Reactive Intermediates

Carbocations: contain carbon bearing a positive charge. They are sp2 hybridized. Carbocations are electron deficient, so they are strong electrophiles (Lewis acids). Like radicals, they are stabilized by alkyl substituents through (a) the inductive effect, and (b) hyperconjugation. The inductive effect is donation of electron density through the sigma bonds of the molecule. The positively charged carbon atom withdraws some electron density from the alkyl groups bonded to it. Hyperconjugation refers to the weak partial overlap of filled p orbitals with empty ones. Cations are also stabilized by resonance.