A sulfide is a chemical compound that consists of sulfur and one or more metals or nonmetals. In these compounds, sulfur typically has a -2 oxidation state, meaning it gains two electrons. Common examples of sulfides include iron sulfide (FeS) and copper sulfide (CuS), which are often found in nature as minerals. Sulfides can be formed through various processes, including volcanic activity and the decomposition of organic matter. They are important in industries such as mining and metallurgy, where they are extracted for their metal content. Additionally, some sulfides have distinct odors, often reminiscent of rotten eggs, due to the presence of hydrogen sulfide (H₂S).