THERMODYNAMICS OF CHROMIUM(II) AND CHROMIUM(III) SOLUTIONS IN THE FUSED ELITECTICS, LICL-KCL AND LICL-KCL-BACL2

Over the temperature range 370-550-degrees-C the thermodynamic properties of solution of CrCl2 and CrCl3 in fused eutectics LiCl-KCl and LiCl-KCl-BaCl2 were determined from emf measurements of the formation cell chromium chlorine, and from the potential of the redox couple Cr(III)/Cr(II). These solutions have a nearly ideal behaviour; significant departure from ideality appears only at temperature higher than 500-degrees-C. It was shown that the small value of the excess free enthalpy arose from compensation between entropy and enthalpy terms. The solubility of Cr(II) and Cr(III) chlorides was calculated by chronopotentiometry, It was observed that the dissolution of CrCl3 depended strongly on the structure and size of the salt crystals.