ON THE ANHYDROUS REDUCED HALIDES OF ZIRCONIUM AND HAFNIUM

摘要

A study was made of reactions of the type M(s) + 3MX4 (g) = 4MX3 (s), where M refers to zirconium or hafnium, and X refers to F, I, r, r I. A pseudo-equilibrium position, found by plotting the extent of reaction versus reaction time, occurred after the reaction had proceeded for 36 to 48 hours. It shifted in favor of the reaction product with increasing temperature, in the range 200°to 700°, and/or increasing pressure, in the range five to fifteen atmospheres. The ease of reduction of MX4 increased considerably from chloride to iodide, and very slightly from hafnium to zirconium. No reaction was found to occur under the above conditions between MF4 and M. The disproportionation reactions were followed both macroscopically and by an x-ray method.