E-r-pH and E-r-m(KOH) diagrams for nickel at 25 degrees C

Based on the conclusion that no Ni(III) oxo compounds can exist in oxidized nickel oxide electrodes with the total oxidation number 2.0 < z(Ni) < approx. 3.6 and that non-ideal solid solutions with a formal composition (1 -X-2) Ni(OH)(2) . X-2 NiO2 . x H2O Me are involved, E-r-pH and E-r-m(KOH) diagrams at 25 degrees C were calculated and graphically represented using the thermodynamic standard data determined for hypothetical NiO2 . x H2O. The calculations were performed assuming alpha H2O = 1 in the en tire pH range (E-r-pH diagram) and considering the true water activity in KOH sol;lions of various concentrations (E-r-m(KOH) diagram).