cyclohexa135triene

Cyclohexa-1,3,5-triene, commonly known as benzene, is a cyclical organic compound with the chemical formula C6H6. It is a colorless liquid at room temperature and has a distinct sweet odor. Benzene is an aromatic hydrocarbon, meaning it possesses a planar ring structure with delocalized pi electrons that confer unusual stability. This aromaticity is a key feature of its chemical behavior.

The structure of benzene was a significant puzzle in organic chemistry for many years. It was eventually proposed by August Kekulé that benzene exists as a resonance hybrid of two equivalent cyclohexatriene structures, each with alternating single and double bonds. Modern understanding describes the six carbon atoms in the ring as being sp2 hybridized, with each carbon atom forming sigma bonds with two adjacent carbon atoms and one hydrogen atom. The remaining p orbitals on each carbon atom overlap to form a delocalized pi electron system above and below the plane of the ring.

Benzene is a fundamental building block in organic chemistry and is widely used as a precursor to many other chemicals, including plastics, synthetic fibers, and pharmaceuticals. Historically, it was used as a solvent, but its carcinogenic properties have led to significant restrictions on its use in this capacity. Its reactivity is characterized by electrophilic aromatic substitution reactions, where substituents replace hydrogen atoms on the benzene ring, preserving the aromatic system.