Question

Trimethylamine has a pyramidal structure while trisilylamine has a planar structure

Answer 1

In case of trimethylamine the lone pair of nitrogen is localised and hence nitrogen is sp³hybridized giving it a pyramidal structure. But incase of trisilylamine the lone pair takes part in backbonding and hence gets delocalised and nitrogen is sp² hybridized and the structure becomes planar.

Answer 2

"The structure of trimethylamine is pyramidal shape due to the presence of $\mathrm{p} \pi-\mathrm{p} \pi$ whereas trisilylamine has planar shape due to the presence of $\mathrm{p} \pi-\mathrm{p} \pi$ bonding.

The trimethyl amine molecular formula is $(CH_3)_3)N$and trisilylamine molecular formula is $(SiH_3)_3N$.

The structure of trimethyl amine is pyramidal shape due to the presence of $\mathrm{p} \pi-\mathrm{p} \pi$bonding.

The structure of trisilylamine is planar due to the presence of $\mathrm{p} \pi-\mathrm{p} \pi$bonding.

In the molecule trisilylamine has vacant d-orbitals which are present in their central atom sulphur.

Therefore, the structure of trimethyl amine is pyramidal shape whereas trisilylamine has planar shape."