An example of a simple, well-studied sulfinic acid is phenylsulfinic acid. A commercially important sulfinic acid is thiourea dioxide, which is prepared by the oxidation of thiourea with hydrogen peroxide.
:(NH)CS + 2HO → (NH)(NH)CSOH + 2HO
Another commercially important sulfinic acid is hydroxymethyl sulfinic acid, which is usually employed as its sodium salt (HOCHSONa). Called Rongalite, this anion is also commercially useful as a reducing agent.