The title compound, 4C12H9N2 +2C10H5O8C10H4O8 2, contains singly and doubly deprotonated tetracarboxylic acids and the protonated form of 1,10-phenanthroline; the dianion is centrosymmetric. The crystal structure is stabilized by strong intermolecular O—H O and N—H N hydrogen bonds, linking the ions to form a three-dimensional network.
