ABSTRACT
The common oxidation states of iron in aqueous solutions are Fe (II) and Fe (III). In alkaline solutions, the unstable oxidation states Fe (IV) and Fe (VI) are known to exist. Fe (V) salts and complexes containing Fe (I), Fe (O), Fe (-I), and Fe (-II) have been prepared. In principle, it is also possible to derive the standard potential from equilibrium potentials obtained from kinetic measurements. T. Hurlen extrapolated Tafel lines of iron dissolution and deposition measured in acidified solutions of iron (II) sulfate and chloride to their intersection. For a large number of electrochemical reactions in the systems iron-water and iron-water-sulfur, R. H. Biernat and R. G. Robins published tables of calculated standard potentials at temperatures of 298 K = T = 573 K. Conditional standard potentials of the iron(II/III)-oxalate electrode reactions in solutions containing a relatively high concentration of sodium oxalate in the supporting electrolyte.
