Thiospinel group

The thiospinel group is a group of sulfide minerals with a general formula AB2X4 where A is nominally a +2 metal, B is a +3 metal and X is -2 sulfide or similar anion (selenide or telluride). Thio refers to sulfur and spinel indicates their isometric spinel-like structure. As the chalcogens S, Se and Te are less electronegative than oxygen, the bonding in these materials is generally more covalent than in the oxospinels. Some are (magnetic) semiconductors but others display, at times complicated, metallic behavior, often coupled with equally complicated magnetic properties. The assignment of oxidation states is also not always as straightforward as in the more ionic oxocompounds, as is shown in the case of carrollite. Group members include: Cadmoindite - CdIn2S4 Carrollite - CuCo2S4 Fletcherite - Cu(Ni,Co)2S4 Greigite - FeFe2S4 Indite - FeIn2S4 Kalininite - ZnCr2S4 Linnaeite - CoCo2S4 Polydymite - NiNi2S4 Siegenite - (Ni,Co)3S4 Tyrrellite - Cu(Co,Ni)2Se4 Violarite - FeNi2S4