Why does R३P = O exit but R३N = O does not (R = alkyl group)?
Explanation D-orbital starts from the 3rd period of periodic table. As Nitrogen comes in 2nd period and doesn’t contain any d-orbital hence it has a maximum covalency of 3 and cannot share any electrons further. Although Phosphorus, being in 3rd period contains an empty 3 d-orbital and its p-orbital electrons are ready to share their electrons pair, and hence 2 electrons excites from p to d orbital and its covalency changes from 3 to 5. This makes the phosphorus capable of forming 5 bonds in sharing but not nitrogen.
