TEMPERATURE COEFFICIENTS OF CU/CU2+ AND HG/HG2+ ELECTRODE-POTENTIALS AND GIBBS ENERGIES, ENTROPIES AND ENTHALPIES OF TRANSFER FOR CU2+ AND HG2+

Temperature coefficients of the electrode potentials for the Cu\Cu2+ and Hg\Hg2+ couples have been derived from potentiometric measurements at different temperatures vs. the Ag\Ag+ (0.01 mol dm-3, 25-degrees-C) reference electrode in water, acetonitrile, benzonitrile, propylene carbonate, ethane-1,2-diol (ethylne glycol), acetone, N-methylacetamide, N,N-dimethylformamide, N,N-dimethylacetamide, methanol, ethanol, propan-1-ol, nitro-methane, sulfolane (tetrahydrothiophene-1,1-dioxide), dimethyl sulfoxide and N-methyl-2-pyrrolidone. The temperature coefficients for the Cu\Cu2+ system in acetonitrile and benzonitrile were calculated from the temperature coefficients of the Cu\Cu+ and Cu+\Cu2+ couples. Single-ion entropies of transfer of Cu2+ and Hg2+ from N,N-dimethylformamide as reference solvent were calculated from the temperature coefficients of the Cu\Cu2+ and Hg\Hg2+ electrode potentials. Gibbs energies of transfer were derived from the electrode potentials of the Cu\Cu2+ and Hg\Hg2+ couples measured at 25-degrees-C against the Ag\Ag+ (0.01 mol dm-3, acetonitrile) reference electrode. Transfer enthalpies were calculated from the Gibbs energies and the entropies of transfer.