From: someone@microsoft.com   
      
   [snippage]   
   >> > why does silicon tetrachloride (SiCl4) spontaneously decompose   
   >> > in water and carbon tetrachloride (CCl4) does not?   
   >> >   
   [snippage]   
   >> Because Si has larger area as compared to carbon so water   
   >> molecules can attack as the available free space is more as   
   >> compared to C.   
   [snippage]   
      
   Reactivity is facilitated by enthalpy or Gibbs free energy.   
      
   SiCi4 + 2H2O -> SiO2 + 4HCl  + energy   
      
   H2O + CCl4 don't react because they are not miscible and intimate mixing is   
   required for reaction.   
      
   However, in a supercritical mixture (intimate mixing), H2O + CCl4 might   
   react to products CO2 + 4HCl + heat, but a nickel or rhenium catalysts might   
   be required.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)