Question

Are carbocations sp² hybridized?

Answer 1

Definition of a carbocation:

1. A chemical species containing a positively charged carbon atom.
2. Example: Methyl carbocation$\left({{\mathrm{CH}}_3}^{+}\right)$.
3. The structure of methyl carbocation is given below:

Explanation:

1. Calculation of hybridization for carbocation:

$H=\frac{1}{2}(V+M+A-C)$

where; $\mathrm{H}=$hybridization

$\mathrm{V}=$number of valence electrons on central atom

$\mathrm{M}=$ number of monovalent side atoms

$\mathrm{A}=$charge on anion

$\mathrm{C}=$charge on cation

Thus for methyl carbocation hybridization will be:

$\mathrm{V}=$number of valence electrons on carbon$=4\left(1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^2\right)$

$\mathrm{M}=$ number of monovalent side atoms

$\mathrm{M}=3$ ($4$ hydrogen atoms present)

$\mathrm{A}=$charge on anion$=0$

$\mathrm{C}=$ charge on cation $=+1$

$H=\frac{1}{2}(4+3+0-1)=3$

Hence, carbocation have ${\mathrm{sp}}^2$ hybridization.

2. So, yes, carbocations are sp² hybridized. In carbocations, carbon atom has three substituents bonded to it and all the three bonds are in the same plane, also carbon atom has an empty p-orbital perpendicular to the plane of the molecule. Thus carbocations are sp² hybridized.