Sulfur trioxide

Sulfur trioxide (sometimes spelled sulphur trioxide) is a chemical substance made of 1 sulfur and 3 oxygen atoms (SO₃). It is very toxic and irritating. It can dissolve violently in water to make sulfuric acid. It is made by oxidation of sulfur dioxide. It contains sulfur in its +6 oxidation state.

In popular culture

Sulfur trioxide is mentioned in the Emergency! episode "The Old Engine Cram".