Note the bonding order of 4 in the lattice and the 6 member rings formed by it. Reminiscent of hexose sugars which also have bonding order of +/-4 and form comfortable 6 member rings (as well as five member rings which are somewhat strained). Si is of a same feather as C, giving it the same connectivity. (Thats Si for Silicon and C for Carbon) There's actually a StarTrek episode that proposes the idea of Silicon based life, which is based off of this exact idea of identical connectivity shared by these main group elements.
