Site-transfer conductivity in solid iron hexacyanoferrates by dielectric relaxometry, voltammetry and spectroscopy. Prussian Blue, congeners and mixtures

Charge-transfer processes in iron(III) hexacyanoferrate(II), i.e. Prussian Blue (PB), have been studied by conductimetry, dielectric relaxometry (DR) and spectrophotometry. In dry PB the predominant process is sitewise electron transfer, from agreement in inferred electron-transfer frequencies, v. When wet or admixed with salts allowing ionic conduction, the latter dominates, with evident accompanying redox processes at the electrodes. The reduced and oxidised congeners of PB have higher conductivities arising from more complex mechanisms. The prediction of the d.c. conductivity of PB from optical charge-transfer parameters is reasonably successful.