Note 542 — Chapter XIV · OXIDATION AND REDUCTION REACTIONS. I

The fact that this equilibrium relation has been proved to hold for the action Fe2+ ⇄ Fe3+ and that it must be taken into account in all oxidation-reduction reactions involving these ions, in no wise excludes the possibility that other equilibrium relations can also exist between ferrous and ferric compounds. For instance, ferrous hydroxide Fe(OH)2 may well have a characteristic tendency of its own to assume a further positive charge (lose an electron) according to Fe(OH)2 ⇄ Fe(OH)2+, the potential of which action may, under given conditions, be a main determining factor in the course of an action, e.g. in alkaline mixtures. It is not impossible, even, that we also must consider negative ions FeO22− and their tendency to be oxidized. Evidence would suggest that ferrous hydroxide, or its negative ion FeO22−, may have, indeed, a very great tendency to be oxidized, possibly much greater than the tendency of Fe2+ to form Fe3+. (Cf. Manchot, Z. anorg. Chem., 27, 419 (1901), and McCoy and Bunzel, J. Am. Chem. Soc., 31, 370 (1909)). Closer investigations of these relations, from a quantitative viewpoint, would probably determine this question and bring exceedingly important relations to light.