Bis(hydrazin-1-ium) bis­(μ(2)-pyridazine-3,6-dicarboxyl­ato)bis­(aqua­lithiate) octa­aqua­bis­(μ(3)-pyridazine-3,6-dicarboxyl­ato)tetra­lithium

The unit cell of the title compound, (N(2)H(5))(2)[Li(2)(C(6)H(2)N(2)O(4))(2)(H(2)O)(2)]·[Li(4)(C(6)H(2)N(2)O(4))(2)(H(2)O)(8)], comprises two centrosymmetric complexes, one double negatively charged and one neutral, and two mono-protonated hydrazine cations. The anionic complex molecule is a dimer, built of a pair of symmetry-related pyridazine-3,6-dicarboxyl­ate ligands and a pair of Li(I) ions, each coordinated by two N,O-chelating sites donated by a ligand mol­ecule and an aqua O atom at the apical position. The penta­coordination around the Li(I) ions is partway between a trigonal–bipyramidal and a square-pyramidal arrangement. The two carb­oxy­lic acid groups of the ligand are deprotonated and one carboxyl­ate O atom of each group is not involved in the coordination, and this applies to both the anionic and the neutral complex. The neutral complex molecule is also composed of a pair of Li(I) ions and a pair of ligand mol­ecules related by a centre of symmetry. They form a dimeric core in which the penta­coordination of the Li(I) ions includes two N,O-bonding groups donated by two ligands and an aqua O atom. The penta­coordination is described as partway between a trigonal–bipyramidal and a square-pyramidal arrangement. The coordinated carboxyl­ate group is bidentate–bridging, forming with an Li(H(2)O)(3) unit a neutral tetra­meric mol­ecule. The coordination of the tetra­coordinated Li(I) ion shows a slightly distorted tetra­hedral geometry. An extended system of O—H⋯O and N—H⋯O hydrogen bonds contributes to the stability of the crystal structure.