Hemipiperazinediium bis­(pyridine-2,6-dicarboxyl­ato-κ(3) O,N,O′)gallate(III) pyridine-2,6-dicarboxylic acid dihydrate

The asymmetric unit of the title compound, (C(4)H(12)N(2))(0.5)[Ga(pydc)(2)]·pydcH(2)·2H(2)O, where pydcH(2) is pyridine-2,6-dicarboxylic acid, C(7)H(5)NO(4), contains one half of a centrosymmetric piperazinediium dication, one anion, one uncoord­inated pydcH(2) mol­ecule and two uncoordinated water mol­ecules, one of which is disordered over two sites in a 1:1 ratio. In the anion, the Ga(III) ion is coordinated by four O atoms [Ga—O = 1.9706 (16)–2.0494 (15) Å] and two N atoms [Ga—N = 1.9660 (18) and 1.9709 (17) Å] from two pydc ligands in a distorted octa­hedral geometry. The crystal structure exhibits inter­molecular O—H⋯O, N—H⋯O and O—H⋯N hydrogen bonds and π–π inter­actions [centroid–centroid distances of 3.5359 (13) and 3.6550 (14) Å].