The structure of benzene can be better explained by the orbital overlap concept,
i. All six carbon atoms in benzene are sp2 hybridized. Two sp2 hybrid orbitals of each carbon atom overlap and form carbon-carbon sigma (σ) bond and the remaining third sp2 hybrid orbital of each carbon overlaps with s orbital of a hydrogen atom to form six C – H sigma bonds.
ii. The unhybridized p orbitals of carbon atoms overlap laterally forming π bonds. There are two possibilities of forming three π bonds by overlap of p orbitals of C1 – C2 , C3 – C4 , C5 – C6 or C2– C3 , C4 – C5 , C6 – C1 , respectively, as shown in the following figure. Both the structures are equally probable.
According to resonance theory, these are two resonance structures of benzene.
