Evidence for the existence of phosphoazonium (iminophosphenium) and arsenoazonium ions in the gas phase by mass spectrometry

The first evidence for the existence of the methylphosphoazonium (methyliminophosphenium) ion CH 3 NP + and the methylarsenoazonium ion (named in this work) CH 3 NAs + (analogues of the methyldiazonium ion CH 3 NN + ) is provided using electron impact mass spectrometry The ions are formed as fragment ions of some highly air‐sensitive phospholidinium and arsolidinium compounds that contain dicoordinate P and As centres. A combination of high‐resolution mass measurements and high‐ and low‐energy tandem mass spectra (fragment ion scans) suggest that the ions have NC bonds rather than the isomeric azophosphonium (CH 3 PN + ) or azoarsenonium (CH 3 AsN + ) forms.