The results of the synthesis of complex YErYbNbO7 paraniobate using different methods are presented. The chemical composition of the final synthesis products was determined. The peculiarities of the thermal behavior of the precursors are revealed. Crystallographic parameters of single phase samples were calculated and crystallite sizes were determined.

A two-stage technique has been developed for X-ray fluorescence (XRF) analysis of Y3–xYbxNbO7 (x = 0–3) rare-earth paraniobates, suitable for use as thermal barrier coating materials. In the first stage, a preliminary composition of ceramic samples and intermediate synthesis products was determined by rapid semiquantitative analysis using the fundamental parameter method. In the second stage, the quantitative composition of the samples was determined using calibration curves. To obtain the calibration curves, a series of reference samples containing 3.16–56.55 wt

Determination of impurities in Ta- and Nb-based materials is a necessary operation in supporting technological processes. The existing approaches involve the transfer of a sample into a solution with subsequent isolation of impurities. This procedure is rather complicated and takes a lot of time. For this reason, it is of interest to study the possibilities of direct analysis of solid-phase samples of materials, e.g., X-ray fluorescence analysis (XRF). The usual scheme of X-ray fluorescence analysis, which involves the experimental construction of calibration characteristics for each element to be determined, requires using a large number of reference samples containing a rather wide range of impurities. We present the results of preliminary characterization of samples of technical-grade tantalum and niobium and products on their base. It is shown that for starting materials, only a significant absence of impurities can be determined using XPA, but even for sintered niobium hydride and Ta powder, XPA can be used as a method for rapid assessment of the composition. A SPECTROSCAN MAX GVM crystal-diffraction spectrometer can be used for analysis and a standard software that implements the fundamental parameter method (FPA) can be used for calibration. In this case, the obtained values of the content of impurities may differ by 1 – 2 orders of magnitude from the reference values. However, such an accuracy is often enough to correct technological processes. The limits of detecting impurities by XRF in Ta- and Nb-based materials are revealed: for elements determined by K -series (from Ti to Co), the detection limits lie in the range from 30 to 60 ppm, whereas for the elements determined by M -series (Ta) the detection limit is approximately 200 ppm and for L -series (Nb) the detection limit is in the range from 100 to 150 ppm.

Currently, ABX3 nanoparticles (NPs) based on lead halides attract the attention due to their unique optical properties and a wide range of applications. The preparation of NPs with lead as a partial or complete replacement is particularly interesting because of the toxicity of this chemical element and most of its compounds. In this study, we propose a modified method for perovskite NPs synthesis using manganese as a partial replacement for lead. The results obtained describe the structures, shapes, and dimensions of the synthesized nanoparticles. It has been shown that partial replacement of lead with manganese leads to the appearance of new photoluminescence bands in the region of 600 nm.

To maintain the single-phase nature of the cubic solid solution Ba2(Y, Cu, Mo)2O6, which is prone to polymorphism, titanium oxide was used. As a result of the synthesis by gel burning, annealing at 1000°C, and subsequent cooling in an inertial thermal mode, the cubic modification F 4̅ 3m of Ba5Y2CuMoTiO14 was obtained for the first time without an admixture of perovskite Fm3m. A comparative study of samples Ba4Y2CuMoO11 and Ba5Y2CuMoTiO14 was carried out using X-ray powder diffraction, X-ray fluorescence spectrometry, IR spectroscopy, and diffuse reflectance spectroscopy.

A two-stage technique for X-ray fluorescence analysis of ceramic samples of composition Y 3– x Yb x NbO 7 (where x = 0 – 3) has been developed. At the first stage, using the method of fundamental parameters (FPM), a rapid semi-quantitative analysis of ceramic samples and products of intermediate synthesis was carried out to determine their preliminary composition. At the second stage, the quantitative composition of the samples was determined using the constructed calibration dependencies. To construct calibration dependencies a series of reference samples containing 3.16 – 56.55% Y, 8.78 – 71.0% Yb, and 12.83 – 19.70% Nb was synthesized using a method similar to that used for preparation of the ceramic samples under study. Analytical lines of elements free from spectral overlaps and XRF conditions (current and voltage of an X-ray tube, exposure time, method of taking into account the background near the analytical line) were selected. The relative standard deviation of the results of Y, Yb, and Nb determination in ceramic samples did not exceed 0.66%, the relative error was no more than 1.63%. The results obtained were compared with the calculated content of analytes in the samples of stoichiometric composition and with the results of ICP-AES analysis of real ceramic samples. The developed technique provides determination of the main components of ceramic samples and can be used for analytical control of synthesis of rare earth paraniobates.

Polycrystalline samples of the pseudobinary system Ba2YMoO6–[Ba2YCuO5] were synthesized using the gel combustion method. The obtained samples were investigated using X-ray diffraction and photoluminescence spectroscopy. The substitution of Mo with Cu led to the stabilization of cubic phases Fm3̅m and F4̅3m of the solid solution Ba2YMo1 – xCuxO6 – δ (0 ≤ x ≤ 0.5) in air.

Samples of Mg3 – nNinBPO7 (n = 0–3), synthesized by gel combustion followed by annealing at 980°C and cooled in the inertial-thermal mode, were studied by X‑ray powder diffraction, infrared spectroscopy, and X-ray fluorescence spectrometry. For the first time, the crystalline phase of Ni3BPO7 with the β-Zn3BPO7 structure has been experimentally obtained. When the composition of the samples changed from Mg3BPO7 to Ni3BPO7, a region of coexistence of α‑Mg3BPO7 and β-Ni3BPO7 phases was found. An analysis of the diffuse reflectance spectra of the Mg1.5Ni1.5BPO7 sample showed the presence of Ni2+ cations in an arrangement not symmetric octahedral or tetrahedral.

Mg 3 – n Ni n BPO 7 samples ( n = 0–3) were synthesized by gel combustion followed by annealing at 980°C, cooled under inertial-thermal conditions, and then studied by X-ray powder diffraction analysis, IR spectroscopy, and X-ray fluorescence spectrometry. A crystalline phase of Ni 3 BPO 7 with the β-Zn 3 BPO 7 structure was experimentally obtained for the first time. When varying the composition of the samples from Mg 3 BPO 7 to Ni 3 BPO 7 , in borophosphate, a region of coexistence of α‑Mg 3 BPO 7 and β-Ni 3 BPO 7 was discovered. Analysis of diffuse reflectance spectra of Mg 1.5 Ni 1.5 BPO 7 showed the presence of Ni 2+ cations in an environment different from the symmetrical octahedral or tetrahedral environment.

Samples of the composition Ce 0.9 (Mg 1 – x Ni x ) 0.1 O 2 (0 ≤ x ≤ 1, step x = 0.1) have been obtained by gel combustion followed by hydrothermal treatment. X-ray powder diffraction data have showed that after gel combustion and annealing at 1100°C, composite CeO 2 (fluorite structure)/solid solution Mg 1 – x Ni x O (halite structure) is formed, and additional hydrothermal treatment followed by annealing promotes the formation of limited solid solution Ce 0.9 (Mg 1 – x Ni x ) 0.1 O 2 . According to the results of IR spectroscopy, the CeO 2 /Mg 1 – x Ni x O composite does not adsorb CO 2 even in the presence of water vapor, which is also confirmed by diffuse reflectance spectra in the UV-visible region. On the contrary, the Ce 0.9 (Mg 1 – x Ni x ) 0.1 O 2 solid solution absorbs CO 2 , as evidenced by the results of IR spectroscopy and thermogravimetric analysis.

The Mg3 – nNinBPO7 (n = 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0) samples were prepared by solid-phase reactions at 980°C followed by inertial cooling, and then were characterized by X-ray powder diffraction, IR spectroscopy, diffusive reflectance and X-ray fluorescence spectrometry. It was for the first time that experiments yielded Ni3BPO7 crystals having the β-Zn3BPO7 non-centrosymmetrical hexagonal structure. The α-Mg3BPO7 and Ni3BPO7 coexistence range was determined. The diffuse reflectance spectra of an Mg1.5Ni1.5BPO7 sample featured a strong Ni2+ absorption band in the blue spectral range.

The Mg3 – nNinBPO7 (n = 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0) samples were prepared by solid-phase reactions at 980°C followed by inertial cooling, and then were characterized by X-ray powder diffraction, IR spectroscopy, diffusive reflectance and X-ray fluorescence spectrometry. It was for the first time that experiments yielded Ni3BPO7 crystals having the β-Zn3BPO7 non-centrosymmetrical hexagonal structure. The α-Mg3BPO7 and Ni3BPO7 coexistence range was determined. The diffuse reflectance spectra of an Mg1.5Ni1.5BPO7 sample featured a strong Ni2+ absorption band in the blue spectral range.

Samples of the composition Ce0.9(Mg1 – xNix)0.1O2 (0 ≤ x ≤ 1, step x = 0.1) have been obtained by gel combustion followed by hydrothermal treatment. X-ray powder diffraction data have showed that after gel combustion and annealing at 1100°C, composite CeO2 (fluorite structure)/solid solution Mg1 – xNixO (halite structure) is formed, and additional hydrothermal treatment followed by annealing promotes the formation of limited solid solution Ce0.9(Mg1 – xNix)0.1O2. According to the results of IR spectroscopy, the CeO2/Mg1 – xNixO composite does not adsorb CO2 even in the presence of water vapor, which is also confirmed by diffuse reflectance spectra in the UV-visible region. On the contrary, the Ce0.9(Mg1 – xNix)0.1O2 solid solution absorbs CO2, as evidenced by the results of IR spectroscopy and thermogravimetric analysis.

The Mg3 – nNinBPO7 (n = 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0) samples were prepared by solid-phase reactions at 980°C followed by inertial cooling, and then were characterized by X-ray powder diffraction, IR spectroscopy, diffusive reflectance and X-ray fluorescence spectrometry. It was for the first time that experiments yielded Ni3BPO7 crystals having the β-Zn3BPO7 non-centrosymmetrical hexagonal structure. The α-Mg3BPO7 and Ni3BPO7 coexistence range was determined. The diffuse reflectance spectra of an Mg1.5Ni1.5BPO7 sample featured a strong Ni2+ absorption band in the blue spectral range.

A technique for arc atomic emission analysis of cerium oxide has been developed which meets today’s requirements for the accuracy and sensitivity of the impurity determination. The range of impurities that can be determined is significantly expanded compared to the standardized method of the 1970s. This improvement of metrological characteristics has been primarily attained through the use of instrumental capabilities of Grand Globula, an atomic emission facility distributed by VMK-Optoelektronika (Russia). To specify balanced conditions for the determination of 15 rare earth element impurities and another 19 elements, analytical lines have been selected and the dependence of their intensity on the operational mode of the generator, the shape and size of the electrodes, the distance between electrodes, the ratio of the masses of the analyzed sample and graphite powder, and the presence of various carriers (Ga2O3, NaCl, NaF, KCl, S, GeO) has been analyzed. In studying impurity evaporation curves, an exposure time has been determined that is sufficient for their complete evaporation (100–120 s). The metrological characteristics of the proposed procedure for the analysis of cerium oxide have been evaluated in comparison with the standardized method.

A possibility of using S,N-containing sorbents for the analysis of materials based on rare earth element compounds with the determination of impurities in the sorption concentrate by arc atomic emission spectrometry is studied. The properties of S,N-containing sorbents in aqueous solutions and various rare earth matrices are studied. A methodological approach to the sorption preconcentration of impurities in REE-based materials followed by a direct analysis of the sorption concentrate by arc atomic emission spectrometry is described. The results of the development of a spectrochemical method for determining impurities in rare earth element materials are presented, and performance characteristics are evaluated.

Samples of the composition Ce0.9(Mg1 – xNix)0.1O2 (0 ≤ x ≤ 1, step x = 0.1) have been obtained by gel combustion followed by hydrothermal treatment. X-ray powder diffraction data have showed that after gel combustion and annealing at 1100°C, composite CeO2 (fluorite structure)/solid solution Mg1 – xNixO (halite structure) is formed, and additional hydrothermal treatment followed by annealing promotes the formation of limited solid solution Ce0.9(Mg1 – xNix)0.1O2. According to the results of IR spectroscopy, the CeO2/Mg1 – xNixO composite does not adsorb CO2 even in the presence of water vapor, which is also confirmed by diffuse reflectance spectra in the UV-visible region. On the contrary, the Ce0.9(Mg1 – xNix)0.1O2 solid solution absorbs CO2, as evidenced by the results of IR spectroscopy and thermogravimetric analysis.

An approach to sorptive separation of Se (IV) from solutions on a novel S,N-containing sorbent with subsequent determination of the analyte in the sorbent phase by micro-x-ray fluorescence method is presented. The sorbent copolymethylenesulfide-N-alkyl-methylenamine (CMA) was synthesized using «snake in the cage» procedure and proven to be stable in acid solutions. Conditions for quantitative extraction of Se (IV) were determined: sorption in 5 M HCl or 0.05 M HNO3 solutions when heated to 60°C, phase contact time being 1 h. The residual selenium content in the solution was determined by inductively coupled plasma mass spectrometry (ICP-MS) using 82Se isotope. The absence of selenium losses is proved and the mechanism of sorption interaction under specified conditions is proposed. The method of micro-x-ray fluorescence analysis (micro-RFA) with mapping revealed a uniform distribution of selenium on the sorbent surface. The possibility of determining selenium in the sorbent phase by micro-RFA is shown. When comparing the obtained results with the results of calculations by the method of fundamental parameters, it is shown the necessity of using standard samples of sorbates to obtain correct results of RFA determination of selenium in the sorbent phase.

The effectiveness of using materials based on rare earth elements (REE) largely depends on their impurity composition, which affects their structure and properties. Before the analytical quality control of REE-based materials and initial substances for their production, it is necessary to determine both macrocomponents and impurity elements with high sensitivity and accuracy. A complex of atomic emission and mass spectral analytical methods is often used for the determination of impurities in REE-based materials in the range from 10–5 to 5.0 wt.%. However, the analysis of such materials, even using these modern high-sensitivity methods is a difficult task due to spectral and matrix interferences. Therefore, different preliminary separation/concentration procedures are needed to determine both rare earth and other impurities. This article reviews publications is devoted to preconcentration methods for spectral and mass spectral analysis of REEbased materials and, in part, a number of other analytical techniques. It was shown that the most common approaches are liquid extraction and chromatography. Sorption, cloud-point extraction and coprecipitation are also used. There is no universal method. Each of the methods discussed in this article has its own advantages and limitations. The analytical completion of the method confirms the effectiveness of the selected separation/concentration method in each specific case.

An approach to the simultaneous isolation of As(III) and Se(IV) from solutions on a new S,N-containing sorbent followed by determination of the analyte in the sorbent phase by total reflection X-ray fluorescence (TXRF) is proposed. To match the goal, a sorbent with a branched structure is synthesized on the basis of polyacrylamide modified with formaldehyde and hydrogen sulfide. This is a heteroatomic copolymer containing sulfide bridges and crosslinking by a tertiary amine in its chain. Conditions for the quantitative coextraction of As(III) and Se(IV), namely, sorption in 1 M solutions of HNO3 in the presence of calcium ions, heating up to 60°C, and phase contact time of 1 h, are determined. The mechanism of sorption interaction of the analytes under specified conditions is discussed. It is found that 100-fold excesses of iron, zinc, and copper do not interfere with the extraction of the analytes; therefore, it is possible to apply the sorbent for the extraction of As(III) and Se(IV) from different types of raw materials and processed products. A procedure for the direct X-ray fluorescence quantification of arsenic and selenium with Sr of 0.09 and 0.08, respectively, in the sorbent phase is developed. The correctness of the results is confirmed by ICP-MS upon the analysis of aqueous reference solutions after the dissolution of the sorbate in HNO3 (1 : 1).