Select the correct statement(s) with respect to the $p\pi -d\pi$ dative bond.

The $\mathrm{Si}-\mathrm{O}-\mathrm{Si}$ angle is 180$°$ for ${\left({\mathrm{Ph}}_3\mathrm{Si}\right)}_2\mathrm{O}$  

Trisilyl phosphine  ${\left({\mathrm{H}}_3\mathrm{Si}\right)}_3\mathrm{P}$ is planar

Silicon forms acids such as ${\left({\mathrm{CH}}_3\right)}_3\mathrm{SiOH}$ are stronger protonic acids then their carbon analogs.

${\mathrm{ClO}}_4^{-}$ does not polymerise at all.