Calorimetric and spectroscopic studies of solutions of copper(II) and nickel(II) nitrates in water-carbamide mixtures at 298.15 K

The heat effects of mixing aqueous solutions of copper(II) and nickel(II) nitrates with water-carbamide mixtures were measured on an isothermic-shell calorimeter in the amide concentration region. An increase in the concentration of carbamide strengthened solvation in copper(II) salt solutions to a greater extent. The electronic absorption spectra were recorded at fixed concentrations of the electrolytes to find that the solvation of copper(II) and nickel(II) nitrates in water-carbamide mixtures involved intrasphere and predominantly outer-sphere cation-solvent interactions, respectively.