- a white, crystalline compound, C6H8O2, slightly soluble in water, soluble in many organic solvents: used as a preservative in pharmaceuticals, cosmetics, and food.
- a white crystalline unsaturated carboxylic acid found in berries of the mountain ash and used to inhibit the growth of moulds and as an additive for certain synthetic coatings, as of cheese (E200); 2,4-hexadienoic acid. It exists as cis- and trans- isomers, the latter being the one usually obtained. Formula: CH 3 CH:CHCH:CHCOOH
