Aromatic compounds containing one or more distinct benzene rings as part of their structural framewo — Hydrocarbons Chemistry Question

💡 Solution & Explanation

Naphthalene consists of two fused benzene rings. Anthracene consists of three linearly fused benzene rings. Biphenyl consists of two directly connected (isolated) benzene rings. All of these possess strict benzenoid structures. In contrast, Azulene ($C_{10}H_8$) is an aromatic isomer of naphthalene consisting of a fused 5-membered ring and 7-membered ring, lacking a distinct 6-membered benzenoid core, classifying it as a non-benzenoid aromatic hydrocarbon.