Naphthalene is a polycyclic aromatic hydrocarbon consisting of two fused benzene rings. The resonance structures of naphthalene illustrate how the electrons are delocalized across the molecule. Below are three major resonance structures of naphthalene:
- Resonance Structure 1: In this structure, the double bonds are located between the first and second carbon atoms in one ring and between the third and fourth carbon atoms in the other ring.
- Resonance Structure 2: Here, the double bonds shift one position to the right. Now, the double bond is between the second and third carbon atoms in one ring and between the fourth and fifth in the other ring.
- Resonance Structure 3: In this final structure, the double bonds have shifted again so that they are between the third and fourth carbon atoms in one ring and between the fifth and sixth carbon atoms in the other ring.
These resonance structures show that the electrons are not fixed in one location but rather are distributed over the entire naphthalene molecule, contributing to its stability and unique aromatic characteristics. In reality, the actual structure of naphthalene is a hybrid of these resonance forms, leading to an equally spaced bond length between the carbon atoms.