- a colorless, crystalline, water-soluble solid, C4H4O4, isomeric with fumaric acid, having an astringent, repulsive taste and faint acidulous odor: used in the manufacture of synthetic resins, the dyeing and finishing of textiles, and as a preservative for fats and oils.
- a colourless soluble crystalline substance used to synthesize other compounds. Formula: HOOCCH:CHCOOH
