Imine is a term used in organic chemistry to describe a molecule that contains a carbon-nitrogen double bond. As with many technical terms in chemistry, there are several synonyms for imine that may be used in different contexts. These include aldimine, ketimine, iminium ion, and Schiff base. Each of these synonyms describes a specific type of imine or a related molecule. Aldimines are imines formed from the reaction of an aldehyde with an amine, while ketimines are formed from the reaction of a ketone with an amine. Iminium ions are positively charged imine derivatives, while Schiff bases are imines that are formed from the reaction of a primary amine with a carbonyl compound.