ELECTROCHEMICAL REDUCTION PRODUCTS OF CHROMIUM(6) IN MOLTEN LITHIUM CHLORIDE-POTASSIUM CHLORIDE EUTECTIC

The electrochemical reduction product of K2Cr04 dissolved in a LiCl-KCl eutectic containing dissolved MgCl2 is characterized as a single, unstoichiometric compound having the empirical formula LixMgyCrO4 where x + 2y = 5. The values of x and y are found to depend upon the conditions of the electrolysis. X-ray powder diffraction shows the compound to have a face-centered cubic structure with an “a” parameter of 4.182 Å. The thermal and pressure stability of the compound are also investigated. The electrochemical reduction of K2Cr2O7 or CrO2Cl2 in the presence of MgCl2 is complicated by chemical attack of the cathode causing a mixture of compounds to be deposited on the electrode surface. Also, oxide ion is released to the bulk melt altering the oxygen to chromium ratio of the Cr(VI) species being transported to the electrode surface. © 1969, American Chemical Society. All rights reserved.