[{"from": "human", "value": "Describe this molecule. [C][C][Branch1][#Branch2][C][=Branch1][C][=C][C][=Branch1][C][=O][O-1][C][=Branch1][C][=O][O-1]"}, {"from": "gpt", "value": "The molecule is the dicarboxylate anion of 2-methylene-3-methylsuccinic acid; major species at pH 7.3. It is a conjugate base of a 2-methylene-3-methylsuccinic acid."}]