Bismuth-germanate glasses, which are well known as a promising active medium for broadband near-infrared spectral range fiber lasers and as an initial matrix for nonlinear optical glass ceramics, have been synthesized in a 5–50 mol% Bi₂O₃ wide concentration range. Their structural and physical characteristics were studied by Raman and FT-IR spectroscopy, differential scanning calorimetry, X-ray diffraction, optical, and luminescence methods. It has been found that the main structural units of glasses are [BiO₆] and [GeO₄]. The growth in bismuth oxide content resulted in an increase in density and refractive index. The spectral and luminescent properties of glasses strongly depended on the amount of bismuth active centers. The maximum intensity of IR luminescence has been achieved for the 5Bi₂O₃-95GeO₂ sample. The heat treatment of glasses resulted in the formation of several crystalline phases, the structure and amount of which depended on the initial glass composition. The main phases were non-linear Bi₂GeO₅ and scintillating Bi₄Ge₃O₁₂. Comparing with the previous papers dealing with bismuth and germanium oxide-based glasses, we enlarge the range of Bi₂O₃ concentration up to 50 mol% and decrease the synthesis temperature from 1300 to 1100 °C.

A simple method of synthesis of high pure tris(8-hydroxyquinoline)aluminum (Alq₃) from commercial available 5N Al₂O₃ and 8-hydroxyquinolinol has been developed. One-step exchange chemical reaction has been conducted under controlled 8-hydrixyquinoline vapor at a temperature of 190–240 °C with water removal by phosphorus anhydride. According to analysis of inductively coupled plasma mass-spectrometry, the chemical purity of synthesized Alq₃ was 99.998 wt%. Photoluminescence of the synthesized Alq₃ has been measured and slightly differed from those of Alq₃ obtained by traditional organic synthesis.

A laboratory technology for a new ultra-low background hybrid material (HM) which meets the requirements for neutron absorption with simultaneous neutron detection has been developed. The technology and hybrid material can be useful for future low background underground detectors designed to directly search for dark matter with liquid noble gases. The HM is based on a polymethylmethacrylate (PMMA) polymer matrix in which gadolinium nuclei are homogeneously distributed up to 1.5 wt% concentration in polymer slabs of 5 cm thickness. To determine the 65 impurity elements by the inductively coupled plasma mass-spectrometry (ICP-MS) technique in the Gd-based preparations in 100–0.01 ppb range, the corresponding method has been developed. Limits of determination (LD) of 0.011 ppb for uranium, and 0.016 ppb for thorium were achieved. An analysis of Gd raw materials showed that the lowest contents of U and Th (1.2–0.2 ppb) were detected in commercial Gd-based preparations. They were manufactured either from secondary raw materials (extraction phosphoric acid) or from mineral raw materials formed in sedimentary rocks (phosphogypsum). To produce the Gd-doped HM the commercial GdCl₃ was purified and used for synthesis of low-background coordination compound, namely, acetylacetonate gadolinium (Gd(acac)₃) with U/Th contents less than LD. When dissolving Gd(acac)₃ in methylmethacrylate, the true solution was obtained and its further thermal polymerization allowed fabrication of the Gd-doped PMMA with ultra-low background.

The general procedure for measurement of impurities in hot zones of high-temperature growth setups is proposed and developed. In the first step, we prepared extra-pure 15 × 15 × 8 mm collecting cubes from composite graphite by high-temperature annealing in dry dynamic vacuum. The collecting cubes were placed in different parts of the hot zones of growth setups. We tested two types of crystal growth setups: single- and multi-crucible growth setups of a VGF configuration for A^IIIB^V semiconductors’ crystal growth. The hot zones of the setups were built from different types of graphite materials and high-temperature dielectric ceramics (BN and Al₂O₃) as insulators. The growth setups with collecting cubes without raw crystal materials were heated to operating temperatures, exposed for certain operating periods, and cooled to room temperature. The cubes were taken off and analyzed by extraction of condensed impurities into an analytic super-pure acid. The extracted impurities in the acid were determined by ICP-MS analysis. We showed that the hot zone of a single-crucible growth setup was nearly twice as pure (averaged 2.45 mg/g) compared with the hot zone of a multi-crucible setup (averaging 4.06 mg/g) because of the different graphite materials of the constructions.

A comprehensive study of the thermodynamic conditions (temperature, composition) of the existence of the cubic phase within the limits of homogeneity region in the quasi-binary PbF2-EuF3 system was carried out. Solid solution samples were obtained by solid-phase synthesis and co-precipitation technique from aqueous nitrate solutions. Phase equilibria were investigated in two regions: the solvus line in the range of 0-10 mol% EuF3 and the region of existence of the ordered rhombohedral R-phase in the range of 35-45 mol% EuF3. The structure of phases in the PbF2-EuF3 system was examined at temperatures below the phase transition temperature in lead fluoride (365°C). The possibility of obtaining a single-phase preparation of a cubic phase of high purity in 0-37 mol% EuF3 composition range has been demonstrated. The region of existence of the ordered rhombohedral R-phase in the concentration range from 37-39 to 43-44 mol% EuF3 was defined using X-ray phase analysis, optical probing, and Raman scattering.

Fluoride solid solutions exhibit exceptional optical and thermodynamic properties that make them valuable for advanced technological applications, and the PbF₂-EuF₃ system represents a particularly promising quasi-binary system for developing high-performance materials. However, the comprehensive understanding of the thermodynamic conditions governing phase equilibria and the precise boundaries of homogeneity regions in this system remains incomplete, limiting the rational design of single-phase materials with desired properties. Therefore, we conducted a comprehensive investigation of the thermodynamic conditions (temperature and composition) controlling the existence of cubic and rhombohedral phases within the homogeneity regions of the PbF₂-EuF₃ system. Solid solution samples were synthesized using both solid-phase synthesis and co-precipitation techniques from aqueous nitrate solutions. Phase equilibria were systematically investigated in two critical regions: the solvus line spanning 0–10 mol% EuF₃ and the ordered rhombohedral R-phase region spanning 35–45 mol% EuF₃. Structural characterization was performed at temperatures below the phase transition temperature in lead fluoride (365 °C) using X-ray phase analysis, optical probing, and Raman scattering. Our investigation successfully demonstrated the possibility of obtaining cubic preparations of high purity across the 0–37 mol% EuF₃ composition range. Additionally, we precisely defined the region of existence of the ordered rhombohedral R-phase within the concentration range of 37–39 to 43–44 mol% EuF₃. These findings provide essential thermodynamic data for the rational design of PbF₂-EuF₃ solid solutions and establish clear compositional boundaries for obtaining desired phase structures in this technologically important fluoride system.