Carbocations are one of the reaction intermediates formed during several nucleophilic substitutions or elimination reactions. A carbocation is an electron-deficient species with the central carbon atom having six electrons and three bonded atoms. The central carbon in a carbocation is sp2 hybridized with trigonal planar geometry. It has an empty p orbital perpendicular to the plane of the structure that can accept electrons. Thus, carbocations act as strong electrophiles and may react with any nucleophile.
A methyl cation is the simplest form of carbocation, which has three hydrogen atoms attached to the central carbon. Each hydrogen atom can be replaced with an alkyl substituent to generate a primary, secondary or tertiary carbocation.
The stability of the carbocation can be estimated by the inductive effect and hyperconjugation phenomenon that directly depends on the number of alkyl substituents adjacent to the central positive carbon atom. Thus, the carbocation’s stability increases with the increase in the number of alkyl groups.