wat is carbocation

Carbocation  may be defined as a group of atoms that contains a carbon bearing positive charge containing only six electrons in its valance shell. These ions are formed by heterolytic cleavage in which the leaving group takes along with it the shared pair of electrons.

A carbocation may be formed in a number of ways:

1. By heterolysis of C-X bond in alkyl halides.

(CH₃)₃C-Cl   ----------->      (CH₃)₃C⁺                  +    Cl^-

Tert-Butyl Chloride    Tertiary butyl carbocation

 ii. By protonation of alkene in the acidic medium.

H⁺  +  CH ₂= CH₂  ---------->  CH₃-CH₂⁺

Ethene   Ethyl                    carbocation

The orbital structure of carbocation:

The positively charged carbon atom in carbocation is sp² hybridised. The sp² hybridised orbitals are involved in the formation of sigma bonds with orbitals of other monovalent atoms or groups. The unhybridised orbital has no electrons in it. The three hybridised orbitals lie in a plane with bond angle equal to 120⁰.The unhybridised  orbital is directed perpendicular to the plane. So, a carbocation is a planar structure.

Carbocations can be classified as primary, seconday and tertiary carbocations.