Iron sulfide or iron sulphide can refer to range of chemical compounds composed of iron and sulfur.

Minerals

By increasing order of stability:

  • Iron(II) sulfide, FeS
  • Greigite, Fe<sub>3</sub>S<sub>4</sub> (cubic)
  • Pyrrhotite, Fe<sub>1−x</sub>S (where x = 0 to 0.2) (monoclinic or hexagonal)
  • Troilite, FeS, the endmember of pyrrhotite (hexagonal)
  • Mackinawite, Fe<sub>1+x</sub>S (where x = 0 to 0.1) (tetragonal)
  • Marcasite, orthorhombic FeS<sub>2</sub>
  • Pyrite, cubic FeS<sub>2</sub> (fool's gold)
  • Arsenopyrite (mispickel), FeAsS, or Fe(As-S), Fe(III) mixed arseno-sulfide (monoclinic)

Synthetic

  • Iron(III) sulfide, Fe<sub>2</sub>S<sub>3</sub>
  • Iron-sulfur clusters, includes both synthetic and biological

Biological

  • Iron–sulfur protein