Cyclic hydrocarbon with the molecular formula C6H6. Most simple variant of the aromatic hydrocarbons characterized by the presence of a planary structure of one or more cyclic systems with conjugated (connected) double bonds. Formerly used as a solvent, benzene has been replaced in this application after the confirmation of its carcinogenic potential by toluene (methylbenzene) and xylene (isomers of dimethylbenzenes).