citral

a yellow volatile liquid with a lemon-like odour, found in oils of lemon grass, orange, and lemon and used in perfumery
 * Citral** is a mixture of, a pair of terpenoids with the molecular formula C10H16O. The two compounds are double bond isomers. The E-isomer is known as geranial or citral A. The Z-isomer is known as neural or citral B. This chemical has a strong lemon odor. Citral is an aroma compound used in perfumery for its citrus effect. Citral is also used as a flavor and for fortifying lemon oil.