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Methods for the synthesis of LaNi1/3Sb5/3O6 with a rosiaite structure have been developed using citrate method and coprecipitation followed by annealing. The influence of synthesis conditions on the morphology of the samples has been demonstrated. A comparative analysis of the catalytic properties of LaNi1/3Sb5/3O6 synthesized by various methods, in the reaction of CO oxidation has been carried out. The catalyst synthesized by the citrate method demonstrated the greatest efficiency and stability (the temperature of 90% CO conversion was T90 = 336°C). The LaNi1/3Sb5/3O6 surface was studied before and after catalysis by in situ diffuse reflectance IR spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed O2 desorption. It has been shown that the catalytic oxidation of CO on the LaNi1/3Sb5/3O6 surface proceeds according to the Mars–van Krevelen mechanism and is accompanied by redox Sb3+ ↔ Sb5+ processes. It has been established that no contamination of the sample surface occurs during the catalysis process. [ABSTRACT FROM AUTHOR]

Mg-containing solid solutions based on Y2FeTaO7 and formed by various mechanisms of heterovalent substitution were synthesized and had the following compositions: Y2Fe0.55Mg0.3Ta1.15O7, Y2Fe0.625Mg0.3Ta1.075O7, Y2Fe0.7Mg0.3TaO7, Y2Fe0.7Mg0.2Ta1.1O7, Y2Fe0.85Mg0.15TaO7, Y1.85Mg0.15Fe0.925Ta1.075O7, and Y1.85Mg0.15FeTaO7. It was shown that all synthesized solid solutions have a pyrochlore-like layered structure (space group P3121), in which Fe3+ ions are distributed over three structural positions. The magnetic properties of these solid solutions are due to the presence of a small ferromagnetic component in a predominantly antiferromagnetic system and characterize a ferrimagnet or a canted antiferromagnet with the Néel transition at the Néel temperature TN above room temperature. According to the data of magnetic measurements, two magnetic phase transitions to the ordered phase occur in all the studied samples. Along with the TN transition, in weak magnetic fields and below TN, there is a second transition, which is most likely due to a spin reorientation of the Morin type. The existence of magnetic ordering at room temperature in one magnetic sublattice or an internal magnetic field (Hin) was confirmed by Mössbauer spectroscopy. [ABSTRACT FROM AUTHOR]

In this paper, we report the first Bi4Ge3O12-based thin-layer alpha radiation detector. The scintillator was immobilized on a fused silica substrate via pulsed laser irradiation of BGO powder consisting of submicron particles. Laser treatment conditions were shown to influence the morphology and kinetic characteristics of the scintillator. The material we prepared ensures a higher stability of detectors to moisture and air in comparison with its commercially available analogs, while offering a comparable or even higher detection efficiency, and can be used in environmental monitoring, including volumetric alpha activity measurements. [ABSTRACT FROM AUTHOR]

Highly efficient and stable catalysts PdO/LnFe0.5Sb1.5O6, Ln – La, Ce, Pr, Nd, Sm, promising in the reaction of complete methane oxidation have been obtained using the deposition–precipitation method. The catalysts contain complex oxides, which crystallize in a rosiaite-type structure (sp.gr. P31m). These oxides have been used for the first time as support. The catalysts samples are characterized by a uniform distribution of PdOx particles the average size of which is 13 nm. The 90% methane conversion temperature, T90, for PdO/LnFe0.5Sb1.5O6, which were obtained without catalyst prе-activation, lie in the range of 367–382°C and does not depend on the REE ion radius. Catalytic activity dependence on the amount of supported active component is studied and the optimal content in terms of metal equal to 1 wt % Pd is found. The correlations between the synthesis conditions and catalytic activity of PdO/LnFe0.5Sb1.5O6 are established. The catalyst PdO/LaFe0.5Sb1.5O6 with the best catalytic characteristics is studied by X-ray photoelectron spectroscopy, IR spectroscopy, and O2-TPD. According to the XPS-data Pd oxidation state before and after catalytic reaction is Pd2+ in PdO species. The promoting role of the oxide support with rosiaite structure is shown and the mechanism of CH4 complete oxidation on PdO/LnFe0.5Sb1.5O6 is proposed. [ABSTRACT FROM AUTHOR]

The possibility to prepare transparent scintillation composite materials based on SiO2 aerogels with Bi4Ge3O12 filler has been shown for the first time. Effect of gelation catalysts (HF and ammonium hydroxide), solvents (methanol, isopropanol, acetone, methyl cellosolve, and methyl lactate), and supercritical drying conditions (CO2, alcohols) on transparency and textural properties of SiO2 aerogels has been studied. A procedure for Bi4Ge3O12 dispersing in transparent aerogels based on SiO2 has been developed and composite materials containing Bi4Ge3O12 of different morphology have been synthesized. The study of scintillation properties of the prepared samples showed their complete correspondence to the properties of Bi4Ge3O12 single crystals [ABSTRACT FROM AUTHOR]

An isothermal section of the Sm2O3–Fe2O3–Ta2O5 system was constructed in the subsolidus region at 1200°C. A region of the Sm2 – xFe1 + xTaO7 solid solution with the cubic pyrochlore structure (space group Fd m) was found. A study of the polythermal section of the system along the Sm2 – xFe1 + xTaO7 section showed that the previously known compound Sm2FeTaO7 (R) with the structure of rhombohedrally distorted pyrochlore (space group R ) is stable in the temperature range <1200°C. With increasing temperature, Sm2FeTaO7 (R) becomes an intermediate phase, and a reversible transition to the cubic pyrochlore (C) phase is observed. The kinetic hindrances of the transition R → Fd m determine the short-term stability of the R phase at temperatures exceeding the phase transition temperature by 200°C. It was established that cubic pyrochlore exists as the Sm2 – xFe1 + xTaO7 solid solution in the ranges x = 0–0.4 at t ≥ 1200°C and x = 0.15–0.4 at lower temperatures. Two independent methods—Mössbauer spectroscopy and XANES—detected that the rhombohedral phase contains not only Fe3+ ions but also Fe4+ ions. The magnetic properties were studied, and it was shown that both the R phase and the C phase at T < 10 K undergo two magnetic transitions of different types: an antiferromagnetic transition observed in a strong magnetic field at 7.2 and 5.5 K, respectively, and a transition to the spin glass state in a field of 100 Oe at 8.4 and 4.8 K, respectively. It was determined that the spin glass state coexists with short-range antiferromagnetic interactions until 2.3 K. Despite the fact that the R and C phases formally have geometrically frustrated magnetic sublattices, the experimental data showed that frustration manifests itself only in the R phase. [ABSTRACT FROM AUTHOR]

The optical properties of CsSnI3 perovskite thin films were investigated. The thin films were obtained from CsI and SnI2 precursors (special-purity grade, 99.999%, 5N), and also SnI2 (99%) by spin-coating from the corresponding solutions. The films were studied by X-ray powder diffraction analysis, scanning electron microscopy, and optical spectroscopy. It was shown that impurities in the initial components affect the optical properties of the obtained material: the absorption coefficient of the perovskite films synthesized from the special-purity grade SnI2 is higher than those of the films produced from 99% SnI2: 4 × 105 cm–1 and 6 × 105 cm–1, respectively. The optical band gap was estimated using the Tauc and Kubelka–Munk models. [ABSTRACT FROM AUTHOR]

A new compound SmFe0.5Ta1.5O6 has been synthesized and its structure has been calculated from synchrotron powder diffraction data by the Rietveld method. It has been demonstrated that SmFe0.5Ta1.5O6 has an aeschynite structure (space group Pnma). A study of its magnetic properties has shown that the SmFe0.5Ta1.5O6 compound is paramagnetic. [ABSTRACT FROM AUTHOR]

New compounds with the rosiaite type structure LaM1/3Sb5/3O6, M = Co, Ni, and Cu, were synthesized. The compounds belong to quasi-two-dimensional magnets, in which magnetic interactions occur in the layers with a honeycomb structure. It is shown that there is no long-range magnetic order in these compounds. The temperature and field dependences of the magnetization in the compounds with M = Co, Ni indicate the presence of short-range anti-ferromagnetic and ferromagnetic exchange interactions. In the LaM1/3Sb5/3O6, M = Co, Ni, compounds, the interactions occur between Co2+ or Ni2+ ions of isolated magnetic clusters randomly distributed in the paramagnetic matrix in the chains of (M/Sb)O6 octahedrons. These clusters have sizes comparable with the crystal cell size. The LaCu1/3Sb5/3O6 compound is paramagnetic. [ABSTRACT FROM AUTHOR]

Ln2CrTaO7 (Ln = Sm, Gd, Y) pyrochlores are synthesized by the co-precipitation with subsequent annealing. The effect of the precursor composition ((NH4)2Cr2O7, Cr(NO3)3, and CrCl3) on the precipitates reactivity and product microstructure was studied. Samples with an average particle size of 200 nm for Y2CrTaO7, 450 nm for Gd2CrTaO7 and 600 nm for Sm2CrTaO7 were used to study thermodynamic properties. The temperature dependences of heat capacity were measured by the adiabatic calorimetry (13–346.16 K) method and the ratio method using DSC measurements (330–1300 K). The thermodynamic functions of Ln2CrTaO7 compounds were calculated. The absence of polymorphic transitions up to a temperature of 1450°C for all studied compounds is shown. [ABSTRACT FROM AUTHOR]

A procedure for the synthesis of the LaCo1/3Sb5/3O6 layered oxide with a rosiaite structure has been developed. The method is based on the hydrothermal treatment of coprecipitated sediments with their subsequent annealing. The resulting material has proven to be an efficient catalyst in the CO oxidation reaction. This result confirms the prospects of using compounds with the rosiaite structure in oxidative catalysis reactions. [ABSTRACT FROM AUTHOR]

Efficient method for the directed synthesis of ZrO2–Er2O3 luminescent material in nanocrystalline state has been developed. Monodisperse samples of cubic modification with particle size from 5 to 71 nm depending on synthesis conditions have been synthesized. Luminescence spectra due to 4I11/2 → 4I15/2 and 4I13/2 → 4I15/2 transitions of Er3+ ions have been registered upon their excitation by 532-nm radiation. Upconversion luminescence spectra due to 2H11/2, 4S3/2 → 4I15/2, 4F9/2 → 4I15/2 transitions have been registered on excitation to level 4I13/2 of Er3+ ions by 1550-nm radiation. [ABSTRACT FROM AUTHOR]

A comparative analysis has been made for the dielectric and electrorheological properties of suspensions of highly dispersed powders of bismuth ferrites BiFeO3 and Bi2Fe4O9 in polydimethylsiloxane PMS-300. Dielectric characteristics (dielectric constant, dielectric loss tangent) for the suspensions in frequency range 2.5–106 Hz have been determined and non-Debye character of relaxation processes in these systems has been revealed. The measured values of dielectric constant for the disperse bismuth ferrites at zero and infinite frequency (ε0 and ε∞) are 150 and 59 for BiFeO3, 22 000 and 14 for Bi2Fe4O9, respectively. Electrorheological properties of bismuth ferrite suspensions in static electric field (up to 5 kV) in tension, compression, and shear modes have been analyzed. It has been found that the values of electrorheological effect for BiFeO3 suspensions in polydimethylsiloxane PMS-300 are small even at high concentrations of disperse phase (60 wt %). On the contrary, the suspensions of highly disperse Bi2Fe4O9 exhibit distinct electrorheological effect. For 80 wt % Bi2Fe4O9 suspension, the tensile yield point reached ~7 kPa in electric field of 5 kV, while compressive stress was 12 kPa. [ABSTRACT FROM AUTHOR]

X-ray photoelectron spectroscopy has been applied to examine the surface electronic structure of layered oxides CeFe0.5Sb1.5O6 and PrFe0.5Sb1.5O6 with PbSb2O6 structure (sp. g. P‑31m). The analysis of the XP-spectra for both compounds revealed only Ce3+ and Pr3+oxidation state before and after catalytic tests. The observed variation of the Sb5+/Sb3+ and Fe3+/Fe2+ ratios after catalysis can point to that CO oxidation on these catalysts proceeds by virtue of redox transformations Sb3+ ↔ Sb5+ and Fe3+ ↔ Fe2+ with direct involvement of lattice oxygen and anionic vacancies. [ABSTRACT FROM AUTHOR]

(Ln1.8Fe0.2)FeSbO7 (Ln = Pr–Tb) mixed oxides have been synthesized via coprecipitation followed by annealing. According to Rietveld refinement results, all of the oxides have the pyrochlore structure (sp. gr. Fd mz). The (Ln1.8Fe0.2)FeSbO7 compounds have been shown to exhibit high activity for CO oxidation reaction. The best results have been obtained for (Pr1.8Fe0.2)FeSbO7, which has a 90% CO conversion temperature T90 = 385°C. With increasing lanthanide atomic number, T90 rises monotonically from 385 to 550°C in going from Pr to Tb. This behavior is most likely due to the decrease of structural imperfection in the compounds with smaller lanthanide ionic radii. [ABSTRACT FROM AUTHOR]

A novel process has been developed for the preparation of Bi4Ge3O12 (BGO) by self-propagating high-temperature synthesis. In this method, microwave radiation is used for the first time to heat organic fuel (urea), which allows its decomposition to be uniformly activated throughout the reaction mixture. The key synthesis parameters are the pH of the medium, the volume of the liquid phase in the system, and the way in which the starting mixture is homogenized. Varying these parameters has made it possible to reduce the synthesis time to 3 min. We have obtained BGO samples consisting of quasi-spherical particles, potentially attractive for the fabrication of scintillating ceramics. In addition, we have synthesized powders that have an order of magnitude better kinetic scintillation characteristics in comparison with single-crystal BGO and are thus interesting for designing scintillating materials for highly sensitive detectors. [ABSTRACT FROM AUTHOR]

The existence of a wide range of pyrochlore-like (PL) Ln2FeTaO7 compounds (Ln = Pr–Yb, including Y) with a hexagonal structure (space group R ) was shown. Two new low-temperature methods for the synthesis of Ln2FeTaO7 were developed to reduce the production temperature and time, namely, coprecipitation followed by annealing and synthesis in molten salts NaCl/KCl. The synthesis of PL phases was found to involve the formation of a nanocrystalline metastable fluorite phase, the fluorite irreversibly transforming to a PL phase as the crystallization time or temperature increases. No other transitions in Ln2FeTaO7 were recorded by DSC up to the melting point of 1320–1450°C (depending on the composition of the Ln2FeTaO7 compound). The isobaric heat capacity Cp(T) was measured and the thermodynamic functions (entropy, enthalpy increment, and reduced Gibbs energy) were calculated in the temperature range 5–1300 K for Y2FeTaO7 by the way of example. In the low-temperature region of 2–25 K, an abnormal behavior of Cp(T), apparently related to the Y2FeTaO7 magnetic transition, was detected. [ABSTRACT FROM AUTHOR]

A series of LnIII O6 (Ln = La–Tb) complex oxides were prepared by coprecipitation followed by annealing. The phases where Ln = Ce, Pr, Eu, and Tb were prepared for the first time. The 900°С isothermal section of the Ce2Ox–Ga2O3–Sb2Oy phase diagram was plotted. Structures were calculated by the Rietveld method to show that all of the LnGa0.5Sb1.5O6 (Ln = La–Tb) compounds have rosiaite (PbSb2O6) type structures. By the way of example, for LaGa0.5Sb1.5O6 the isobaric heat capacity was determined and thermodynamic functions (entropy, enthalpy increment, and reduced Gibbs energy) were calculated at temperatures in the range from 15 to 1300 K. [ABSTRACT FROM AUTHOR]

Abstract—We have synthesized needle- and platelike α-Bi2O3 and Bi2O2CO3 nanoparticles. The bulk density of the α-Bi2O3 and Bi2O2CO3 powders is 8.5 and 6.9 g/cm3. The dielectric permittivity of α-Bi2O3 and Bi2O2CO3 has been calculated using dielectric permittivity and dielectric loss tangent dispersion measurements in the frequency range from 2.5 × 101 to 1 × 106 Hz for 40% suspensions (0.05 and 0.08 volume fractions of α-Bi2O3 and Bi2O2CO3, respectively) in PMS-300 polydimethylsiloxane. The value of ε∞ has been found to be 5.4 for α-Bi2O3 and 4.9 for Bi2O2CO3. Dielectric spectra of the suspensions have been shown to exhibit no relaxation behavior in the frequency range studied. We have compared the effects of the shape and dielectric permittivity of the particles on the magnitude of the electrorheological effect in them. Using a simple polarization model, we have analyzed the effect of the dielectric characteristics of the filler material on the yield stress τ0 of the suspensions in electric fields from 0 to 4 kV/mm. Using a combination of rheometric and direct microscopic observations, we have explained the effect of the type of filler on the electrorheological effect: the Bi2O2CO3-based ERFs have higher shear and compressive yield stresses, whereas the α-Bi2O3-based ERFs have a higher tensile yield stress. [ABSTRACT FROM AUTHOR]

Abstract—We have synthesized needle- and platelike α-Bi2O3 and Bi2O2CO3 nanoparticles. The bulk density of the α-Bi2O3 and Bi2O2CO3 powders is 8.5 and 6.9 g/cm3. The dielectric permittivity of α-Bi2O3 and Bi2O2CO3 has been calculated using dielectric permittivity and dielectric loss tangent dispersion measurements in the frequency range from 2.5 × 101 to 1 × 106 Hz for 40% suspensions (0.05 and 0.08 volume fractions of α-Bi2O3 and Bi2O2CO3, respectively) in PMS-300 polydimethylsiloxane. The value of ε∞ has been found to be 5.4 for α-Bi2O3 and 4.9 for Bi2O2CO3. Dielectric spectra of the suspensions have been shown to exhibit no relaxation behavior in the frequency range studied. We have compared the effects of the shape and dielectric permittivity of the particles on the magnitude of the electrorheological effect in them. Using a simple polarization model, we have analyzed the effect of the dielectric characteristics of the filler material on the yield stress τ0 of the suspensions in electric fields from 0 to 4 kV/mm. Using a combination of rheometric and direct microscopic observations, we have explained the effect of the type of filler on the electrorheological effect: the Bi2O2CO3-based ERFs have higher shear and compressive yield stresses, whereas the α-Bi2O3-based ERFs have a higher tensile yield stress. [ABSTRACT FROM AUTHOR]

We have prepared glasses in the ZrF4–BaF2–LaF3–AlF3–NaF (ZBLAN) and HfF4–BaF2–LaF3–AlF3–NaF (HBLAN) systems in which fluorine anions are partially replaced by chlorine and bromine anions. Structural changes in the chlorine-substituted glasses have been investigated by Raman spectroscopy and their crystallization behavior has been studied by differential thermal analysis and X-ray diffraction. The results demonstrate a characteristic decrease in glass transition temperature (Tg) and the precipitation of fine-particle crystalline chloride and bromide phases in a temperature range well below the crystallization temperature (Tx) of the fluoride analogues. We have identified phases that crystallize during heat treatment of the glasses at various temperatures. [ABSTRACT FROM AUTHOR]

Anhydrous basic bismuth nitrate Bi6(NO3)2O7(OH)2 was shown to be produced by reacting bismuth nitrate with aqueous ammonia under microwave-assisted hydrothermal treatment as a result of hydrolysis. The composition of the basic nitrate was verified by titration, CHNS analyses, DTG, and IR spectroscopy. Photocatalytic tests showed that Bi6(NO3)2O7(OH)2 has a photocatalytic activity, but its properties are interior to those of α-Bi2O3. [ABSTRACT FROM AUTHOR]

We have developed a process for the synthesis of fine bismuth orthogermanate, Bi4Ge3O12 (BGO), powders in a NaCl/KCl melt and examined the effect of synthesis conditions on the phase composition and morphology of the powders. Our results demonstrate that the synthesized materials compare well in scintillation performance with single-crystal BGO: their scintillation efficiency is 90% relative to single-crystal BGO, with a decay time of 300 ns. [ABSTRACT FROM AUTHOR]

Reactions of nitric acid solutions of bismuth with alkalis have been studied. The effect caused by coprecipitation conditions in the presence of additional agents (EG, PEG 400, or PEG 8000) and without on the phase composition and morphology of α- and γ-BiO has been determined. [ABSTRACT FROM AUTHOR]

A process for the growth of VSe and VTe single crystals using VCl as a transport agent is proposed and experimentally demonstrated. X-ray diffractometry and Laue X-ray photography results indicate that the crystals thus grown are identical in properties to chalcogenide crystals grown using I as a transport agent. The mechanism of chemical vapor transport is discussed and the process conditions are optimized. [ABSTRACT FROM AUTHOR]

A technique has been developed for fluorinating the pyrochlore oxide BiFeFeSbO, and a compound with the composition BiFeSbOF has been obtained. The synthesized oxyfluoride also has the pyrochlore structure (sp. gr. Fd3 m), with a lattice parameter a = 10.4443(1) Å ( R = 5.2). It has been shown that the charge balance upon fluorine substitution for oxygen is maintained not through partial reduction of Fe to Fe but through the incorporation of fluorine into oxygen vacancies. The magnetic behavior of the fluorinated pyrochlore phase is determined by the persisting frustration of the octahedral sublattice, which is responsible for the development of a spin glass state below T = 12 K. The fluorination-induced changes in the anion sublattice led to an increase in the antiferromagnetic exchange interaction between neighboring Fe ions and changes in the dynamic properties of the spin glass phase. [ABSTRACT FROM AUTHOR]

Reaction of hydrochloric acid solutions of bismuth and antimony with ammonia has been studied and effect of coprecipitation conditions of resultant hydroxides on their reactivity has been determined. Annealing conditions for coprecipitation products have been optimized. Effect of surfactants of different nature and concentration on the phase composition, size, and shape of resulting particles have been examined. Nanocrystalline samples of BiSbO have been synthesized. [ABSTRACT FROM AUTHOR]

Optical and vibrational spectra of BiFeGaSbO solid solutions with pyrochlore structure have been studied. It has been shown that the compounds have strongly disordered structure. It has been established that a decrease in iron content causes a marked shift of BiFeGaSbO absorption edge. According to assessment of band gap width, BiGaSbO is the most wide-band compound (2.90 eV), while BiFeSbO is the most narrow-band compound (1.88 eV). [ABSTRACT FROM AUTHOR]

The Bi-La-Fe-Sb-O, Pr-Fe-Sb-O, and Bi-Pr-Fe-Sb-O systems have been shown to contain pyrochlore solid solutions. We have determined the limits of the PrFeSbO and BiLnFeSbO (Ln = La, Pr) solid solutions and shown that there is no compound corresponding to the 'ideal' composition PrFeSbO. Analysis of the magnetic properties of the synthesized compounds indicates that rare earth substitution for bismuth ions has no effect on the spin glass transition and that the spin glass state is only determined by the interaction between the Fe spins on the octahedral site. The Pr paramagnetic ion in PrFeSbO does not participate in the formation of the spin glass state but makes a paramagnetic contribution to the total magnetic susceptibility, which is especially significant at low temperatures. [ABSTRACT FROM AUTHOR]

The crystallization mechanism of chlorine-containing fluorohafnate glasses with the compositions (65-56)HfF · (20- x)BaF · xBaCl · 4LaF · (3- y)AlF · yInF · (5-18)NaF has been studied by X-ray diffraction and differential thermal analysis. The results demonstrate that characteristic features of the glasses are a decrease in glass transition temperature and the precipitation of fine-particle crystalline chloride phases at temperatures below the crystallization temperature of their fluoride analogs. We have studied the effect of the Cl/F ratio in the glass batch and the melt cooling rate on the crystallization behavior of the glasses and determined the heat treatment temperature and time for the formation of transparent glassceramic materials. The luminescence properties of Er-doped fluoride and fluorochloride glasses and glassceramics prepared from them have been investigated in the 1.5-µm range. [ABSTRACT FROM AUTHOR]

Crystallization processes in the BiO-FeO-NaOH system upon microwave-assisted hydrothermal synthesis have been studied to reveal the effect of the mineralizer concentration, temperature, degree of filling of the autoclave, and the preparation of precursors on the phase composition and the morphology of the reaction product. Submicron powders of bismuth ferrite BiFeO have been synthesized. [ABSTRACT FROM AUTHOR]

The thermal behavior of barium and bismuth borate BaBiBO is studied by X-ray powder and single-crystal diffraction in a wide temperature range, as well as by the methods of differential scanning calorimetry and dielectric spectroscopy. Thermal expansion is anisotropic, which is caused by the orientation of BO boron-oxygen groups. With increasing temperature, the degree of anisotropy of thermal expansion increases up to negative. In the temperature range of 700-800 K, an anomaly of the dielectric properties is observed, accompanied by the change of the temperature dependence of the coefficients of thermal expansion and the heat capacity. [ABSTRACT FROM AUTHOR]

It was shown that it is possible to obtain by coprecipitation a complex ternary oxide containing elements dissimilar in their chemical nature. The interaction of acidic solutions of bismuth, iron, and antimony with monoethanolamine and ammonia was studied, and the effect of the coprecipitation conditions on the phase composition and morphology of the reaction products was determined. Samples of nanocrystalline pyrochlore containing bismuth, iron, and antimony were produced for the first time. [ABSTRACT FROM AUTHOR]

60BO-32CaF-8BiO glasses codoped with chromium and neodymium have been prepared for the first time, and their luminescence properties have been studied. The glasses have been shown to contain chromium in two oxidation states. We have obtained luminescence spectra of Cr in octahedral coordination and Cr in tetrahedral coordination. Energy transfer from Bi to Nd and Cr has been demonstrated. [ABSTRACT FROM AUTHOR]

The glass-forming region in the CaF-BiO-BO system has been determined for the first time. We have prepared glasses of various compositions, investigated their physicochemical properties, and examined the effect of rare-earth (La, Nd, Eu, Dy, Er, Tm, Yb) doping on the crystallization behavior of the glasses. Transparent glass-ceramics containing ∼40-nm CaEuF and CaLaF crystallites have been obtained. The luminescence properties of the glasses and glass-ceramics have been studied. [ABSTRACT FROM AUTHOR]

We have studied the effect of mechanochemical activation on the reactivity of BiO + FeO oxide mixtures, assessed the temperature effect on the kinetics of BiFeO formation in the oxide mixtures before and after mechanochemical activation, and optimized the conditions of bismuth ferrite synthesis by solid-state reaction. A material with a BiFeO content of at least 98.3 wt % has been obtained, and its magnetic properties have been investigated. [ABSTRACT FROM AUTHOR]

The kinetics of BiFeO formation from xerogel prepared by reverse coprecipitation were studied at different synthesis temperatures. We examined the influence of annealing temperature on the morphology of the reaction products and optimized synthesis conditions, which allowed us to obtain 99.7 wt % pure BiFeO consisting of crystalline grains less than 50 nm in size. Its magnetic properties were investigated. [ABSTRACT FROM AUTHOR]

We gave studied the crystallization behavior of 30BaO · 25BiO · 45BO glasses doped with EuO to different levels. At a EuO content of 7 mol % or higher, the glasses undergo volume crystallization. The only precipitating phase is a solid solution between europium and bismuth oxides. With increasing europium concentration in the glass, the structure of the crystallites changes from cubic to rhombohedral. We have investigated the morphology, physicochemical properties, and luminescence spectra of the glasses and glass-ceramics. [ABSTRACT FROM AUTHOR]

compound with the general formula BiMgPO was obtained by a solid-state reaction method. Its composition was confirmed using EDAX. The compound belongs to the cubic crystal system (space group I23, no. 197) and has a sillenite-type structure. The lattice parameter a is 10.15704(12) Å. The Rietveld refinement of the crystallographic data revealed mixed tetrahedral sites (2 a) occupied by Mg, P, and Bi in a ratio of 32: 63: 5. The resulting lattice strains are compensated by vacancies in the cationic (2 a) and anionic sites (24 f) and by distortion of the Bi-O framework detected by IR and Raman spectroscopy. [ABSTRACT FROM AUTHOR]

We have prepared europium-doped BaO-Bi2O-B2O glasses and investigated the doping effect on the main physicochemical properties and local structure of the glasses. Using Judd-Ofelt analysis, we calculated intensity parameters (Ω, Ω, and Ω), spontaneous emission probabilities, the radiative lifetime, luminescence branching factors, the quantum yield of luminescence, and the stimulated emission cross sections for D → F transitions. [ABSTRACT FROM AUTHOR]

Single-crystalline species of the novel compounds BaBiBO and CaBiBO with Pna2 structure were successfully grown by the top-seed solution growth (TSSG) method and solid-state recrystallization, respectively. X-ray diffraction methods were used to confirm the symmetry of the crystal structure and to determine unit cell parameters. Normal-mode classification and assignment were performed from the results of polarized Raman and IR absorption measurements on the obtained crystals. The high-frequency part of the vibrational spectra of both materials (580-1400 cm) is reminiscent of the normal modes of the isolated [BO] group. The expected crystal-field induced changes in these modes from group-theoretical considerations provide important clues for the normal-mode assignment of the high-frequency spectral lines. [ABSTRACT FROM AUTHOR]

This work examines the effect of KBF4 additions on the crystallization behavior of glasses based on the multicomponent systems MO-Bi2O3-B2O3 with M = Ca, Sr, and Ba. The glass-ceramic composites obtained contain a δ-Bi2O3-based crystalline phase with a crystallite size of ≃7 nm, evenly distributed over the glass matrix. The 400°C electrical conductivity of the nanocomposites reaches 2 × 10−4 S/cm, and the activation energy is 1.1 eV, typical of anion conduction. These values are comparable to those reported for δ-Bi2O3 ceramics. [ABSTRACT FROM AUTHOR]

This review is devoted to a new nonlinear optical material BiB3O6 (BIBO). It systemizes data on the phase equilibrium, structure, polymorphism, and growth characteristics of single crystals of this compound and considers its main properties and fields of application. The bibliography includes 122 references. [ABSTRACT FROM AUTHOR]

Phase equilibria in the SrO-Bi2O3-B2O3 system were studied using powder X-ray diffraction (XRD) and differential thermal analysis (DTA). Quasi-binary sections were determined, and an isothermal section of the system in the subsolidus region at 600°C was constructed using the crossing spections method. A new ternary compound was found: SrBi2B4O10. The existence of SrBi2B2O7 was verified. Bi2O3-SrB2O4 and Bi4B2O9-2SrO: 3B2O3 polytherms were constructed. [ABSTRACT FROM AUTHOR]

It is shown using Bi12TiO20 as an example that doping of a sillenite phase leads to the formation of a solid solution between it and the Bi12M xO20 ± δ phase corresponding to the dopant. This gives rise to structural features characteristic of the second phase and, accordingly, results in the formation of the corresponding optical centers. Dopant atoms occupy tetrahedral (M) sites. In addition, in the case of heterovalent substitutions the M site is partially occupied by the Bi atoms of [BiO3] groups. The structural features of sillenites are governed by the oxidation state of the M cation. Accordingly, doping with ions in the same oxidation state leads to the formation of similar optical centers and, as a consequence, produces similar changes in the properties of the material. The results obtained are supported by experimental studies of the absorption, circular dichroism, photoinduced absorption, and photoconductivity spectra of doped sillenite crystals in a wide spectral range. [ABSTRACT FROM AUTHOR]

Three-dimensional opal-matrix nanocomposites containing various bismuth selenides and tellurides with a particle size from 25 to 150 nm have been produced by reducing oxygen-containing compounds with supercritical isopropanol. The bismuth: chalcogen ratio in the reduction products has been shown to correlate with that in the starting mixtures, indicating that targeted synthesis in opal pores can be used to controllably fabricate nanocomposites. [ABSTRACT FROM AUTHOR]

The physicochemical properties of BaO-Bi2O3-B2O3 glasses have been studied. The effect of KBF4 additions on the properties of the glasses has been examined. The transmission of the glasses has been correlated with their local structure and composition. [ABSTRACT FROM AUTHOR]

The 600°C (subsolidus) section of the CaO-Bi2O3-B2O3 phase diagram has been studied by x-ray diffraction and differential thermal analysis. A new calcium bismuth borate of composition CaBi2B4O10 has been identified, and the existence of CaBi2B2O7 has been confirmed. According to T-x phase diagram data, these compounds form peritectically at 700±5 and 783±5°C, respectively. [ABSTRACT FROM AUTHOR]

The crystal structure of a new bismuth aluminoborate Bi0.96Al2.37(B4O10)O is studied by single-crystal X-ray diffraction. The Bi0.96Al2.37(B4O10)O single crystals are hexagonal (space group $$P\bar 6$$ 2 m). The unit cell parameters are as follows: a = b = 4.587(4) Å, c = 2.253(9) Å, α = β = 90°, γ = 120°, V = 168.60 Å3, Z = 1. [ABSTRACT FROM AUTHOR]