The ethyl halides: Stable neutral and radical cation isomers [C2, H2, 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: [CH2CH2FH]+˙; [CH3ClCH2]+˙ (ΔHf° = 1012 kJ mol−1); [CH3CHClH]+˙ (ΔHf° = 971 kJ mol−1); [CH2CH2ClH]+˙; [CH3BrCH2]+˙ (ΔHf° = 1058 KJ mol−1); [CH3CHBrH]+˙ (ΔHf° = 995 kJ mol−1) and [CH2CH2BrH]+˙. Neutralization–reionization mass spectrometry, employing Xe as the electron transfer target gas and O2 as the target gas for reionization, indicated that the ylides CH3ClCH2 and CH3BrCH2 could not be generated by such means. However, the species CH3CHClH, CH2CH2ClH and CH2CH2BrH (and possibly CH3CHBrH) were unambiguously identified.