Sulfide compounds are chemical substances that contain sulfur and one or more other elements, typically metals. They are characterized by the presence of the sulfide ion, S^2-, which gives these compounds their distinct properties. Common examples include iron sulfide (FeS) and copper sulfide (CuS), which are often found in nature and can be important in various industrial processes. These compounds can form through natural processes, such as volcanic activity, or through human activities, like mining. Sulfides can have significant environmental impacts, particularly when they oxidize to produce sulfuric acid, leading to acid mine drainage. Understanding sulfide compounds is essential for managing their effects on ecosystems and human health.