Isomeric [C,H 3 ,N,O] + ˙ ions and their neutral counterparts

The isomeric ions [H 2 NC(H)O] + ˙, [H 2 NCOH] + ˙, [H 3 CNO] + ˙ and [H 2 CNOH] + ˙ were examined in the gas phase by mass spectrometry. Ab initio molecular orbital theory was used to calculate the relative stabilities of [H 2 NC(H)O] + ˙, [H 2 NCOH] + ˙, [H 3 NCO] + ˙ and their neutral counterparts. Theory predicted [H 2 NC(H)O] + ˙ to be the most stable ion. [H 2 NCOH] + ˙ ions were generated via a 1,4‐hydrogen transfer in [H 2 NC(O)OCH 3 ] + ˙, [H 2 NC(O)C(O)OH] + ˙ and [H 2 NC(O)CH 2 CH 3 ] + ˙. Its metastable dissociation takes place via [H 3 NCO] + ˙ with the isomerization as the rate‐determining step. [H 2 CNOH] + ˙ undergoes a rate‐determining isomerization into [H 3 CNO] + ˙ prior to metastable fragmentation. Neutralization‐reionization mass spectrometry was used to identify the neutral counterparts of these [H 3 ,C,N,O] + ˙ ions as stable species in the gas phase. The ion [H 3 NCO] + ˙ was not independently generated in these experiments; its neutral counterpart was predicted by theory to be only weakly bound.