Electron impact studies on some organochlorogermanes: Mass spectra and bond dissociation energies

The mass spectra of the methylchlorogermanes and the (chloromethyl)-trichlorogermanes are described and analysed. It is shown by consideration of the ionisation and appearance potentials that the surprisingly high abundance of (M---Cl)⁺ ions in the spectrum of Cl₃GeCH₃ is due to a large decrease of the Ge---Cl bond strength in the molecular ions of methylchlorogermanes with increase in the number of Cl atoms on Ge. Calculated bond energies indicate that this phenomenon reflects Ge---Cl bond energy differences in the neutral molecules.