Phase analysis and density of the system K2ZrF6–K2TaF7

Thermal analysis and the Archimedean method were used to determine the phase equilibrium and density of the pseudo-binary system K 2 ZrF 6 –K 2 TaF 7 . Molar volume and excess molar volume were calculated on the basis of the experimental density data. Concentration dependencies of molar volume and molar excess volume for selected temperatures (1,133, 1,153, and 1,173 K) revealed minima at the composition x K 2 ZrF 6 = 0.20 . A “compressibility parameter” for K 2 TaF 7 was introduced for discussion of volume changes of the system; volume contractions were observed. Graphical Abstract Monatshefte_Kubikova_Graphical abstract.eps .