Aromaticity of Benzene
Benzene is a cyclic system of 6 π electrons delocalized. It consists of 6 carbons with sp2 hybridization whose p orbitals overlap, forming a cloud that allows the delocalization of the p electrons and confers great stability to benzene.
Hückel's Rules
This stabilization energy, called aromaticity, is present in other molecules that we can identify by following Hückel's rules:
Rule 1.- An aromatic system must be cyclic and planar (without sp3 carbons in the cycle)
Rule 2.- There is cyclic conjugation of the double bonds.
Rule 3.- The number of p electrons in the aromatic system complies with the formula 4n + 2, where n = 0, 1, 2, 3 ......