The molecule is an oxo monocarboxylic acid anion that is the conjugate base of all-trans-4-oxoretinoic acid, obtained by deprotonation of the carboxy group; major species at pH 7.3.
(2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethyl-3-oxocyclohexen-1-yl)nona-2,4,6,8-tetraenoate