electronic properties
Like the related oxide magnetite (Fe3O4), iron(II,III) sulfide is ferrimagnetic, with the spin magnetic moments of the Fe centers in the tetrahedral sites oriented in the opposite direction as those in the octahedral sites, and a net magnetization. Both metal sites have high spin quantum numbers. The electronic structure of greigite is that of a half metal.
References
Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C., eds. (1990). "Greigite" (PDF). Handbook of Mineralogy. Vol. I (Elements, Sulfides, Sulfosalts). Chantilly, VA, US: Mineralogical Society of America. ISBN978-0962209703. Retrieved December 5, 2011.
Vaughan, D. J.; Craig, J. R. “Mineral Chemistry of Metal Sulfides" Cambridge University Press, Cambridge: 1978. ISBN0-521-21489-0.
Wang, Jun; Cao, Shi-He; Wu, Wei; Zhao, Guo-Meng (2011). "The Curie temperature and magnetic exchange energy in half-metallic greigite Fe3S4". Physica Scripta. 83 (4): 045702. Bibcode:2011PhyS...83d5702W. doi:10.1088/0031-8949/83/04/045702.
Stanjek, H.; Fassbinder, J. W. E.; Vali, H.; Wagele, H.; Graf, W. (1994). "Evidence of biogenic greigite (ferrimagnetic Fe3S4) in soil". European Journal of Soil Science. 45 (2): 97–103. doi:10.1111/j.1365-2389.1994.tb00490.x.