organic chemistry Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; ...

, the phenylene group () is based on a di-substituted

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, ...

ring (

arylene An arylene or arenediyl is a substituent of an organic compound that is derived from an aromatic hydrocarbon (arene) and is bivalent, such as phenylene. See also *Aromatic hydrocarbon *Aromaticity In chemistry, aromaticity is a chemical pr ...

). For example, poly(''p''-phenylene) is a

polymer A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...

built up from ''para''-phenylene repeating units.p. C-9, Section 11.6, Handbook of Chemistry and Physics, 62nd Edition, 1981-1982, CRC Press The phenylene group has three

structural isomer In chemistry, a structural isomer (or constitutional isomer in the IUPAC nomenclature) of a chemical compound, compound is another compound whose molecule has the same number of atoms of each element, but with logically distinct chemical bond, b ...

s, based on which hydrogens are substituted: ''para''-phenylene, ''meta''-phenylene, and ''ortho''-phenylene.

References

Arenediyl groups {{Aromatic-stub