Thermodynamic Properties of Solutions of Group IV Metals Dissolved in Liquid Sodium: II . Sodium‐Tin Solutions

Abstract

Using an emf technique, the thermodynamic properties of dilute sodium solutions containing tin were measured over the temperature range 300° to 500°C Results are reported for solution compositions ranging from 0.82 to 19.04 atomic per cent (a/o) tin, thereby, completing the requisite studies to detail the thermodynamic properties for this system over the entire range of composition. The results, in agreement with earlier findings for the Cd−, Tl−,and systems, show that the deviations from ideal solution behavior cross over from negative to positive at low Sn concentrations. Sodium activity measurements, which were made as a function of decreasing temperature, display a marked change in slope upon transition to a two‐phase region. Appropriate measurements, made as a function of temperature for the two‐phase region, give 13.07 kcal/mole for the enthalpy and 15.65 eu for the entropy of solution. The standard enthalpy and entropy of formation for the compound were also determined; the values are −20.65 kcal/mole and −9.63 eu, respectively.