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-Bi 2 O 3 has been determined.

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 BiSbO4 have been synthesized.

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.

Crystallization processes in the Bi2O3-Fe2O3-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 Bi2Fe4O9 have been synthesized.

Исследованы процессы кристаллизации в системе Bi2O3 Fe2O3 NaOH при гидротермально-микроволновом воздействии и установлено влияние концентрации минерализатора, температуры, степени заполнения автоклава и способа подготовки прекурсоров на фазовый состав и морфологию продукта реакции. Синтезированы субмикронные порошки феррита висмута Bi2Fe4O9.

Впервые определена область стеклообразования в системе CaF2 Bi2O3 B2O3. Синтезированы стекла различного состава и изучены их физико-химические характеристики. Рассмотрено влияние РЗЭ (La, Nd, Eu, Dy, Er, Tm, Yb) на кристаллизационную способность стекол. Получены образцы прозрачной стеклокерамики, содержащей кристаллиты Ca1 - xEuxF2 и Ca1 - xLaxF2 размером 40 нм. Исследованы люминесцентные свойства синтезированных стекол и стеклокерамики.

The kinetics of BiFeO3 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 BiFeO3 consisting of crystalline grains less than 50 nm in size. Its magnetic properties were investigated.

The interaction in the system Bi(NO3)3-K3HCit-(H2O + glycerol) was studied by chemical analysis and pH titration over a wide range of ratios between the initial components. Solid phases of the compositions Bi(OH)3−3x HCit x · nH2O and KBiCit · H2O were isolated and investigated by X-ray powder diffraction and differential thermal analyses and IR spectroscopy. The effect of the chemical nature of the alkali metal on the solubility in the system under consideration was demonstrated.

Изучена кинетика образования BiFeO3 при различных температурах синтеза из ксерогеля, полученного методом обратного химического соосаждения. Рассмотрено влияние температуры отжига на морфологию продуктов реакции. Оптимизированы условия синтеза и получен материал с содержанием BiFeO3 не менее 99.7 мас. % и с размерами кристаллических зерен менее 50 нм. Исследованы его магнитные свойства.

The glass-forming region in the CaF 2 -Bi 2 O 3 -B 2 O 3 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 Ca 1 − x Eu x F 2 and Ca 1 − x La x F 2 crystallites have been obtained. The luminescence properties of the glasses and glass-ceramics have been studied.

The reaction in a Bi(NO3)3-Na3Hcit-(H2O + glycerol) system was studied in a wide range of component ratios by the solubility method and pH-metry in combination with chemical analysis of solid phases. Poorly soluble phases of Bi(Hcit) x (OH)3(1 − x) · mH2O (x < 1) and sodium bismuth citrate NaBiCit · 3H2O were obtained. The compounds synthesized were characterized, and their compositions were refined by X-ray diffraction, DTG, and IR spectroscopy.

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.

A novel compound, KBi(C6H4O7) · 3.5H2O (I), has been synthesized in the Bi(NO3)2-K3(HCit) system (HCit3− is an anion of citric acid C6H8O7) at a component ratio (n) of 8 in a water-glycerol mixture, and its crystal structure has been determined. The crystals are unstable in air. The crystals are triclinic: a = 7.462 Å, b = 10.064 Å, c = 17.582 Å, α = 100.27°, β = 99.31°, γ = 105.48°, V = 1221.2 Å3, Z = 2, space group \(P\bar 1\). In the structure of I, asymmetric binuclear fragments [Bi2(Cit4−)2(H2O)2]2− are linked through inversion centers into polymeric chain anions. Ions K+ and crystal water molecules are arranged in channels between the chains. The Bi(1)...Bi(2) distances in the binuclear fragment are 4.62 Å, and the Bi(1)...Bi(1) and Bi(2)...Bi(2) distances between bismuth atoms in the chain are 5.83 and 5.95 Å, respectively. The chains are linked through bridging oxygen atoms of the ligands Cit to form layers. In the centrosymmetric four-membered chelate ring Bi2O2 formed through Bi-O(Cit) bonds, the distances Bi(1)-Bi(1) are equal to 4.55 Å, and Bi(1)-O are 2.66 and 2.84 Å. The Bi-O bond lengths in I are in the range 2.12–3.16 Å. The Cit ligands act as hexadentate chelating/bridging ligands.

Bismuth nanoparticles have been produced in pores of opal matrices by reducing bismuth salts and oxide compounds with supercritical isopropanol. According to transmission electron microscopy data, the diameter of the SiO 2 spheres in the opal matrices is about 260 nm, and that of the bismuth nanoparticles does not exceed 80 nm.