C8H6O4n

C8H6O4n is a general chemical notation used to describe a polymer that contains repeating units with the formula C8H6O4, where n denotes the degree of polymerization (the number of repeating units in the chain). The base unit C8H6O4 corresponds to several aromatic dicarboxylic acids, most notably phthalic, isophthalic, and terephthalic acids. These isomers share the same empirical formula but differ in the positions of the carboxyl groups on the benzene ring, which influences polymer structure and properties.

In polymer chemistry, (C8H6O4)n typically implies a polyester or related polymer formed from a diacid derivative with a diol or other bifunctional co-monomer. The exact linkage (for example ester bonds in polyesters) and the choice of co-monomers determine the material’s thermal behavior, crystallinity, mechanical strength, and solubility. A well-known example in this family is polyethylene terephthalate (PET), whose repeating unit is not (C8H6O4)n itself but a related unit derived from terephthalic acid and ethylene glycol; PET has the simplified representation (C10H8O4)n.

Properties of polymers described by this formula family tend to include high thermal stability, aromatic content, and limited water solubility, with performance highly dependent on chain length (n) and the nature of the co-monomers. The underlying monomer, terephthalic/isophthalic/phthalic acid, is industrially important as a precursor to various polyesters and related plastics, and the (C8H6O4)n notation is used mainly for theoretical or shorthand discussions of polymer composition.

Safety and handling follow standard practices for aromatic carboxylic acids and their polymer products.