Molar Volume and Ionic Conductivity in Molten PbBr₂-NaBr and PbBr₂-KBr Systems

Abstract

Molar conductivities of molten PbBr₂-NaBr and PbBr₂-KBr systems were evaluated using the data of molar volume and electrical conductivity which were measured by dilatometry and a conventional a.c. technique, respectively. The molar conductivities of both systems increase with increasing temperature. The molar conductivity isotherm of molten PbBr₂-NaBr system shows a gradual increase with increasing NaBr concentration, but that of molten PbBr₂-KBr system gives little change in spite of an increase of KBr concentration especially in a PbBr₂-rich region. These results suggest some complex formation in the molten salts and predominant complex ion such as PbBr₄²⁻ is expected from the results of Raman spectroscopy and neutron diffraction.