Aromatic hydrocarbon A hydrocarbon with a chemistry similar to that of benzene. Aromatic hydrocarbons are either benzenoid or nonbenzenoid. Benzenoid aromatic hydrocarbons contain one or more benzene rings and are by far the more common and the more important commercially. Nonbenzenoid aromatic hydrocarbons have carbon rings that are either smaller or larger than the six-membered benzene ring. Their importance arises mainly from a theoretical interest in understanding those structural features that impart the property of aromaticity.
Benzenoid aromatic hydrocarbons are also called arenes. Benzene itself is the prototypical arene. The properties associated with aromaticity have little to do with aroma, although the aromatic hydrocarbons were first studied in connection with naturally occurring fragrances. Instead, these compounds possess special stability; take part in certain types of reactions; and exhibit persistence of the structural integrity of aromatic rings during chemical reactions, while groups attached to those rings are chemically altered or manipulated.