The Prefix is Otterbox's least expensive iPhone case. The durable silicone, polycarbonate skeleton build of the OtterBox Prefix is thicker than the Commuter and Reflex, but also the least protective. The Prefix is a one-piece case, meaning that it does not snap in place like the Reflex .
carbon is considered tetravalent because it has four valence electrons the valence electrons are in the outermost shell of the atom and allows carbon to form four bonds to other atoms
I understand that SiCl4 is a tetrahedral therefore it has a permanent dipole which makes it non-polar but I dont understand why the bonds are polar and the actual SiCl4 is not.he next is dissymmetry-in other words it can't be symmetrical. Because SiCl4 has a sp3 hybridization and is tetrahedral in shape, it is therefore symetrical and cannot be a polar molecule. Source(s): old chem notes.