Document Type


Subject Area(s)

Chemical Engineering


Molybdenum (VI) oxide reacts with molten LiCl-KCl eutectic at 450° to form MoO2CI2, which probably is present as an anion MoO2Cl4=, and pyromolybdate, Mo2O7=. Both of these species are electrochemically reduced to MoO2, which can be reoxidized to MoO2Cl2 by current reversal. A second reduction step, observed whether MoO3 or Mo2O72− is added to the melt, can be attributed to the reduction of MoO4−−, formed as a secondary reaction product in the first step. The reduction of molybdate proceeds in two steps, the first at −0.85V and the second at −1.75V vs. the 1M Pt(II)/Pt reference electrode. The first step shows an abnormally short transition time, attributable to a slow equilibrium. The second step corresponds to a diffusion-controlled reduction with n = 0.5, yielding a product of the empirical formula Li5Mo2O8.