found that using a value of kf greater than 1 x 10 7 M -1 s -1 yielded the best fit to the experimental voltammograms, as shown in Figure . As clearly evident by inspection of Figure , the 8-step mechanism shown in Scheme 4, with the rate constants listed in Table precisely captures the CV behavior of solutions containing 0.54 mM Ru(NH3)6 2+ , 1.0 mM S2O8 2-, and 0 to 220 mM C2O4 2-.