Electrical Conductivity of Molten Cobalt Dibromide + Potassium Bromide Mixtures

Electrical conductivities of CoBr2 and CoBr2 (1) + KBr (2) mixtures in the whole range of compositions were
measured as a function of the temperature by the conductometric method. Parameters of an Arrhenius-type equation,
preexponential factors and activation energies for conduction of molten salts, calculated with the least-squares
method are given. The electrical conductivity of the molten CoBr2, reported here for the first time, shows a high
value of activation energy of (30.90 ± 0.52) kJ·mol-1, decreasing on addition of KBr, probably due to disruption
of a network structure of the pure molten cobalt dibromide. Comparing the conductivity isotherms at 1100 K for
the molten systems CoCl2 (1) + KCl (2) and CoBr2 (1) + KBr (2), one notes that that of the CoCl2 (1) + KCl
(2) system is rather regular, whereas in the CoBr2 (1) + KBr (2) system a significant drop of conductivity is
observed at x1 = 0.333. This last may indicate the formation of the complex ions CoBr42- in the liquid mixture
in the course of melting of the compound K2CoBr4.