Halonium ion

A halonium ion is any onium compound (ion) containing a halogen atom carrying a positive charge. This cation has the general structure R−+X−R′ where X is any halogen and no restrictions on R, this structure can be cyclic or an open chain molecular structure. Halonium ions formed from fluorine, chlorine, bromine, and iodine are called fluoronium, chloronium, bromonium, and iodonium, respectively. The cyclic variety commonly proposed as intermediates in electrophilic halogenation may be called haliranium ions, using the Hantzch-Widman nomenclature system. A halonium ion is any onium compound (ion) containing a halogen atom carrying a positive charge. This cation has the general structure R−+X−R′ where X is any halogen and no restrictions on R, this structure can be cyclic or an open chain molecular structure. Halonium ions formed from fluorine, chlorine, bromine, and iodine are called fluoronium, chloronium, bromonium, and iodonium, respectively. The cyclic variety commonly proposed as intermediates in electrophilic halogenation may be called haliranium ions, using the Hantzch-Widman nomenclature system. The simplest halonium ions are of the structure H−+X−H (X = F, Cl, Br, I). Halonium ions often have a three-atom cyclic structure, similar to that of an epoxide, resulting from the formal addition of a halogenium ion X+ to a C=C double bond, as when a halogen is added to an alkene.