Temperatures of Primary Crystallization and Density of the KF + AlF₃ + LiF + Al₂O₃ Molten System

This work deals with the investigation of the temperatures of primary crystallization and density of the KF + AlF₃ + LiF + Al₂O₃ molten system for three cryolite ratios (CR = 1.3, 1.5 and 1.7). Thermal analysis and the Archimedean method of hydrostatic weighing were used for the determination of studied properties. The dependence of liquidus temperature on composition shows different trends for different CRs, whereas the density increased with increasing content of LiF for all CRs

Physicochemical Properties of the (LiF + CaF₂)_eut + LaF₃ System: Phase Equilibria, Volume Properties, Electrical Conductivity, and Surface Tension

The physicochemical behavior of the molten system (LiF (1) + CaF₂ (2))_eut + LaF₃ (3) has been studied and the phase equilibria, density and volume properties, electrical conductivity, and surface tension have been selected for investigation. Well-established methods for determination of these physicochemical properties of molten salts have been used, such as thermal analysis, the Archimedean method of hydrostatic weighing, and the phase shift and maximum bubble pressure methods. A significant change in all investigated properties was detected in the region of <i>x</i>₃ = 0.04–0.06. In regard to phase equilibria, this region is close to and may contain the eutectic point; in volumetric properties, the initial volume contraction (on increasing mol %) starts to reverse. A sharp change of electrical conductivity reflects the changes in ionic composition, and surface tension also shows different behavior below and above this region

Physicochemical Properties of the (LiF + CaF₂)_eut + LaF₃ System: Phase Equilibria, Volume Properties, Electrical Conductivity, and Surface Tension

The physicochemical behavior of the molten system (LiF (1) + CaF₂ (2))_eut + LaF₃ (3) has been studied and the phase equilibria, density and volume properties, electrical conductivity, and surface tension have been selected for investigation. Well-established methods for determination of these physicochemical properties of molten salts have been used, such as thermal analysis, the Archimedean method of hydrostatic weighing, and the phase shift and maximum bubble pressure methods. A significant change in all investigated properties was detected in the region of <i>x</i>₃ = 0.04–0.06. In regard to phase equilibria, this region is close to and may contain the eutectic point; in volumetric properties, the initial volume contraction (on increasing mol %) starts to reverse. A sharp change of electrical conductivity reflects the changes in ionic composition, and surface tension also shows different behavior below and above this region

Combined Approach for the Structural Characterization of Alkali Fluoroscandates: Solid-State NMR, Powder X‑ray Diffraction, and Density Functional Theory Calculations

The structures of several fluoroscandate compounds are presented here using a characterization approach combining powder X-ray diffraction and solid-state NMR. The structure of K₅Sc₃F₁₄ was fully determined from Rietveld refinement performed on powder X-ray diffraction data. Moreover, the local structures of NaScF₄, Li₃ScF₆, KSc₂F₇, and Na₃ScF₆ compounds were studied in detail from solid-state ¹⁹F and ⁴⁵Sc NMR experiments. The ⁴⁵Sc chemical shift ranges for six- and seven-coordinated scandium environments were defined. The ¹⁹F chemical shift ranges for bridging and terminal fluorine atoms were also determined. First-principles calculations of the ¹⁹F and ⁴⁵Sc NMR parameters were carried out using plane-wave basis sets and periodic boundary conditions (<i>CASTEP</i>), and the results were compared with the experimental data. A good agreement between the calculated shielding constants and experimental chemical shifts was obtained. This demonstrates the good potential of computational methods in spectroscopic assignments of solid-state ⁴⁵Sc NMR spectroscopy