What is "cupferron"

n. (context organic chemistry English) The salt ''ammonium N-nitrosophenylhydroxylamine'' used to form complexes with metal ions

Cupferron, the ammonium salt of N-nitroso-N-phenylhydroxylamine, is a common reagent for the complexation of metal ions. Its formula is NH[CHN(O)NO]. The anion binds to metal cations through the two oxygen atoms, forming five-membered chelate rings.

Cupferron is prepared from phenylhydroxylamine and an NO source:

CHNHOH + CHONO + NH → NH[CHN(O)NO] + CHOH