Iron sulfide

Iron sulfide or Iron sulphide refers to a chemical compound of iron and sulfur with a wide range of stoechiometric formulae and different crystalline structures.

Natural minerals

By increasing order of stability:

• Iron(II) sulfide, FeS, the less stable amorphous form;
• Troilite, FeS, the end member of pyrrhotite;
• Greigite, Fe₃S₄, analog to magnetite, Fe₃O₄;
• Pyrrhotite, Fe_1-xS (where x = 0 to 0.2), or Fe₇S₈;
• Mackinawite, Fe_1+xS (where x = 0 to 0.1);
• Marcasite, or iron(II) disulfide, FeS₂ (orthorhombic);
• Pyrite, or iron(II) disulfide, FeS₂ (cubic), the more stable end member.

Artificial product

• Iron(III) sulfide, Fe₂S₃, a quite unstable artificial product synthesised at –20 °C and not identified in nature.