Cu<Subscript>4</Subscript>RbCl<Subscript>3</Subscript>I<Subscript>2</Subscript> solid superionic conductor in thermodynamic study of three-component copper chalcogenides

The Cu-B-Se (B = In, As, Sb, Bi) systems are studied by measurement of EMF for concentration circuits vs. a copper electrode in the temperature range of 300–430 K. A solid superionic Cu₄RbCl₃I₂ conductor is used as an electrolyte. Diagrams of solid-phase equilibriums in the studied systems are constructed. Partial molar functions of alloyed copper are calculated on the basis of the equations of the temperature dependences of EMF. Potential-forming reactions corresponding to the measured EMF values are determined on the basis of the phase diagrams and standard thermodynamic formation functions and standard entropies of ternary compounds are calculated.     

Thermodynamic study of glasses in Ag-As-Se system using EMF method with Ag<Subscript>4</Subscript>RbI<Subscript>5</Subscript> solid electrolyte

The EMF method with Ag₄RbI₅ solid electrolyte was used to study silver solubility in Ag-As-Se glasses on the basis of the cross-sections of (I) Ag-As_0.25Se_0.75, (II) Ag-As_0.33Se_0.67, (III) Ag-As_0.4Se_0.6, and (IV) Ag-As_0.5Se_0.5. It is found that silver solubility reaches 30 and 40 at % in sections (I), (IV) and (II), (III), accordingly. The data of EMF measurements were used as a basis for calculation of partial polar functions of Ag in glasses. The Gibbs-Duhem equations were integrated to calculate thermodynamic functions of silver dissolution in vitreous As _x Se_{1 − x} (x = 0.25; 0.33; 0.4; 0.5), from which the corresponding data for the latter were used to obtain the standard integral thermodynamic functions of the mixing of glasses. The obtained results were compared with the thermodynamic data for crystalline silver selenoarsenites.     

Thermodynamic study of the Ag-As-Se and Ag-S-I systems using the EMF method with a solid Ag<Subscript>4</Subscript>RbI<Subscript>5</Subscript> electrolyte

The EMF method with a solid Ag₄RbI₅ superionic conductor was used to study the Ag-As-Se and Ag-S-I systems in the composition ranges of Ag₂Se-As₂Se₃-Se and Ag₂S-AgI-S, accordingly. Their solid-phase equilibrium diagrams are constructed or specified. The existence of ternary AgAs₃Se₅, AgAsSe₂, Ag₃AsSe₃, Ag₇AsSe₆, Ag₃SI compounds is confirmed. The standard partial and integral thermodynamic formation functions and also standard entropies were calculated for these compounds for the first time.     

Thermodynamic study of Ag<Subscript>8</Subscript>GeSe<Subscript>6</Subscript> by EMF with an Ag<Subscript>4</Subscript>RbI<Subscript>5</Subscript> solid electrolyte

The Ag–Ge–Se system was studied in the range of compositions Ag₂Se–GeSe₂–Se by measuring the EMF of the concentration (relative to the silver electrode) circuits with a solid electrolyte Ag₄RbI₅ in the temperature range 290–430 K. The polymorphic transition temperature of Ag₈GeSe₆ (320 K) was determined and the partial molar functions of silver were calculated for both crystal modifications of this compound based on the EMF measurements. The thermodynamic functions of formation and entropy of both modifications of Ag₈GeSe₆ and the thermodynamic functions of its polymorphic transition were calculated.     

Capacitance characteristics of nanoporous carbon materials in ionistors based on RbAg<Subscript>4</Subscript>I<Subscript>5</Subscript> solid electrolyte

Characteristics of solid-state ionistors developed on the basis of nanoporous carbon synthesized by chlorination of metal carbides are presented. It is shown that the energy storage density in this type of devices reaches 150 J/g when they are operated in the hybrid mode.     

Cyclopropanation of alkynols with the CH<Subscript>2</Subscript>I<Subscript>2</Subscript>-R<Subscript>3</Subscript>Al system

Acetylenic alcohols bearing two or three methylene groups between the triple bond and hydroxy group react with CH₂I₂ in the presence of trialkylalanes to give 1,1,2-tri- and 1,1,2,2-tetrasubstituted cyclopropanes.     

Thermodynamic Properties of AgIn<Subscript>2</Subscript>Te<Subscript>3</Subscript>I and AgIn<Subscript>2</Subscript>Te<Subscript>3</Subscript>Br,Determined by EMF Method

Differential thermal analysis (DTA), X-ray diffraction (XRD), and electromotive force (EMF) are used to triangulate Ag–In–Te–I(Br) systems in the vicinity of compounds AgIn₂Te₃I and AgIn₂Te₃Br. The three-dimensional position of the AgIn₂Te₃I–InTe–Ag₂Te–AgI and AgIn₂Te₃Br–InTe–Ag₃TeBr phase areas with respect to the figurative points of silver is used to create equations of potential-determining chemical reactions. The potential-determining reactions are conducted in (?)C|Ag|Ag₃GeS₃I(Br) glass|D|C(+) electrochemical cells (ECCs), where C stands for inert (graphite) electrodes, Ag and D are ECC electrodes (D denotes alloys of one-, three-, and four-phase areas), and Ag₃GeS₃I and Ag₃GeS₃Br glasses are membranes with purely ionic Ag⁺ conductivity. Linear parts of the temperature dependences of the cell EMFs are used to calculate the standard integral thermodynamic functions of saturated solid solutions based on AgIn₂Te₃I and AgIn₂Te₃Br, and the relative partial thermodynamic functions of silver in the stoichiometric quaternary compounds.     

Electrodeposition of thin Cu<Subscript>2</Subscript>ZnSnS<Subscript>4</Subscript> films

The electrochemical behavior of copper(II), zinc(II), and thiosulfate (S₂O₃ ^2-) ions on the molybdenum electrode in individual 0.2 М sodium sulfate solutions (рН 6.7) and with addition of either 0.1 М tartaric acid (рН 4.6) or 0.1 М citric acid (рН 4.7) is studied. A one-step electrochemical method is developed for the deposition of thin Cu₂ZnSnS₄ films, which is carried out on the molybdenum electrode at a constant potential in sodium sulfate solutions containing tartaric acid. The effect of the concentration of electrolyte components on the chemical composition of Cu₂ZnSnS₄ films is determined. The phase composition is confirmed by the Raman spectroscopy data. The surface morphology of synthesized films is studied by means of scanning-electron and atomic-force microscopes. The photoelectrochemical characteristics of Cu₂ZnSnS₄ films are determined. Samples of these coatings on the Mo electrode are found to be highly photosensitive.     

Whitlockite solid solutions in the Ca<Subscript>3</Subscript>(VO<Subscript>4</Subscript>)<Subscript>2</Subscript>-K<Subscript>3</Subscript>VO<Subscript>4</Subscript>-NdVO<Subscript>4</Subscript> system

Phase equilibria in the Ca₃(VO₄)₂-K₃VO₄-NdVO₄ system have been studied. An extensive calcium orthovanadate-based solid solution was found to form with the boundary compositions as follows: Ca₃(VO₄)₂-Ca₉Nd(VO₄)₇-Ca_9.33K_2.33(VO₄)₇-Ca_7.88K_2.63Nd_0.87(VO₄)₇. The unit cell parameters of the whit-lockite vanadates synthesized increase as the potassium and neodymium contents increase. Phase transitions from the low-temperature β phase to the β′ centrosymmetrical structure in Ca_{9.33 − 5z} K_{2.33 + z} Nd_3z (VO₄)₇ vanadates have been studied dilatometrically. The increase in the β ai β′ transition temperature caused by potassium is interpreted as arising from the filling in of vacant cation positions M(4) and M(6).     

Thermodynamic characteristics of the system NaNO<Subscript>2</Subscript>-NaNO<Subscript>3</Subscript>

The activities and activity coefficients of the components of the system NaNO₂-NaNO₃, obtained from experimental saturated vapor pressures measured at 798, 823, and 848 K, were used to calculate the total and excess partial molar Gibbs energies , , entropies , , and total relative and excess thermodynamic properties G, G ^ex, S, S ^ex of the system.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004, pp. 1747–1749.Original Russian Text Copyright © 2004 by Glazov, Dukhanin, Dkhaibe, Losev.     

Mid-temperature solid oxide fuel cells with thin film ZrO<Subscript>2</Subscript>: Y<Subscript>2</Subscript>O<Subscript>3</Subscript> electrolyte

Data on the mid-temperature solid-oxide fuel cells (SOFC) with thin-film ZrO₂-Y₂O₃ (YSZ) electrolyte are shown. Such a fuel cell comprises a carrying Ni-YSZ anode, a YSZ electrolyte 3–5 μm thick formed by vacuum ion-plasma methods, and a LaSrMnO₃ cathode. It is shown that the use of a combined method of YSZ electrolyte deposition, which involves the magnetron deposition of a 0.5–1.5-μm thick sublayer and its pulse electron-beam processing allows a dense nanostructured electrolyte film to be formed and the SOFC working temperature to be lowered down as the result of a decrease in both the solid electrolyte Ohmic resistance and the Faradaic resistance to charge transfer. SOFC are studied by the methods of voltammentry and impedance spectroscopy. The maximum power density of the SOFC under study is 250 and 600 mW/cm⁻² at temperatures of 650 and 800°C, respectively.     

Thermodynamic study of the Ag-Tl-Se system using the EMF method with AG4RbI5 as a solid electrolyte

Journal of Solid State Electrochemistry - The Ag-Tl-Se ternary system in the composition region Ag2Se-Tl2Se-Se was studied in the temperature range 300–450 K by measuring the electromotive...     

Thermodynamic properties of the system MgO-B<Subscript>2</Subscript>O<Subscript>3</Subscript> melts

Vaporization processes of melts of the system MgO-B₂O₃ at 1640 K were studied by high-temperature mass spectrometry, and thermodynamic properties (activity, chemical potentials of MgO and B₂O₃, and also the corresponding excess values) were determined. Considerable negative deviations from the ideal behavior in the melts of the studied system are observed. The termodynamic properties of the system MgO-B₂O₃ can be calculated within the framework of the lattice theory of associated solutions.     

Chromaticity Characteristics of NH<Subscript>2</Subscript>Hg<Subscript>2</Subscript>I<Subscript>3</Subscript> and I<Subscript>2</Subscript>: Molecular Iodine As a Test Form Alternative to Nessler’s Reagent

The chromaticity characteristics were studied for the product of the reaction of Nessler’s reagent with ammonium ions and for solutions of molecular iodine. These characteristics were used for the determination of the concentration variation step in the construction of the calibration plot in test methods. It was demonstrated that chromaticity measurements can be used for improving the sensitivity of the determination, and iodine solutions can be used in test methods for the construction of the scale simulating NH₂Hg₂I₃.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 7, 2005, pp. 707–710.Original Russian Text Copyright © 2005 by Ivanov, Figurovskaya, Barbalat, Ershova.     

Lithium-conducting solid electrolytes of Li<Subscript>4</Subscript>GeO<Subscript>4</Subscript>-Li<Subscript>3</Subscript>PO<Subscript>4</Subscript> system with additions of zirconium ions

The effect of partial substitution of Zr⁴⁺ ions for Ge4+ ions in highly conducting lithium-cationic solid electrolyte Li_3.75Ge_0.75P_0.25O₄ is studied. It is found that the introduction of zirconium ions considerably raises the conductivity of basic electrolyte in the high-temperature range. For the optimal composition, the conductivity is 2.82 × 10⁻¹ S cm⁻¹ at 400°C and 1.55 S cm⁻¹ at 700°C. Possible reasons for the effects are discussed.     

One-pot synthesis of diphenyl pyrazolylmethylanilines via reductive amination using NaBH<Subscript>4</Subscript>/I<Subscript>2</Subscript> and their antimicrobial screening

Abstract  

Direct reductive amination of 1,3-diphenyl-1H-pyrazole-4-carbaldehyde and 3-(4-methylphenyl)-1-phenyl-1H-pyrazole-4-carbaldehyde with various substituted aromatic amines using NaBH₄ in the presence of I₂ as reducing agent is described. The reaction has been carried out in anhydrous methanol under neutral conditions at room temperature. The structure of newly synthesized diphenyl pyrazolylmethylanilines was established on the basis of IR, ¹H, ¹³C NMR, and mass spectral data. All diphenyl pyrazolylmethylaniline derivatives were tested in vitro for their antifungal and antibacterial activity against different strains of fungi and bacteria. Most of the compound exhibited considerable antifungal activity but poor antibacterial activity against the test strains.     

Thermodynamic properties of melts of the system CaO-B<Subscript>2</Subscript>O<Subscript>3</Subscript>

Activities, chemical potentials, Gibbs energies, and also the corresponding excess values for CaO and B₂O₃ in the homogeneity region of melts of the CaO-V₂O₃ system at 1600 K were determined. These parameters were also calculated in terms of the generalized lattice theory of associated solutions. Considerable negative deviations from the ideal behavior are observed in the melts studied.     

Phase formation in the Ag<Subscript>2</Subscript>MoO<Subscript>4</Subscript>-MgMoO<Subscript>4</Subscript>-Al<Subscript>2</Subscript>(MoO<Subscript>4</Subscript>)<Subscript>3</Subscript> system

The subsolidus region of the Ag₂MoO₄-MgMoO₄-Al₂(MoO₄)₃ ternary salt system has been studied by X-ray phase analysis. The formation of new compounds Ag_{1 ? x} Mg_{1 ? x} Al_{1 + x} (MoO₄)₃ (0 ≤ x ≤ 0.4) and AgMg₃Al(MoO₄)₅ has been determined. The Ag_{1 ? x} Mg_{1 ? x} Al_{1 + x} (MoO₄)₃ variable-composition phase is related to the NASICON type structure (space group R \(\bar 3\) c). AgMg₃Al(MoO₄)₅ is isostructural to sodium magnesium indium molybdate of the same formula unit and crystallizes in triclinic system (space group P \(\bar 1\), Z = 2) with the following unit cell parameters: a = 9.295(7) Å, b = 17.619(2) Å, c = 6.8570(7) Å, α = 87.420(9)°, β = 101.109(9)°, γ = 91.847(9)°. The compounds Ag_{1 ? x} Mg_{1 ? x} Al_{1 + x} (MoO₄)₃ and AgMg₃Al(MoO₄)₅ are thermally stable up to 790 and 820°C, respectively.     

LiF-LiCl-LiVO<Subscript>3</Subscript>-Li<Subscript>2</Subscript>SO<Subscript>4</Subscript>-Li<Subscript>2</Subscript>MoO<Subscript>4</Subscript> system

Phase equilibria in the LiF-LiCl-LiVO₃-Li₂SO₄-Li₂MoO₄ system have been studied by differential thermal analysis. The eutectic composition has been determined as follows (mol %): LiF, 17.4; LiCl, 42.0; LiVO₃, 17.4; Li₂SO₄, 11.6; and Li₂MoO₄, 11.6, with the melting temperature equal to 363°C and the enthalpy of melting equal to (284 ± 7) kJ/kg.