By the addition of potassium bromide and bromine water to diazonium salts they are converted into a perbromide, e.g.

Oxyazo Compounds.—The oxyazo compounds are prepared by adding a solution of a diazonium salt to a cold slightly alkaline solution of a phenol.

Approximately 500 g. of cracked ice are added, and then, with mechanical stirring, the diazonium salt solution is run in as rapidly as possible.