C5H6O4

C5H6O4 is the molecular formula for several chemical compounds, the most common being maleic acid and fumaric acid. These are isomers, meaning they have the same molecular formula but different structural arrangements. Both are dicarboxylic acids, containing two carboxyl functional groups. Maleic acid is a cis isomer, while fumaric acid is its trans isomer. This difference in spatial arrangement significantly affects their physical and chemical properties, such as melting point and solubility.

Maleic acid is typically produced industrially by the oxidation of benzene or butane. It is a white crystalline solid that is soluble in water. Maleic acid is used in the production of resins, polymers, and agricultural chemicals. It is also an intermediate in the synthesis of other organic compounds.

Fumaric acid is often found naturally in plants and fungi, such as in the fumitory plant, from which it derives its name. It can also be produced industrially through fermentation processes or chemical synthesis. Fumaric acid is also a white crystalline solid, but it has lower water solubility compared to maleic acid. It is widely used as a food additive, primarily as an acidulant and flavoring agent, and is designated by the E number E297. It also finds applications in the manufacturing of unsaturated polyester resins and as a curing agent for alkyd resins.