TEMPERATURE COEFFICIENTS OF HALF-WAVE POTENTIALS AND ENTROPIES OF TRANSFER OF CATIONS IN APROTIC-SOLVENTS .2.

Temperature coefficients for the polarographic reductions of Li+, Na+, K+, Rb+, Cs+, Tl+, Cu+, Cu2+, Zn2+, Cd2+, Ba2+, Pb2+ bis(biphenyl) chromium(I) tetraphenylborate, ferrocene and perylene have been derived from measurements vs. the Ag/Ag+ (0.01 mol dm-3) electrodes kept at 25-degrees-C in 0.1 mol dm-3 solutions of tetrabutylammonium perchlorate in acetonitrile, N-methyl-2-pyrrolidone, N-methyl-2-thiopyrrolidone, pyridine and N,N-dimethylthioformamide. Data for Ag+ were obtained from potentiometric measurements. Entropies for the abovementioned redox couples and for Ag+ were calculated for reversible electrode reactions on the basis of the assumption of a negligible thermal diffusion potential. This assumption was also employed to calculate single-ion entropies of transfer from acetonitrile into N-methyl-2-pyrrolidone, N-methyl-2-thiopyrrolidone, pyridine and N,N-dimethylthioformamide.