Electronic and vibrational spectra of ferricyanide ions doped in NaCl and KCl crystals

Ten absorption bands are observed in the electronic spectra of NaCl and KCl crystals doped with Fe(CN) 6 3- ions in the range 50000-20000 cm -1 . Six of these bands are assigned to the ligand to metal charge transfer transitions (t 1u 6 t 2g 5 to t 1u 5 t 2g 6 and t 1u 5 t 2g 5 e g 1 and a 1g 2 t 2g 5 to a 1g 1 t 2g 6 ). The positions of these bands agree with those calculated using Dq=1944 cm -1 , B=623 cm -1 and C=3270 cm -1 for d 6 configuration. The remaining four bands are assigned to crystal field transitions for d 5 configuration and agree with the calculated peak positions for Dq=3450 cm -1 , B=700 cm -1 and C=2400 cm -1 . Vibration spectrum in the (C identical to N) stretch region shows that the Fe(CN) 6 3- ion is present predominantly in the C s site symmetry.