Which compound is formed with sulfur and has a lowest oxidation number of -2?

The compound formed with sulfur that has the lowest oxidation number of -2 is a sulfide. In this context, sulfide refers to compounds where sulfur exhibits an oxidation state of -2, which occurs when sulfur bonds with metals. For example, in hydrogen sulfide (H₂S) or metal sulfides like iron sulfide (FeS), sulfur takes on the -2 oxidation state.

In its -2 oxidation state, sulfur gains two electrons, which is typical when it forms ionic bonds with less electronegative elements. This is a common and stable form for sulfur, especially when it is combined with metals in mineral compounds.

The other options represent compounds where the sulfur is not in the -2 oxidation state. Hydrides involve hydrogen, and while they can have different charges, they do not involve sulfur in a -2 oxidation state. Oxides involve oxygen, and though sulfur can bond with oxygen, it doesn't exhibit a -2 state in oxides as oxygen typically has a -2 oxidation state itself. Lastly, nitrides pertain to combinations of elements with nitrogen, not sulfur. Therefore, sulfides are the specific compounds that allow sulfur to achieve its lowest oxidation state of -2.