Thermal diffusion of lanthanide chlorides

TLDR: In this paper, the molar entropy of rare earth chlorides at 0.001, 0.01 and 0.1N were measured by the potentiometric method using the silver, silver chloride thermocell at a mean temperature of 25°C.

Abstract: The molar entropy (or heat) of transport of aqueous rare earth chlorides at 0.001, 0.01 and 0.1N have been measured by the potentiometric method using the silver, silver chloride thermocell at a mean temperature of 25°C. Our results indicate that the entropy of transport of rare earth chlorides exhibits a two-series, step function type of dependence on ionic radii. Although this is not the usual S-shaped dependence on ionic radii observed in many thermodynamic and transport properties, the Soret data do seem to show that hydration of the heavier rare earth ions may be rather different from the lighter rare earth ions. The concentration dependence of the entropy of transport have also been investigated for LaCl3, SmCl3, and YbCl3. In all cases the experimental limiting slopes agree well with that predicted by theory based on the electrostatic model.