Lewis Acidity
Covalently saturated silicon complexes like SiBr4, along with tetrahalides of germanium (Ge) and tin (Sn), are Lewis acids. Although silicon tetrahalides obey the octet rule, they add Lewis basic ligands to give adducts with the formula SiBr4L and SiBr4L2 (where L is a Lewis base). The Lewis acidic properties of the tetrahalides tend to increase as follows: SiI4 < SiBr4 < SiCl4 < SiF4. This trend is attributed to the relative electronegativities of the halogens.
The strength of the Si-X bonds decrease in the order: Si-F > Si-Cl > Si-Br > Si-I.
Read more about this topic: Silicon Tetrabromide
Famous quotes containing the word lewis:
“Nearing again the legendary isle
Where sirens sang and mariners were skinned,
We wonder now what was there to beguile
That such stout fellows left their bones behind.”
—Cecil Day Lewis (1904–1972)