Electrical Conductivities and Molar Volumes in the Binary Systems MnCl2 ‐ LiCl , MnCl2 ‐ NaCl , MnCl2 ‐ KCl , MnCl2 ‐ RbCl , MnCl2 ‐ CsCl

Abstract

The densities and the electrical conductivities of the five binary , have been measured. The molar volumes exhibit increasing positive deviations from additivity, as the size of the alkali metal cation in ACl is increased from , and have a maximum positive deviation at approximately . The molar conductances exhibit an increasing negative deviation from ideality, with a minimum occurring approximately at . The concentration dependence of the molar volumes and of the electrical conductivities in these systems is interpreted in terms of a complex ion model (1) proposed previously for the purpose of interpreting their thermodynamic properties. According to this model the solutions of with alkali chlorides are characterized by the presence of the complex anions. The difference between a “free” chloride anion and a chloride anion bonded within a complex configuration, lies in differences in the strength of the anion‐to‐cation bonds in these two configurations. In this respect, the continuity of the quasilattice structure of a molten salt is not disrupted by the presence of complex species and the latter are not expected to occupy single “lattice” sites within the liquid, as local electrical neutrality is always maintained. Good agreement is obtained between the experimental and the theoretical values for the electrical conductivities and the molar volumes in the systems , , and . The deviations from ideal behavior are small in the systems and . The coefficients for thermal expansion and the activation energies for specific and molar conductances were also calculated from the experimental results and their concentration dependences are also indicative of complex formation.