Metal Extracts as Precursors for the Production of Metal Powders and Coatings via the Extraction-Pyrolytic Method

The extraction of copper, silver, bismuth, and nickel with carboxylic acids thus providing concentrated metal-containing organic solutions and their crystalline salts has been studied. Micron- and submicron-sized metal powders have been obtained via reduction of these metals carboxylates by heating in benzyl alcohol or ethylene glycol. The synthesis of aspherical silver nanoparticles has been achieved by the reduction of a liquid extract of silver neodecanoate in benzyl alcohol. The possibility of the use of concentrated silver-containing solutions as inks for obtaining of electroconductive images has been demonstrated.     

Synthesis of basic bismuth(III) oxalate by precipitation from nitrate solutions

Conditions were determined in which basic bismuth oxalate of composition BiC₂O₄(OH) can be obtained by direct precipitation upon addition of oxalic acid from nitrate solutions used in production of bismuth compounds. The composition of the compound was confirmed by X-ray phase and chemical analyses, IR and Raman spectroscopy, and thermogravimetry. Electron microscopy was used to examine the effect of the composition of the reaction medium and temperature on the morphology of the product being obtained. It was shown that β-Bi₂O₃ can be obtained in oxidative thermolysis of basic bismuth oxalate, depending on its morphology.     

The kinetics of thermal decomposition of bismuth oxohydroxolaurate

The bismuth salt of lauric (dodecanic) acidBi₆O₄(OH)₄(C₁₁H₂₃COO)₆ was studied earlier. This salt has layer structure (the interlaminardistance=37.50 Å), under heating this liquid-crystalline state has themesomorphic transformation, turns to the amorphous state, decomposes stepwisewith the formation of well-ordered layers of bismuth nanoparticles. DSC-curveswere used for the study of the decomposition kinetics in the area of decompositionwith small mass loss and exothermic effect (423–483 K).     

Synthesis and structure of bismuth(III) oxohydroxocarboxylates

The structure and thermal transformation of bismuth(III) oxohydroxocarboxylates Bi₆O₄(OH)₄(C _n H_{2n − 1}O₂)₆, where (C _n H_{2n − 1}O₂) is a carboxylate ion and n = 2 (2–9, 11), were studied by X-ray powder diffraction, thermogravimetry, IR spectroscopy, and chemical analysis. The conditions of precipitation of bismuth carboxylates from perchlorate solutions were determined. The compounds have a layered structure and undergo the same phase transformations on heating.     

Obtaining Metallic Bismuth in Condensed Media Composed of Formates

Microcrystalline metallic bismuth powders of varied morphology were obtained by reduction of bismuth precursors, basic bismuth formate and bismuth(III) formate in benzyl alcohol, hydrazine hydrate, and sodium borohydride. The methods of X-ray diffraction analysis, scanning electron microscopy, thermogravimetry, and differential scanning calorimetry were used to examine the phase composition and the morphology of the resulting metallic bismuth powders. A dispersion analysis of bismuth samples was made by the method of small-angle scattering of light for a proximate monitoring of the particle size in powders of different fractions. The specific surface area of the metallic bismuth sample was determined by the thermal desorption of argon.     

Precipitation of bismuth(III) oxobromide from bromide media

Abstract—X-ray phase analysis, thermogravimetry, IR spectroscopy, and chemical analysis were used to study bismuth(III) precipitation from nitrate solutions upon addition of aqueous solutions of hydrobromic acid or ammonium bromide, and from bismuth-containing hydrobromic acid solutions. The conditions in which bismuth(III) oxobromide of BiOBr composition is formed were determined and the possibility of obtaining a high-purity product was assessed.     

Interaction of bismuth(III) oxide with formic acid solutions

The interaction of bismuth(III) oxide with formic acid solutions at 22 and 55°C was studied using X-ray powder diffraction, thermogravimetry, electron microscopy, IR spectroscopy, and chemical analysis. Solubility curves were found to comprise two branches due to formates of compositions Bi(COOH)₃ and BiOCOOH forming in the system. Thermal decomposition of bismuth formates is shown to be a promising route for the synthesis of metallic bismuth, as well as of tetragonal (β) and monoclinic (α) bismuth oxides.     

Carbon Monoxide Semiconductor Sensors Based on SnO2-Bi2O3

Gas-sensitive (sensory) properties of bismuth-tin oxide materials, including ceramic films with the Bi₂Sn₂O₇ composition and pyrochlore structure, were considered, as applied to the determination of H₂, CO, and CH₄ in an air mixture.     

Precipitation of Bismuth(III) Oxochloride from Nitrate Solutions

X-ray phase analysis, thermogravimetry, IR spectroscopy, and chemical analysis were used to study precipitation of bismuth from nitrate solutions upon addition of aqueous solutions of hydrochloric acid or ammonium chloride. The conditions in which bismuth(III) oxochloride of BiOCl composition is formed and the possibility of obtaining a high-purity product were determined.     

Thermal decomposition of bismuth stearates

Two bismuth salts, Bi₆O₄(OH)₄(C₁₇H₃₅COO)₆ and Bi₆O₄(OH)₄(C₁₇H₃₅COO)₆·nC₁₇H₃₅COOH, were synthesized. The thermogravimetry under quasi-isothermal conditions denotes the multi-step character of decomposition processes for both compounds. The thermogravimetry under linear heating was used for kinetic studies. Thermogravimetric data (obtained at different rates of linear heating) were processed with 'Netzsch Thermokinetics' computer program. Kinetic parameters were calculated only for the first decomposition step for both salts, the process is described by different nucleation equations (with and without autocatalysis). This revised version was published online in July 2006 with corrections to the Cover Date.