Infrared Spectra of Metal Chelate Compounds. VII. Normal Coordinate Treatments on 1:2 and 1:3 Oxalato Complexes

Normal coordinate treatments have been made on the square planar 1:2 oxalato complex of Pt(II) and the octahedral 1:3 oxalato complex of Cr(III), and the results were compared with those obtained with simple 1:1 complexes. It was found that coupling between the ligands in the square planar 1:2 complex is small whereas coupling between the ligands in the octahedral 1:3 complex is appreciable. Observed differences of the spectra between 1:1 and 1:2 oxalato complexes of Pt(II) and between 1:1 and 1:3 oxalato complexes of Cr(III) and Co(III) are in good agreement with the results of these calculations.