Topic summary
Sulfides
Extracted from the Wikipedia article Sulfide.
Disulfides
Confusion arises from the different meanings of the term "disulfide". Molybdenum disulfide (MoS2) consists of separated sulfide centers, in association with molybdenum in the formal +4 oxidation state (that is, Mo and two S). Iron disulfide (pyrite, FeS2) on the other hand consists of S2−2, or S−S dianion, in association with divalent iron in the formal +2 oxidation state (ferrous ion: Fe).