| Ionone
One of two cyclic terpene ketones with an odor of violets or cedar wood, the a and ß varieties of which differ in the location of the double bond in the ring: provitamins A and vitamin A have ionone configuration in the ring portion; a-carotene contains one a- and one ß-ionone moieties, ß-carotene contains two ß-ionone moieties, and ?-carotene contains one ß-ionone moiety. | |