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
A few molecules have a tetrahedral geometry with no central atom. An inorganic example is tetraphosphorus (P 4) which has four phosphorus atoms at the vertices of a tetrahedron and each bonded to the other three.mmonia (NH 3) can be classified as tetrahedral, if one considers the lone pair as a ligand as in the language of VSEPR theory. The H-N-H angles are 107Â°, being contracted from 109.4Â°, a difference attributed to the influence of the lone pair.