Silyl radicals silylene anion radical

The first step in the polymerization is the electron transfer from sodium to dichlorosilane and the formation of the corresponding radical anion. The latter upon elimination of the chloride anion is transformed to the silyl radical. To fit the chain growth mechanism, the reactivities of the macromolecular radicals must be higher than the reactivities of the monomeric radicals. The latter after electron transfer and elimination of chloride anion could be transformed to the reactive silylenes. Thus, in principle, two or more mechanisms of chain growth are possible ... 

Organosilicon chemistry has expanded its scope considerably in the last two decades. One of the most remarkable achievements is the progress which was made in the elucidation of the mechanisms in silicon chemistry, which now become comparable to those in carbon chemistry. The behavior of reactive intermediates such as silylenes, silyl radicals and silyl anions are well explored, although the chemistry of silyl cations is still controversial. Doubly-bonded silicon species are now well understood " but triply-bonded silicon is still elusive. 

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