Above is the molecular structure of benzene, the benzene ring formula, and the systematic name.

Image: Kikule benzene formulas showing the resonance structures characterized by the shifting locations of the double bonds.

  • Benzene is an aromatic hydrocarbon, a six carbon ring made of only hydrogen an carbon atoms
  • The benzene ring formula is C6H6.
  • It is a cyclic compound on its own and may be attached other molecules forming a class of compounds called aromatics.
  • The molecular structure of benzene is often drawn with alternating single and double bonds in two resonance structures. Neither of these structures actually exist in the real world as one or the other. Both resonance structures exist simultaneously as a hybrid.
  • Each C-C bond in the ring is the same length and has a bond order of 1.5. This is because of pi bonding. Pi electrons have the ability in the benzene ring to become delocalized, meaning they are able to move freely from carbon to carbon around the ring. 
  • The shorthand image of the molecular structure of benzene is drawn with a circle to reflect the molecule's hybrid character and free movement of the pi electrons.Since single bonds are longer than double bonds, the equal bond length of all 6 C-C bonds that is observed is proof of the electron sharing--the bond order of a C-C Benzene Ring bond is 1.5.

The Benzene Ring: C6H6

The structure of benzene is based on 120 degree bond angles surrounding each carbon. The C-H bond length is approximately 109pm while each C-C bond is about 139pm.

Exposure and hazards of Benzene

Benzene is a carcinogen at high concentrations or chronically consumed at low concentrations. Exposure to benzene arises through cigarette smoke and automobile exhaust as it is a component of gasoline and other petroleum products. Industrial uses pose a threat for those with hands on interaction or close contact with solvents, paints, and glues. Inhalation is a common means of accidental exposure due to the low boiling point.

Naming Benzene Rings

Benzene ring nomenclature:-ortho, -meta, -para

Examples: o-dibromobenzene, m-dichlorobenzene, p-iodobenzene. In the image above, substitute the R groups with the respective halogens to understand the benzene ring nomenclature and the structures of these compounds.

Common Aromatic Compounds


TNT - Trinitrotoluene - explosive

Benzoyl Peroxide - acne treatment

Aspirin - Acetylsalicylic acid - pain reliever

Tylenol - Paracetamol - Pain reliever

Styrene  - Used in plastics and resins

Methamphetamine - Narcotic

DNA/RNA Nucleotides:

  • Adenine
  • Guanine
  • Thymine
  • Cytosine
  • Uracil

Four of the 20 amino acids:

  • Histidine
  • Tyrosine
  • Tryptophan
  • Phenylalanine