N-Oxoammonium salts are a class of organic compounds with the formula [R1R2+N=O]X−.
Oxoammonium salts are diamagnetic, whereas the nitroxide has a doublet ground state.
A prominent N-oxoammonium salt is prepared by oxidation of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl, commonly referred to as [TEMPO]+.
Oxoammonium cations are isoelectronic with carbonyls and structurally related to aldoximes (hydroxylamines), and aminoxyl (nitroxide) radicals, with which they can interconvert via a series of redox steps.
The nitroxyl TEMPO reacts via its N-oxoammonium salt.