Kinetics and mechanism into preparation of samarium-, europium- and ytterbium dichlorides and their some properties

A kinetic study has been made of the reaction of hydrogen with anhydrous trichlorides of samarium, europium and ytterbium in the temperature ranges 20-710, 20-480 and 20-660 deg and hydrogen pressures 0.02-1.0 atm, as well as of the process of oxidation of dichlorides of these elements by hydrogen chloride in the temperature ranges 560-660 deg, 280-360 and 450-585 deg. Activation energies of the process of reduction of trichlorides of samarium, europium and ytterbium were found to be 18.9; 28.9; 25.7 kcal/mole, respectively. The results of kinetic studies allowed conditions of reduction of trichlorides to be proposed to obtain anhydrous dichlorides of high purity. The pressure of saturated vapours of dichlorides obtained was determined in the temperature ranqe 620-1005 deg. Data obtained on the rate of evaporation of dichlorides allowed calculation of the dependence of the vapour pressure of these compounds on temperature in the form of a two-member equation