title: Calorimetric study of the entropy relation in the NaCl-KCl system.
abstract: The heat capacity of one Na-rich and two K-rich samples of the NaCl-KCl (halite-sylvite) crystalline solution was investigated between 5 and 300 K. It deviated positively from ideal behaviour with a maximum at 40 K. The thereby produced excess entropy at 298.15 K was described by a symmetric Margules mixing model yielding [Formula: see text] = 8.73 J/mol/K. Using enthalpy of mixing data from the literature and our data on the entropy, the solvus was calculated for a pressure of 105Pa and compared with the directly determined solvus. The difference between them can be attributed to the effect of Na-K short range ordering (clustering).
authors.affiliation: Materialforschung und Physik, Universität Salzburg, Hellbrunnerstr. 34, A-5020 Salzburg, Austria.
authors.forename: Artur
authors.initials: A
authors.lastname: Benisek
authors.affiliation: Materialforschung und Physik, Universität Salzburg, Hellbrunnerstr. 34, A-5020 Salzburg, Austria.
authors.forename: Edgar
authors.initials: E
authors.lastname: Dachs
keywords: Entropy; Heat capacity; Mixing; Potassium chloride; Sodium chloride; Solvus; Subsolidus