Definition of sulfonium compounds

1. Compounds having the structure R3S+ and associated anion (generally, but not necessarily, all three R groups are hydrocarbyl). NOC Rule C-551.1. See under onium compounds. E.g. [(CH3)3S]+ Cl- trimethylsulfonium chloride, 1-thioniabicyclo[2.2.1]heptane brom