Nitrogen), the mono-, diand trioxides being basic in character, the tetraand pentoxides being acidic and also feebly basic. The monoxide, V 2 0, is formed when the metal is oxidized slowly in air.
These acids are obtained by the reduction of the hydrobromides of the diand tetra-hydroterephthalic acids or by the action of ethylene dibromide on disodio-butane tetracarboxylic acid.
A r It is reduced by the action of zinc and ammonia to diand tetra-hydroquinolines.
On heating it gives the diand penta-chlorides.
It is obtained by condensing benzal chloride with mercury diphenyl (Kekule and Franchimont, Ber., 1872, 5, p. 907); from benzal chloride or benzotrichloride and zinc dust or aluminium chloride; from chloroform or carbon tetrachloride and benzene in the presence of aluminium chloride; and deamidating diand tri-aminotriphenylmethane with nitrous acid and alcohol (0.