These are group of metallic compounds that have sulfur in them. The usually have molecular formula of M₃S₂, Cu₂S, FeS₂.
Metallic sulfides are very important since they serve as reservoirs for sulfur atom and can be easily extracted from the ores. This is possible because they're usually cheap and abundant in nature. Eg Ni₃S₂, FeS₂, Cu₂S etc.
