The principal chromophores are the azo, -N = N -, azoxy, = N 2 O, nitro, - N02, nitroso, - NO, and carbonyl, = CO, groups.
In acid solution, amines are obtained, in alkaline solution, azoxy, azo and hydrazo compounds, and in neutral solution hydroxylamino compounds.
By oxidizing agents they are converted into azoxy compounds, and by reducing agents into hydrazo compounds or amines.
Azoxy Compounds, R N O N R', are usually yellow or red crystalline solids which result from the reduction of nitro or nitroso compounds by heating them with alcoholic potash (preferably using methyl alcohol).
It combines with aromatic amines to form azocompounds, with arylhydroxylamines to form azoxy compounds, and with hydroxylamine it gives isodiazobenzene.