The effect of temperature on the electronic spectra of octahedral iron(II) complexes

Abstract

Spectral changes in iron(11) complexes caused by temperature changes have been examined. When the iron(11) ion is surrounded by six equivalent ligands (FeC1₂, FeBr₂, FeI₂, FeSiF₆,6H₂O) the band separation that arises from the splitting of the ⁵E_g level decreases on cooling. The variation is proportional to the magnitude of the band separation. In complexes with tetragonal distortion (FeCl₂,2H₂0, FeCl₂,- 2CH₃OH,FeCl₂,4pyridine, FeCl₂,2pyridine, FeCl₂,4isoquinoline, FeBr₂,4isoquinoline) the variation in band separation with change in temperature is smaller and is inversely related to the magnitude of the band separation.