N-Oxoammonium salts are a class of organic compounds with the formula [RR=O]X. The cation [RR=O] is of interest for the dehydrogenation of alcohols.  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].  A less expensive analogue is Bobbitt's salt.