The 70 eV electron-impact low resolution spectra of Me3SiPPh2, (Me3Si)
3SiPPh2, and (Me3Si)2(Me)SiP(Me)(Ph) were investigated. The migration
of two phenyl groups from phosphorous to a silicon site was observed a
nd the unimolecular mass-analysed ion kinetic energy spectra indicated
that the migration occurred in [M - CH3]+ ions rather than in M+. ion
s. The benzene eliminations from the M+. and [M-CH3]+ ions of Me3SiPPh
2 were observed not in the EI spectrum, but in their MIKE spectra.