Noun
(inorganic chemistry) the univalent H3S cation, derived from sulfane
(organic chemistry) any derivative of this cation in which one or more hydrogen atoms are replaced by organic radicals
Source: en.wiktionary.orgMechanism of cellular toxicity The compound readily eliminates a chloride ion by intramolecular nucleophilic substitution to form a cyclic sulfonium ion. Source: Internet
SAM is composed of an adenosyl molecule (via 5' carbon) attached to the sulfur of methionine, therefore making it a sulfonium cation (i.e. three substituents and positive charge). Source: Internet