The ethyl halides: Stable neutral and radical cation isomers [C 2 , H 2 , X] where X = F, Cl, Br, I

The following isomers of the ethyl halide molecular ions have all been shown to be stable species in the gas phase: [CH 2 CH 2 FH] + ˙; [CH 3 ClCH 2 ] + ˙ (ΔH f ° = 1012 kJ mol −1 ); [CH 3 CHClH] + ˙ (ΔH f ° = 971 kJ mol −1 ); [CH 2 CH 2 ClH] + ˙; [CH 3 BrCH 2 ] + ˙ (ΔH f ° = 1058 KJ mol −1 ); [CH 3 CHBrH] + ˙ (ΔH f ° = 995 kJ mol −1 ) and [CH 2 CH 2 BrH] + ˙. Neutralization–reionization mass spectrometry, employing Xe as the electron transfer target gas and O 2 as the target gas for reionization, indicated that the ylides CH 3 ClCH 2 and CH 3 BrCH 2 could not be generated by such means. However, the species CH 3 CHClH, CH 2 CH 2 ClH and CH 2 CH 2 BrH (and possibly CH 3 CHBrH) were unambiguously identified.