Diazonium compounds or diazonium salts are a group of organic compounds sharing a common functional group R−N+
2X− where R can be any organic group, such as an alkyl or an aryl, and X is an inorganic or organic anion, such as a halogen. Diazonium salts, especially those where R is an aryl group, are important intermediates in the organic synthesis of azo dyes.