Study of Complex Formation of the Lanthanides by Means of Fluorescence Spectroscopy

Abstract

The absence of the covalent interaction between the rare earth ions and the ligands usually leads to no band shift in the electron absorption spectra due to complexation. Only small variation of the peak intensities is obtained, even at high concentration of the central ion. The determination of complex formation constants from such intensity difference is therefore very difficult, or even impossible for aqueous rare earth systems having low solubility products (e.g. fluoride, hydroxide, oxalate, carbonate). A concentration of not more than 10⁻⁵ − 10⁻⁶ M of the central ion has to be used to obtain the complex formation function of these systems.