Question

What is nitrogen inversion?

Answer 1

It's a quantum tunneling effect where the nitrogen atom protons tunnel through a potential energy barrier that allows the molecule to invert its shape. Examples are `"NH"_3`, `"PH"_3`, and `"AsH"_3`.

The potential energy double well can be represented as follows:

This activation energy is around `V_0 ~~ "24.2 kJ/mol"`, so this inversion can happen readily.

For comparison, a typical reaction activation energy is between `"20 kJ/mol"` (very fast) and `"150 kJ/mol"` (fairly slow).