sulfenic acid

Sulfenic acids are a series of monobasic organic acids of sulfur with the general formula RSOH. They are known almost exclusively in the form of their derivatives, such as acid halides and amides. Sulfenic acids and their salts are unstable compounds and are weaker than sulfinic acids, with a pKa of approximately 5. They are rarely isolated, but sulfenic acids with one or three carbon atoms are key intermediates formed when onions, garlic, and related plants are cut or crushed. Sulfenic acids are a type of organosulfur oxyacid, alongside sulfinic acids (RS(O)OH) and sulfonic acids (RSO₂OH).12