The molecule is a dicarboxylic acid dianion obtained by deprotonation of the carboxy groups of 2-hydroxyhepta-2,4-dienedioic acid; major species at pH 7.3. It is a conjugate base of a 2-hydroxyhepta-2,4-dienedioic acid. It is a tautomer of a 2-oxohept-4-ene-1,7-dioate.
(3E,5Z)-7-hydroxy-6-oxido-7-oxohepta-3,5-dienoate