[Di-aqua-sesqui(nitrato-κO)hemi(perchlorato-κO)copper(II)]-μ-{bis-[5-methyl-3-(pyridin-2-yl)-1H-pyrazol-4-yl] selenide}-[tri-aqua-(perchlorato-κO)copper(II)] nitrate monohydrate.

In the binuclear title complex, [Cu2(ClO4)1.5(NO3)1.5(C18H16N6Se)(H2O)5]NO3·H2O, both Cu(II) ions are hexa-coordinated by O and N atoms, thus forming axially elongated CuO4N2 octa-hedra. The equatorial plane of each octa-hedron is formed by one chelating pyrazole-pyridine fragment of the organic ligand and two water mol-ecules. The axial positions in one octa-hedron are occupied by a water mol-ecule and a monodentately coordinated perchlorate anion, while those in the other are occupied by a nitrate anion and a disordered perchlorate/nitrate anion with equal site occupancy. The pyrazole-pyridine units of the organic selenide are trans-oriented to each other with a C-Se-C angle of 96.01 (14)°. In the crystal, uncoordinated nitrate anions and the coordinating water mol-ecules are involved in O-H⋯O and N-H⋯O hydrogen bonds, forming a bridge between the pyrazole group and the coordinating water mol-ecules. Further O-H⋯O hydrogen bonds between the complex mol-ecules and a π-π stacking inter-action with a centroid-centroid distance of 3.834 (4) Å are also observed.