the two nitrogen atoms of the functional groups being doubly-bound to each other, e.g. azoformamide

Full Title

Derivatives of carbonic acid containing functional groups covered by groups C07C269/00 - C07C279/00 in which at least one nitrogen atom of these functional groups is further bound to another nitrogen atom not being part of a nitro or nitroso group > the two nitrogen atoms of the functional groups being doubly-bound to each other, e.g. azoformamide