Crystal structures Prussian blue solids

As shown in Fig. 2.5, the cyclic voltammograms for Prussian blue attached to paraffin-impregnated graphite electrodes (PIGEs) in contact with aqueous electrolytes exhibit two well-defined one-electron couples. Prussian blue crystals possess a cubic structure, with carbon-coordinated Fe + ions and nitrogen-coordinated Fe + ions, in which potassium ions, and eventually some Fe + ions, are placed in the holes of the cubes as interstitial ions. The redox couple at more positive potentials can be described as a solid-state process involving the oxidation of Fe + ions. Charge conservation requires the parallel expulsion of K+ ions [77] ... 

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