Organometallic compounds. VI . Electron impact fragmentation of some mixed and symmetrical tetraalkyltins

The mass spectra of mixed tetraalkyltins are described and analysed. The fragmentation pattern is in agreement with the hypothesis of prefered Sn(IV) and Sn(II) valence states in the tin‐containing fragments. These states are reached by losing an alkyl radical from the next higher unfavourable valence state, or by losing an alkene or alkane molecule from a favourable valence state. The ease of cleavage of a carbon‐tin bond in the molecular ion parallels the stabilization of the leaving alkyl radical by hyperconjugation. The findings are tentatively extrapolated to the general behaviour of tetraalkyl derivatives of group IV organometallics.