LUMINESCENCE STUDY OF THE THERMAL-DECOMPOSITION OF EUROPIUM TRICHLORIDE HEXAHYDRATE, EUCL3.6H2O

We have studied the thermal decomposition of EuCl3.6H2O using in situ measurements of the Eu3+ ion luminescence spectrum. The luminescence s pectrum proved to be extremely sensitive to structural and composition al changes undergone by the title compound during the decomposition pr ocess. There appeared to be no change in the oxidation state of the eu ropium throughout the decomposition process. Four differently hydrated species of EuCl3.nH2O(n=6,3,2, or 1) were identified via luminescence spectroscopy. We also observed another intermediate compound formed f rom the monohydrate prior to the final product EuOCl. Our analysis of this intermediate's spectrum indicates a single Eu3+ ion site, which i s consistent with a formulation of Eu(OH)Cl2 rather than a mixed EuOCl .2EuCl3 product, both of which have been postulated by others on the b asis of their thermogravimetric measurements.