Structure of the bromonium ion from cyclopentene.
In organic chemistry, a halonium ion is an onium compound containing a halogen atom carrying a positive electrical charge. This cation has the generic structure R-X-R, where X is halogen and R is an organic residue or open organic molecular chain. Halonium ions are formed with fluorine, chlorine, bromine and iodine, respectively called fluoronium, chloronium, bromonium and iodonium. The simplest halonium ions have an H-X-H structure, with X = F, Cl, Br, I. They often have a triatomic ring structure resulting from the formal addition of a halogenium ion X to a C double bond = C. Notes and edit the code
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