Simplest aromatic hydrocarbon (see aromatic compound ), parent substance of a large class of chemical compounds.
It was discovered in 1825 by 6 H 6 ; August Kekule von Stradonitz in 1865 was the first to propose the correct structure, a six-membered ring of {{link=carbon">carbon atoms, each with one hydrogen atom bonded to it (see bonding ). Although benzene is often represented with alternating single and double bonds between carbon atoms, the electrons in the bonds are shared or delocalized in such a way as to make all carbon-carbon bonds alike. Benzene is a colourless, mobile liquid with a characteristic odour. An excellent solvent, it is also widely used as a starting material for many plastics, dyes, detergents, insecticides, and other industrial chemicals. Benzene is highly toxic, and long exposure may cause leukemia .