The spectra of some tetrahedral halide complexes of transition metal ions

Abstract

The solution spectra of tetraethyl ammonium salts of some complex halides of divalent iron, cobalt and nickel over the range 1000–20 000 cm-1 have been obtained. The positions of the various absorption bands can be correlated with transitions within the 3d shell of the metal ion but the relative intensities reveal the inadequacy of the crystal field model as a description of these compounds. The nickel halides are much the most interesting in that not only do they fail to show an expected Jahn-Teller distortion but they provide a clear indication that the contribution to the intensities from the 4p orbitals on the central ion is small.