Free Radicals by Mass Spectrometry XLIV. Ionization Potentials and Bond Dissociation Energies for Chloro‐ and Fluoro‐Methyl Radicals

Using monoenergetic electron impact, ionization thresholds have been re‐measured for chloro‐ and fluoro‐methyl radicals produced in a silica furnace. The following ionization potentials have been obtained (in volts): CH2Cl 8.80, CHCl2 8.45, CCl3 8.28, CH2F 8.90. For CHF2 and CF3, only upper limits were measured. Appearance potentials for halomethyl ions from derivatives have also been measured. From a consideration of these and literature values, best values are proposed for the heats of formation of the radicals and their cations.