Moessbauer and infrared spectroscopy studies of novel mixed valence states in cobaltous ferrocyanides and ferricyanides

Novel mixed valence states have been obtained by the treatment of cobaltous ferrocyanides (Co+2FeII) and ferricyanides (Co+2FeIII) in an ozone flow. The CN stretching bands occur at 2085 cm-1 for Co+2FeII and at 2160 cm-1 for Co+2FeIII. After the ozonization process of Co+2FeII, an intense band approximately at 2125 cm-1 is detected. This intermediate band must correspond to a mixed valence state of the type: FeII-CN-Co2+-NC-FeIII Moessbauer spectra recorded 'in situ' during the ozonization of Co+2FeII show the presence of two components: A doublet with isomer shift and quadrupole splitting values close to the cobalti ferricyanide and a very broad line for the mixed valence state. From the Moessbauer and infrared spectra of the aged samples of the Co+2FeII after ozonization, a relaxation process to the initial state of the samples is observed but the mixed valence state is stable. (orig.)