Mössbauer Study of Soluble Prussian Blue, Insoluble Prussian Blue, and Turnbull's Blue

The electronic structures of soluble Prussian blue, insoluble Prussian blue, and Turnbull's blue were investigated by the Mössbauer effect of 57Fe. The results below their Curie temperatures of 5.5° ± 0.5°K show that all of them are ferric ferrocyanide: one kind of irons is Fe3 + with high spin and the other is Fe(II) with low spin. It is concluded that Prussian blue and Turnbull's blue have the same electronic structure. The results of a paramagnetic resonance absorption observed at room temperature also support the conclusions obtained by the Mössbauer study.