Calorimetry in Liquid Thallium Nitrate-Alkali Nitrate Mixtures

Publisher Website
Google Scholar
Abstract
The enthalpies of mixing in the binary liquid mixtures of thallium nitrate with lithium-, sodium-, potassium-, and rubidium nitrate have been measured at 350°C. It is found that the molar enthalpy of mixing (ΔHM) varies in a somewhat irregular manner as the size of the alkali ion is varied. In this respect these systems give the appearance of differing in behavior both from the binary alkali nitrates on the one hand, and from the silver nitrate-alkali nitrates on the other. However, it will be shown that the results can be accounted for by an approximate semiempirical expression of the type previously used for the silver nitrate-alkali nitrate systems: ΔHM≅−X(1−X)[U′δ2+U′′δ]In this expression X and (1—X) are the mole fractions of the two components; δ=(dTlNO3—dAlkNO3)/(dTlNO3+dAlkNO3), where d is the sum of the ionic radii in the considered salts, while U′ and U″ are constants. The numerical value of U′ is 140 kcal/mole, the same value as for the previously explored nitrates. The value of U″ is 16 kcal/mole, i.e., of the same order of magnitude as the non-Coulombic contribution to the lattice energy of thallium nitrate.
Keywords

This publication has 3 references indexed in Scilit: