Interaction of uranium, lanthanum, nobium and ruthenium with sodium fluorides

The reaction of uranium, lanthane, niobium and ruthenium with sodium fluoride is studied above 1000 deg C under unequilibrium conditions. Uranium, lanthane and niobium are found to react with NaF yielding the respective fluorides. Ruthenium does not react with sodium fluoride. Intensity of reaction increases in the series: Nb-U-La. The reaction rates and their temperature dependences are found. The reaction intensity is defined by thermodynamical data