SMILES: C1=C(C=C(OC1=O)C(=O)[O-])C(=O)[O-]
Description: The molecule is a dicarboxylic acid dianion obtained via deprotonation of both carboxy groups of 2-oxo-2H-pyran-4,6-dicarboxylic acid; major species at pH 7.3. It is a conjugate base of a 2-oxo-2H-pyran-4,6-dicarboxylic acid.