出典:Wiktionary
出典:Wikipedia
出典:『Wikipedia』 (2011/06/16 00:35 UTC 版)
Greigite is an iron sulfide mineral with formula Fe3S4. Like the related oxide magnetite (Fe3O4), greigite is magnetic. It is a mixed-valence compound, featuring both Fe(II) and Fe(III) centers in a 1:2 ratio. Both metal sites, which conform to the thiospinel motif, are high spin. Greigite occurs as microscopic (< 0.03 mm) isometric hexoctahedral crystals and as minute sooty masses. It is a bio-mineral produced by and found in magnetotactic bacteria.