Peroxymonosulfuric acid

Ball-and-stick model of peroxymonosulfuric acid.

Peroxymonosulfuric acid is a chemical compound with the formula H
2SO
5. It is a peroxy acid closely related to sulfuric acid. It was discovered by the German chemist Heinrich Caro, so it is sometimes called Caro's acid. Salts of peroxymonosulfuric acid are called peroxymonosulfates.

Peroxymonosulfuric acid is a strong oxidizer. It is one of the active chemical species in piranha solution.