Abstract The exchange of oxygen functional groups ( OR, O and OCOMe) and sulphur functional groups ( SR, S) between R 3 M (M= Si, Ge, Sn and Pb) and R 2 M (M= Si, Sn) shows, in general, the heavier Group IV element to prefer sulphur. This supports the phenomenological rationalisation that the softness of the organometallic residue increase with the atomic weight of M, though germanium probably resembles silicon in its ...
