Density and volume properties of MF-K2ZrF6 (M = Li, Na, and K)

Critical evaluation of volume properties (based on density measurements using Archimedean method) of the zirconium-based fluorides melts MF-K2ZrF6 (M = Li, Na, and K) revealed the different properties of KF system in contrast to LiF and NaF systems. Excess molar volume adopts negative values in the entire concentration range for all three investigated systems. Partial molar volumes of K2ZrF6 were obtained by using two different approaches - simple polynomial regression analysis and multicomponent polynomial regression in the form of the Redlich-Kister equation. Finally, the excess partial molar volume of K2ZrF6 in KF shows smaller overall volume contraction that adopts 60% of volume contraction in LiF or NaF systems. The obtained data of density, molar volumes and partial molar volumes were compared with accessible literate data after recalculation to the MFZrF4 coordinates.