In trisilicylamine `(SiH_(3))_(3)N`, the ione elec tron pair on the nitrogen atom is involved in `p pi-p pi` bondoing with the vacant 3d orbitals on silicon atom. As a result, it is not as easily available to the attacking Lewis acid as in case of trimethylamine `(ch_(3))_(3)N`. whre the electron pair is rather free.
