Question

Nicotine is an addictive substance found in tobacco. Identify the hybridization state and geometry of each of the nitrogen atoms in nicotine:

Answer 1

The structure of nicotine is as follows:

In the aromatic ring, nitrogen atom has two bonds and one lone pair therefore, hybridization will be $sp^{2}$. In five-membered ring , nitrogen has two bonds and 1 lone pair therefore, hybridization will be $sp^{3}$.

Therefore, hybridization state of $N^{1}$ and $N^{2}$ (as in the attached structure) is $sp^{2}$ and $sp^{3}$ respectively.

Now, according to VESPR theory for $sp^{2}$ hybridization with one lone pair the geometry is bent and for $sp^{3}$ hybridization with one lone pair the geometry is pyramidal.

Therefore, geometry of $N^{1}$ and $N^{2}$ (as in the attached structure) is bent and pyramidal respectively.