Cupferron is jargon for the ammonium salt of the conjugate base derived from N-nitroso-N-phenylhydroxylamine.

It once was a common reagent for the complexation of metal ions, being of interest in the area of qualitative inorganic analysis.

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:[1] Being a bidentate mono-anionic ligand, CU− forms complexes analogous to those produced with acetylacetonate.

[2][3][4] This article about an aromatic compound is a stub.