What is "peroxymonosulfuric acid"

Peroxymonosulfuric acid, (HSO), also known as persulfuric acid, peroxysulfuric acid, or Caro's acid, is a liquid at room temperature. In this acid, the S(VI) center adopts its characteristic tetrahedral geometry; the connectivity is indicated by the formula HO–O–S(O)–OH. It is one of the strongest oxidants known ( E = +2.51 V) and is highly explosive.

HSO is sometimes confused with HSO, known as peroxydisulfuric acid. The disulfuric acid, which appears to be more widely used as its alkali metal salts, has the structure HO–S(O)–O–O–S(O)–OH.