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The temperature dependences of the heat capacity (Cp(T)) and crystal lattice parameters (a(T) and Vu(T)) of barium difluoride, BaF2, as well as the heterovalent (BaF2)0.59(TmF3)0.41 solid solution, in the temperature range of 2–300 K are experimentally studied. Anomalous deviations of the dependences of Cp(T), a(T) and Vu(T) of the solid solution at low temperatures (2–20 K) both in the direction of higher and lower values, due to the rearrangement of the crystal field, as well as the appearance of two-level systems in the metal sublattice of the solution, are revealed. At elevated temperatures (150–300 K), an anomalous feature of the studied characteristics with a deviation towards lower values is also observed, which we attribute to the increased influence of the anharmonicity of the vibrations of the solution lattice. It is established that the occurrence of the mechanisms of the revealed anomalies may be attributed to the structural disorder of the solid solution due to the random nature of the placement of Tm3+ ions when replacing Ba2+ ions in the metal sublattice, as well as the appearance of F− ions in the interstitial spaces of the barium difluoride structure. [ABSTRACT FROM AUTHOR]

• New oxyfluoroniobate glasses were synthesized in the ZnNbOF 5 -BaF 2 -InF 3 system. • The thermal properties of the obtained glasses are determined. • The structures of the glass networks in the system studied are revealed. • Glasses in the ZnNbOF 5 -BaF 2 -InF 3 system show luminescence was properties. • In glasses with luminescent properties, nano-objects 9–13 nm in size were found. Glasses in the ZnNbOF 5 –BaF 2 –InF 3 and ZnNbOF 5 -BaF 2 systems were produced using the ZnNbOF 5 •6H 2 O compound. The structure, thermal and luminescent properties of the obtained glasses were studied with IR-, Raman, SAXS, luminescent spectroscopy methods, calorimetry and X-ray diffraction. The highest range of thermal stability and resistance of glass to crystallization has been established for the glass of 20ZnNbOF 5 –40BaF 2 –40InF 3 composition. This value is an order of magnitude higher than in glasses of the same system, but not containing InF 3. Glasses networks are formed from polyhedra of InF 6 , NbO 2 F 4 and NbO 3 F 3. For all glasses containing InF 3 , photoluminescence contribution which depends on the concentration of indium trifluoride in the glass was recorded. This contribution corresponds to the emission levels of 542, 573, 673, 751 nm. Luminescent properties are shown by glasses in which nanoobjects (nanoinhomogeneities) in size of 9-13 nm were detected by SAXS method. [ABSTRACT FROM AUTHOR]

• The copolymers products of DUPONT™ TEFZEL® ETFE 750 and Fluon® AGC ETFE TL-581 were characterized. • During pyrolytic processing of the copolymers, the degradation product was obtained. • The basis of the molecular structure of all three products studied is a chains of fragments of [-CH 2 -CH 2 -CF 2 -CF 2 -] n. • The molecular chains in structure of degradation product are shorter and are closed by the –HF-CF 2 terminal groups. • The product of degradation differs from the initial objects in morphology and thermal properties. The glasses in the MnNbOF 5 -BaF 2 -InF 3 -ErF 3 and CdNbOF 5 -BaF 2 -InF 3 systems have been obtained and investigated by means of IR- and Raman spectroscopy. The structures of glass networks are discussed. The analysis of the inelastic light scattering spectra are used to identify the contribution of the Er3+ photoluminescence in the glasses studied. The contribution of the indium photoluminescence into the inelastic light scattering spectrum of the glasses in the СdNbOF 5 -BaF 2 -InF 3 system has been established at scattering excitation by the laser with the wavelength of 532 nm. [ABSTRACT FROM AUTHOR]