Infrared characterization of turbostratic α- and well crystallized α*-cobalted nickel hydroxides

Abstract

Substitution of at least 20% of trivalent cobalt for nickel leads to α- and α*-nickel hydroxides which are stable in KOH. The compensation of the excess of positive charge results from the insertion of anions (CO 3 2− or SO 4 2−) in the van der Waals gap. The IR study shows that these anions are in D 3 h and T d symmetries, respectively, while the adsorbed ones are linked to the transition elements ( C 2 v and C 3 v symmetries, respectively). This study also confirms the stability of α* Co 3+ - and α Co 3+ -hydroxides in concentrated KOH solution, and the instability of α Co 2+ ones which leads to the formation of β Co 3+ - hydroxides.