A colourless crystalline aromatic compound, (C₆H₅)₂NH; m.p. 54°C. It is made by heating phenylamine (aniline) with phenylamine hydrochloride. It is a secondary amine and is both slightly acidic (forming an N-potassium salt) and slightly basic (forming salts with mineral acids). Its derivatives are employed as stabilizers for synthetic rubber and rocket fuels.