The stability of [CCl4]+·, [Cl2CClCl]+·, their dications, and neutral counterparts

Electron impact ionization of tetrachloromethane has been shown to produce stable [CCl4]+· ions; their heat of formation is ⩽ 237 kcal mol−1. The ylid isomer, [Cl2CClCl]+·, generated upon dissociative ionization of Cl3CCOCl, is remarkably more stable; ΔH0f([Cl2CClCl]+·) < 224 kcal mol−1. The values for both isomers are significantly lower than calculated values. The corresponding neutrals, CCl4 and Cl2CClCl, are not stable on the time and energy scale of neutralization—re-ionization experiments. Although [Cl2CClCl]2+, was calculated to be stable, it was not present in the charge-stripping mass spectrum of the ylid ion.