an aromatic hydrocarbon, or arene, is a hydrocarbon ring compound. it has alternating double and single bonds between carbon atoms forming rings. many of the compounds have a sweet scent, hence the term 'aromatic'. the ring of six carbon atoms in aromatic compounds is known as a benzene ring, after the simplest possible hydrocarbon ring, benzene. aromatic hydrocarbons can be "monocyclic" (mah) or "polycyclic" (pah).