Charge-transfer band shifts in iron(III) hexacyanoferrate(II) by electro-intercalated cations via ground state-energy/lattice-energy link.

It is currently important to achieve and understand adjustments of optical properties: "guest cation" induced CT spectral shifts in Prussian Blue are shown to be driven (via its specific effect on the Fe(CN)6 CT-donor entity) by the cation lattice-energy interaction, as inferred from microgravimetry of introduced alkali-metal ions, and from independent solubility correlations for other intercalated cations.