Iron(II,III) sulfide

Iron(II,III) sulfide

Names
Other names Ferrous-ferric sulfide, greigite
Properties
Chemical formula	FeS·Fe2S3
Molar mass	295.805
Appearance	Bluish-black, pinkish
Density	4.049 g/cm^3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Iron(II,III) sulfide is a blue-black (sometimes pinkish) chemical compound of iron and sulfur with formula Fe₃S₄ or FeS·Fe₂S₃, which is much similar to iron(II,III) oxide. It occurs naturally as the sulfide mineral greigite and is magnetic. It is a bio-mineral produced by and found in magnetotactic bacteria. It is a mixed valence compound, featuring both Fe²⁺ and Fe³⁺ centers, in 1:2 ratio.

Crystal structure

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.^[1][2]

Crystal structure of iron(II,III) sulfide projected along the [110] 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 cations 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.^[3][4]

References

1. Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W. and Nichols, Monte C., ed. (1990). "Greigite". Handbook of Mineralogy (PDF). I (Elements, Sulfides, Sulfosalts). Chantilly, VA, US: Mineralogical Society of America. ISBN 0962209708. Retrieved December 5, 2011.
2. Vaughan, D. J.; Craig, J. R. “Mineral Chemistry of Metal Sulfides" Cambridge University Press, Cambridge: 1978. ISBN 0-521-21489-0.
3. Devey, Anthony; R. Grau-Crespo and N.H. de Leeuw (2009). "Electronic and magnetic structure of Fe₃S₄: GGA+U investigation". Physical Review B 79 (19): 195126. Bibcode:2009PhRvB..79s5126D. doi:10.1103/PhysRevB.79.195126. Cite uses deprecated parameter |coauthors= (help)
4. 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.

Further reading

• Mann, Stephen; Sparks, Nicholas H. C.; Frankel, Richard B.; Bazylinski, Dennis A.; Jannasch, Holger W. (1990). "Biomineralization of ferrimagnetic greigite (Fe₃S₄) and iron pyrite (FeS₂) in a magnetotactic bacterium". Nature 343 (6255): 258. Bibcode:1990Natur.343..258M. doi:10.1038/343258a0.
• Roberts, A (1995). "Magnetic properties of sedimentary greigite (Fe₃S₄)". Earth and Planetary Science Letters 134: 227. Bibcode:1995E&PSL.134..227R. doi:10.1016/0012-821X(95)00131-U.
• Heywood, B. R.; Bazylinski, D. A.; Garratt-Reed, A.; Mann, S.; Frankel, R. B. (1990). "Controlled biosynthesis of greigite (Fe₃S₄) in magnetotactic bacteria". Naturwissenschaften 77: 536. Bibcode:1990NW.....77..536H. doi:10.1007/BF01139266.
• Reynolds, R. L.; Tuttle, M. L.; Rice, C. A.; Fishman, N. S.; Karachewski, J. A.; Sherman, D. M. (1994). "Magnetization and geochemistry of greigite-bearing Cretaceous strata, North Slope basin, Alaska". American Journal of Science 294: 485. doi:10.2475/ajs.294.4.485.
• Snowball, Ian; Thompson, Roy (1988). "The occurrence of Greigite in sediments from Loch Lomond". Journal of Quaternary Science 3: 121. Bibcode:1988JQS.....3..121S. doi:10.1002/jqs.3390030203.
• 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: 97. doi:10.1111/j.1365-2389.1994.tb00490.x.
• Hoffmann, V (1992). "Greigite (Fe₃S₄): magnetic properties and first domain observations". Physics of the Earth and Planetary Interiors 70: 288. Bibcode:1992PEPI...70..288H. doi:10.1016/0031-9201(92)90195-2.
• Fassbinder, Jörg W. E.; Stanjek, Helge (1994). "Magnetic properties of biogenic soil greigite (Fe₃S₄)". Geophysical Research Letters 21: 2349. Bibcode:1994GeoRL..21.2349F. doi:10.1029/94GL02506.