sentence: Many minerals contain sulfur ions.
sentences_before: Sulfur can be found in the earth near volcanoes.
sentences_after: Coal contains sulfur ions which are released when it burns. Hydrogen sulfide and sulfur dioxide are some sulfur compounds that are released when coal burns. They are reacted to make sulfur.
concept_name: mineral
headings: Sulfur Occurrence and preparation
categories: Chemical elements Nonmetals