Sulfur itself is an element, meaning it's made up of only one type of atom. It's a pure substance, not a compound, and doesn't contain anything else.

However, sulfur can combine with other elements to form compounds. Here are some examples:

* Sulfur dioxide (SO2): Found in volcanic emissions and contributes to acid rain.

* Sulfur trioxide (SO3): A major component of acid rain.

* Hydrogen sulfide (H2S): A colorless gas with a rotten egg smell, often found in natural gas and sewage.

* Sulfuric acid (H2SO4): A strong acid used in various industrial processes.

* Sulfates (SO42-): Salts containing sulfur and oxygen, often found in minerals like gypsum.

* Sulfides (S2-): Compounds where sulfur is combined with a metal, like iron sulfide (FeS).

So, while sulfur itself is a single element, it can be found in many different forms and compounds.