It is found in the ground as the mineral pyrite. It is shiny like a metal, but it does not conduct electricity. It can make sparks when it is powdered (ground finely). It does not always contains sulfide ions; sometimes it contains a mixture of sulfide and sulfur. When it is exposed to oxygen in air, it forms acids which pollute streams and rivers. It reacts with acids such as hydrochloric acid to make hydrogen sulfide gas.
Natural minerals[change | change source]
By increasing order of stability:
- Iron(II) sulfide, FeS, the less stable amorphous form;
- Greigite, a form of iron(II,III) sulfide (Fe3S4), analog to magnetite, Fe3O4;
- Pyrrhotite, Fe1−xS (where x = 0 to 0.2), or Fe7S8;
- Troilite, FeS, the endmember of pyrrhotite;
- Mackinawite, Fe1+xS (where x = 0 to 0.1);
- Marcasite, or iron(II) disulfide, FeS2 (orthorhombic);
- Pyrite, or iron(II) disulfide, FeS2 (cubic), the more stable endmember, known as fool's gold.