Crystal spectra of metal chelates—I

Abstract

From the measurement of absorption spectra of crystals of biguanide complexes of copper chloride, -bromide and -fluoride, it has been concluded that the five fold degenerate d-orbitals of copper ion are split into four levels by the electrostatic field of the four ligand donor atoms in the plane of the molecule. The electronic transitions between these levels give rise to three absorption bands two of which are both x(y) and z polarized, while the other is only x(y) polarized. The vibronic perturbation which makes these forbidden g-g transitions allowed has been assigned. Similar effect has been noticed with nickel complex, but the analysis was not complete as the whole of the spectrum could not be recorded.