Conductivity and hydration of fluorite-type La6-x WO12-1.5x phases (x=0.4; 0.6; 0.8; 1)

Solid-phase synthesis was used to obtain four phases from the region of cubic fluorite-type La6WO12-La10W2O21 (La5WO10.5) solid solution. The temperature dependence of conductivity was measured using the impedance spectroscopy technique in the atmosphere of dry and humid air and also when was varied from 0.21 to 10(-20) atm. Ionic transport numbers t (ion) are calculated (0.6 to 0.9). It was shown that the La5.6WO11.4 phase had a relatively high stability towards hydrolysis, as the value of its conductivity dropped negligibly (as compared to other studied samples) after long-term sample conditioning in a humid atmosphere. Activation energies of hole (0.85 to 0.98 eV) and proton (0.49 to 0.56 eV) conductivity were calculated. The method of thermogravimetric analysis was used to determine the phase hydration degree in the course of cooling from 980 to 200A degrees C at . Hydration enthalpies Delta H (hydr) (52 to 67 kJ/mol) were calculated.