Aryldiazonium ion salt is produced by the reaction of a primary aromatic amine with nitrous acid. Both aryl amines and alkyl amines undergo this reaction, and follow the same mechanism.
These aryldiazonium ions (named as arendiazonium salts) are intermediates in the synthesis of a wide variety of compounds. For example, reaction with potassium iodide (KI), cuprous chloride (CuCl), cuprous bromide (CuBr), cuprous cyanide (CuCN), and water give aryl iodides, chlorides, bromides, cyanides, and phenols, respectively.