SiH4

The elements of Period 2 (Li—F) cannot have a co valency greater than 4, because not more than four orbitals are available for bonding. In Period 3 (Na—Cl) similar behaviour would be expected, and indeed the molecule SiH4 is tetrahedral like that of CH4, and PH3 is like NH3 with a lone pair occupying one tetrahedral position. 

How do the following hydrides react with water NaH, CH4, SiH4 and HI Comment on these reactions in terms of the nature of the chemical bonds in these compounds. Suggest reasons for the increase in acidity in the series PH3, HjS, HCl. How would you seek to establish this order experimentally ... 

All of the atomic species which may be produced by photon decomposition are present in plasma as well as the ionized states. The number of possible reactions is therefore also increased. As an example, die plasma decomposition of silane, SiH4, leads to the formation of the species, SiH3, SiHa, H, SiH, SiH3+ and H2+. Recombination reactions may occur between the ionized states and electrons to produce dissociated molecules either direcdy, or tlrrough the intermediate formation of excited state molecules. 

It therefore appears that other hydrocarbons than medrane take part, but to a lesser extent. The other species which were considered in this calculation were SiCl, SiH4, CH3CI, SiHs, H, Si, Sia, Cl and CI2, all of which are gaseous at this temperature. It is difficult to predict before dris calculation what will be the major species, and attempts to limit die number of compounds which are included is to some extent subjective, but this can be conected by using the graphical method as a preliminaty. 

The stmcture used as the basis of the nomenclature is silane SiH4 corresponding to methane CH4. Silicon hydrides of the type SiH3(SiH2) SiH ... 

Silicon hydride (Silane) (SiH4) Explosive Rapid... 

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