Pressure Effect on the Absorption Spectra of Iron Compounds

Abstract

Abstract The effect of pressures up to 50 kbar has been measured on the absorption spectra in five ferric compounds, two ferrous compounds, and one mixed valence compound. In six compounds, but not in basic ferric acetate and soluble prussian blue, we observed pressure-induced bands which were assigned to the d-d transition of the converted Fe(II) for the ferric compounds and to the spin-forbidden d-d transition for the ferrous compounds. The absorption spectra for single crystals of potassium ferri- and ferrocyanide were studied at hydrostatic pressures up to 5 kbar. The band-peak intensity decreased with an increase in the pressure in both cases. The charge-transfer band from Fe(II) to Fe(III) of soluble prussian blue showed a blue shift (69 cm−1/kb) at hydrostatic pressures up to 7.2 kbar.