What is "sulfonium"

n. (context chemistry English) the univalent H₃S⁺ cation, derived from sulfane

A sulfonium ion, also known as sulphonium ion or sulfanium ion, is a positively charged ion (a " cation") featuring three organic substituents attached to sulfur. These organosulfur compounds have the formula [SR]. Together with a negatively charged counterion, they give sulfonium salts. They are typically colorless solids that are soluble in organic solvent.