Phase Diagram and Electrical Conductivity of CeBr3-KBr

Abstract

This paper continues our research program on lanthanide halide-alkali metal halide systems. Differ-ential scanning calorimetry (DSC) was used to investigate the phase equilibria of the CeBr3-KBr sys-tem. This system is characterized by the two congruently melting compounds K3CeBr6 and K2CeBr5 and the three eutectics located at the CeBr3mole fractions 0.193 (837 K), 0.295 (855 K) and 0.555 (766 K). K3CeBr6 forms at 775 K and melts congruently at 879 K with the related enthalpies 54.5 and 41.7 kJ mol-1, respectively. K2CeBr5 melts congruently at 874 K with the enthalpy 82.4 kJ mol-1. The electrical conductivity was measured of all CeBr3-KBr mixtures and of the pure components down to temperatures below solidification. The experimental determinations were conducted over the entire composition range in steps of about 10 mol%. The specific electrical conductivity decrease with increasing CeBr3 concentration, with significantly larger conductivity changes in the potassium bromide-rich region. The results are discussed in terms of possible complex formation. © 2007, Verlag der Zeitschrift für Naturforschung. All rights reserved.