Single crystals of Cr2O3 have been grown by means of electrolysis on a 1:100 stoichiometric mixture of CrO3 and cesium molybdate, Cs2MoO4, fused at 1000degreesC in an ambient atmosphere. Potentiometric measurements on the molten salts have shown the existence of a critical voltage of -320 mV below which hexagonal platelets-shaped single-crystalline Cr2O3 is grown on the surface of the working electrode. Coulometry measurements have revealed that the Cr ions are at their highest oxidation state of Cr+6 in the molten electrolyte, which suggests that the electric reduction of Cr+6 to Cr+3 drives the single-crystal growth of Cr2O3. (C) 2004 Elsevier B.V. All rights reserved.