sentence: Several fluorides are found in the earth, though.
sentences_after: When calcium phosphate is reacted with sulfuric acid to make phosphoric acid, some hydrofluoric acid is produced. Also, fluorite can be reacted with sulfuric acid to make hydrofluoric acid. Is a luiquid of fluoride U. Fluorine naturally occurs on the earths' crust in rocks, coal and clay.
concept_name: several fluoride
headings: Fluorine Occurrence
categories: Nonmetals Halogens