A benzene ring is a simple aromatic ring composed of six carbon atoms forming a six membered ring, with each carbon atom connected to a functional group. All six functional groups of benzene are hydrogen atoms.

However, experiments have shown that benzene cannot fade bromine water or acidic KMnO4, indicating the absence of carbon carbon double bonds in benzene. Research has shown that the carbon atoms on the main chain of the benzene ring are not arranged by the previously recognized single and double bonds (proposed by Kekuler), and the bonds between each two carbon atoms are the same, connected by a bond (large π bond) that is neither a double bond nor a single bond.