Product studies on reactions of recoiling silicon atoms in binary mixtures of phosphine, the silicon precursor, and silane, disilane, and trisilane, respectively, support a mechanism for the product-forming steps involving silylene 81SiH2 as the principal reactive intermediate which gives rise to the observed products. In each case the major product is a next-higher homolog of the starting silane, the expected product of Si-H insertion by 31SiH2. Four other mechanisms are discussed and rejected on the basis of product studies and scavenger experiments. Competition experiments in ternary phosphine-silane-disilane and quaternary phosphine-silane-disilane-nitric oxide mixtures are correlated by a kinetic scheme for the product-determining steps involving a single intermediate. It is suggested that the product-determining steps are the product-forming steps and that the single kinetically important intermediate is 31SiH2. Formation of lower homologs of the major products is explained by the unimolecular dissociation of vibrationally excited silylene insertion products.
|Original language||English (US)|
|Number of pages||14|
|Journal||Journal of Physical Chemistry|
|State||Published - 1972|
ASJC Scopus subject areas
- Physical and Theoretical Chemistry