The first metal complex with the hydrazine dicarboxylate dianion: Na2(O2CNHNHCO2)(H2O)3

The title compound is the first complex of a metal ion with the hydrazinedicarboxylate dianion. One of the sodium cations is coordinated by two N,O-bidenate and two O-monodentate ligands to result in distorted trans-NaN2O4 octahedra. Crystal data: Na2(O2CNHNHCO2) · 3H2O, Mr = 218.08, triclinic, image (No. 2), a = 5.5123 (2) Å, b = 8.7311 (3) Å, c = 8.8117 (3) Å, α = 107.005 (2)°, β = 99.431 (2)°, γ = 101.552 (2)°, V = 385.98 (2) Å3, Z = 2, R(F) = 0.027, wR(F2) = 0.092.