What is "iminium"

n. (context organic chemistry English) A form of quaternary ammonium cation derived from an imine, R₂C=N⁺R₂

An iminium salt or cation in organic chemistry has the general structure [RRC=NRR] and is as such a protonated or substituted imine. It is an intermediate in many organic reactions such as the Beckmann rearrangement, Vilsmeier-Haack reaction, Stephen reaction or the Duff reaction. The use of the alternative names imonium compounds and immonium compounds is discouraged.