Electrical Conductivity of Molten Bi–BiCl3 and Bi–BiBr3 Solutions

Abstract

The electrical conductivities of molten Bi–BiBr3 solutions were measured as a function of temperature over the entire composition range; the conductivities of Bi–BiCl3 solutions were measured from pure salt to 30 mole % metal. In general, these two systems are very similar. Above 400°C, they resemble the Bi–BiI3 system in which conductivity increases monotonically with metal content; but below 300°C in salt-rich solutions, the conductivities of these two systems decrease with increasing metal content. Between 10 and 80 mole % Bi in the Bi–BiBr3 system and between 10–30 mole % Bi in the Bi–BiCl3 system, positive temperature coefficients were found at all temperatures. Above 500°C, the three predominating conductivity mechanisms are believed to be ionic at less than 10% metal, semiconducting between 20% and 60% metal, and metallic above 80% metal.