5.
Novel mixed valence states have been obtained by the treatment of cobaltous ferrocyanides (Co
+2Fe
II) and ferricyanides (Co
+2Fe
III) in an ozone flow. The CN stretching bands occur at 2085 cm
–1 for Co
+2Fe
II and at 2160 cm
–1 for Co
+2Fe
III. After the ozonization process of Co
+2Fe
II, an intense band approximately at 2125 cm
–1 is detected. This intermediate band must correspond to a mixed valence state of the type: Fe
II–CN–Co
2+–NC–Fe
III Mössbauer spectra recorded in situ during the ozonization of Co
+2Fe
II 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 Mössbauer and infrared spectra of the aged samples of the Co
+2Fe
II after ozonization, a relaxation process to the initial state of the samples is observed but the mixed valence state is stable.
相似文献