ISOPIESTIC DETERMINATION OF THE ACTIVITY-COEFFICIENTS OF SOME AQUEOUS RARE-EARTH ELECTROLYTE-SOLUTIONS AT 25-DEGREES-C .4. LA(NO3)3, PR(NO3)3, AND ND(NO3)3

The osmotic coefficients of aqueous La(NO3)3, Pr(NO3)3, and Nd(NO3)3 solutions have been measured from 0.1 mol kg-1 to 6.2-6.4 mol kg-1 at 25 °C by using the Isopiestic method. The resulting osmotic coefficients were fitted to semiempirical least-squares equations, and these equations were used to calculate water activities and mean molal activity coefficients. The data up to 2.0 mol kg-1 were also fitted to Pltzer's equation. These data are compared to other available thermodynamic and transport data for rare earth electrolyte solutions. © 1979, American Chemical Society. All rights reserved.