Structure and Properties of Solid Solutions in the System YBaCuFeO<Subscript>5</Subscript>-YBaCuCoO<Subscript>5</Subscript>

The crystal structure parameters of solid solutions YBaCuFe_{1 − x} Co_xO₅ (0 ≤ x ≤ 1) were determined, and their thermal stability, thermal expansion, conductance, thermoelectromotive force, dielectric properties, and magnetic sensibility were studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 5, 2005, pp. 716–720.Original Russian Text Copyright © 2005 by Chizhova, Klyndyuk, Bashkirov, Petrov, Yanushkevich.     

Behavior of the Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-ZrO<Subscript>2</Subscript> System at High Temperatures

The system Al₂O₃-ZrO₂ at temperatures of up to 2100°C was studied by differential thermal analysis.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 3, 2005, pp. 353–356.Original Russian Text Copyright © 2005 by Kamaev, Archugov, Mikhailov.     

Synthesis and Thermal Decomposition of the Macrocyclic Dinuclear Ni(II) Complex

Crystal of the complex Ni₂L (ClO₄)₂ was obtained by reaction of Ni(ClO₄)₂ and macrocyclic ligand H₂L, where L^2– is the dinucleating macrocycle with two 2,6-di(aminomethyl)-4-methyl phenolate entities combined by the same two lateral chains, –(CH₂)₂–NH–(CH₂)₂–, at the amino nitrogens. The thermal decomposition processes of the title complex were studied in a dynamic atmosphere of dry argon using TG-DTG. The kinetic analysis of the first and second thermal decomposition steps were performed via the TG-DTG curves, and the kinetic parameters were obtained from analysis of the TG-DTG curves with integral and differential methods. The most probable kinetic function was suggested by comparison of the kinetic parameters.This revised version was published online in November 2005 with corrections to the Cover Date.     

Phase Transitions,Thermal Desorption of Gases,and Electroconduction in BaCeO<Subscript>3</Subscript>, a Base for High-Temperature Protonic Conductors

Investigations of phase transitions in barium cerate are carried out by methods of dilatometry and differential scanning calorimetry. Thermal desorption of gases and temperature dependences of electroconduction in dry and humid air are studied. Barium cerate exhibits complex polymorphism, undergoing a number of structural conversions at 300– 1300 K. The peaks in the spectra of thermal desorption of CO₂ and H₂O correlate with variations in the crystal lattice. Structural changes in BaCeO₃ affect activation energies for the carrier transport and the shares of partial conductivities.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 620–626.Original Russian Text Copyright © 2005 by Kuz’min, Gorelov, Vaganov, Korzun, Kazantsev, Aksenova, Khromushin.     

Thermal Behaviour and Decomposition Kinetics for Two Palladium(II) Complexes with 1-aminopyrene and its Derivative

The thermal decomposition studies for two palladium(II) complexes Pd(apyr)₂Cl₂ and Pd(pmpa)Cl₂ (apyr=1–aminopyrene and pmpa=N–(2–pyridylmethylene)–1–pyrenylamine) were carried out in pure nitrogen using TG-DTG techniques. The non-isothermal kinetic parameters for the two complexes were evaluated employing the method suggested by Málek, esták, Koga et al. Based on the above results, thermal behaviour of the complexes were carefully discussed, which showed that not only the parameters value, but also the decomposition pattern and mechanism for complex 1 are different from complex 2.This revised version was published online in November 2005 with corrections to the Cover Date.     

Thermal Reduction of Mechanically Activated Cinnabar (HgS) and Stibnite (Sb2S3)

The reduction of cinnabar (HgS) and stibnite (Sb₂S₃) by hydrogen was investigated. These investigations were performed in the temperature region 636–765 K for cinnabar and in the region 825–954 K for stibnite. It has appeared that the mechanical activation positively affects the thermal reduction of the sulphides. The thermal decomposition of HgS is accompanied by a change in mechanism taking place at 744 K. As to Sb₂S₃, the change in mechanism inthe investigated temperature region was not observed.This revised version was published online in November 2005 with corrections to the Cover Date.     

On the mechanism of formation of intratrack yields of water radiolysis products upon irradiation with fast electrons and positrons: 1. Model formulation

A mathematical model is constructed for the formation of main transient (e _aq ^– , H, OH) and final (H₂, H₃O⁺, OH^–, Ps) radiolytic products formed in tracks of fast electrons and positrons in water and aqueous solutions. The model takes into account the occurrence of reactions of epithermal electrons, along with thermal and hydrated electrons, with a solute; the ambipolar character of diffusion of charged intratrack particles; and new pathways of the formation of hydrogen and positronium due to the appearance of weakly bound adducts of electrons with their scavengers, in addition to the traditional routes.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 3, 2005, pp. 165–170.Original Russian Text Copyright © 2005 by Stepanov, Byakov.     

Formation of Iron-Carbon Nanoparticles behind Shock Waves

An attempt was made to obtain iron-carbon nanoparticles by two-step pyrolysis of Fe(CO)₅- and C₃O₂-containing mixtures behind incident and reflected shock waves in a shock tube. The formation of binary particles was monitored by recording the extinction of He-Ne laser radiation and laser-induced incandescence (LII). The LII method provides particle size estimates if the thermal and optical properties of the constituting material are known. Behind an incident shock wave, at temperatures of 700–1500 K, Fe(CO)₅ decomposes within a short period of time (∼50 µs). The resulting iron atoms combine into particles, which serve as condensation nuclei for carbon vapor resulting from C₃O₂ pyrolysis at 1500–3000 K behind the reflected shock wave. The binary particles thus produced are considerably larger than pure carbon or iron particles. As the mixture temperature behind the reflected shock wave is raised, the diameter of these binary particles decreases.__________Translated from Kinetika i Kataliz, Vol. 46, No. 3, 2005, pp. 333–343.Original Russian Text Copyright © 2005 by Gurentsov, Eremin, Roth, Starke.Based on a report at the VI Russian Conference on Mechanisms of Catalytic Reactions (Moscow, October 1–5, 2002).     

Thermal Analysis of Casein

Case in was analyzed during thermal treatment and pyrolysis. The thermal degradation process of casein was interpreted and thermostability indices, rate, order and activation energy of thermode-structive reaction of casein were determined on the basis of thermogravimetric analysis. The thermodestruction of casein has the characteristics of a first order reaction with activation energy E _a=3.87 kcal mol^–1 (16.2 kJ mol^–1).The pyrolysis of casein was investigated and we determined optimal heating temperature — 550°C and yields of biochar, pitch, pyrolysis water and gases.This revised version was published online in November 2005 with corrections to the Cover Date.     

Complexation processes in KF-SbF<Subscript>3</Subscript>-H<Subscript>2</Subscript>O system studied by calorimetric titration

Complexation in a KF-SbF₃-H₂O system is studied in a range of molar ratios of fluorides KF : SbF₃= (0.1–2) : 1 by calorimetric titration. The equilibrium formation constants of complexes KSb₂F₇, KSbF₄, and K₂SbF₅ (5.8×10⁵±800, 3.3×10⁴±500, and 1.9×10⁶± 950, respectively) and the changes in enthalpy (–31.75± 0.74, –28.15±0.44, and –25.5±0.64 J mol^–1, respectively) and entropy (4±7, –8±5, and –35±9 J mol^–1 K^–1, respectively) are determined. The thermodynamic stability of the antimony(III) fluoride complexes is found to increase on going from KSb₂F₇ to K₂SbF₅.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 168–171.Original Russian Text Copyright © 2005 by Kovaleva, Zemnukhova, Lebedeva, Fedorishcheva.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Investigation of thermal properties of some basalt samples in Egypt

This work aims in studying the temperature dependence of the thermal properties (thermal diffusivity, k, specific heat, C _p and thermal conductivity, ) of some basalt group samples, collected from different regions in the eastern desert of Egypt. The thermal properties of these samples were measured in the temperature range from r.t. to 900 K. The average values of the thermal conductivity of these investigated samples lie in the range from 0.4·10^–3 to 2.01·10^–3 cal cm^–1 s^–1 K^–1. This means that these samples are considered as thermal insulating materials. The thermogravimetric analysis (TG) confirmed that these investigated samples are dry rocks. X-ray fluorescence (XRF) and X-ray diffraction (XRD) confirmed that these rock samples have a crystalline phase, the peaks of XRD have a small change in their location as a result of heat treatment. This behaviour was attributed to the oxidation and firing of some minerals after the heat treatment.This revised version was published online in November 2005 with corrections to the Cover Date.     

Study and Thermodynamic Analysis of the ZrO<Subscript>2</Subscript>-SiO<Subscript>2</Subscript> System

The system ZrO₂-SiO₂ was additionally studied by means of differential thermal analysis. The temperatures of the solid-state decomposition of zircon and the coordinates of the eutectic point were refined. A thermodynamic calculation of the system in terms of the theory of subregular ionic solutions was carried out on the basis of the experimental data obtained.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 207–210.Original Russian Text Copyright © 2005 by Kamaev, Archugov, Mikhailov.     

Application of DSC as a tool for honey floral species characterization and adulteration detection

The thermal behaviour of authentic honeys and sugar syrups (industrial and homemade) was investigated by DSC. To confirm the first previous results concerning the effect of adulteration on the thermal behaviour of authentic honeys, 30 honey samples (Robinia, Lavender, Chestnut and Fir) were analyzed by DSC and their T _g were measured following a suited experimental protocol. The results indicated that this parameter was useful to characterize and to distinguish significantly these varieties between them. Applied to honey samples artificially adulterated with different industrial syrups, DSC showed a detection level of 5–10% depending on the type of syrup. An endothermic phenomenon occurring between 40–90°C during the heating was studied by TMDSC and a new thermal transition similar to a glass-transition was highlighted.This revised version was published online in November 2005 with corrections to the Cover Date.     

Precision Dilatometry of Microemulsions with Anionic Surfactants

Density ρ, isothermal compressibility β_Т, and thermal expansion coefficient α are measured with high accuracy at 15 and 25°C for water-n-octane-sodium dodecyl sulfate-n-pentanol microemulsions with a water/oil weight ratio varying from 0.05 to 4. The internal pressure of the microemulsions is shown to be calculable from the results of dilatometric measurements. The phenomenon of temperature inversion is revealed for the temperature coefficient of internal pressure ΔP _i/ΔT of the microemulsions. The analysis of this coefficient makes it possible to distinguish between three regions of the structural state in the microemulsions and a continuous structural transition in the associated microemulsions.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 4, 2005, pp. 479–484.Original Russian Text Copyright © 2005 by Kartsev, Shtykov, Shtykova.     

Effect of the Metal Salt Anion on Thermal Transformations of Plumbo- and Zincosiloxanes Prepared by the Sol-Gel Method

The effect exerted by the anion of Pb and Zn salts on the thermal evolution of the structure of polymetallosiloxanes formed by base-catalyzed (NH₄OH) hydrolytic polycondensation of ethyl silicate with zinc(II) or lead(II) salts was studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 3, 2005, pp. 380–383.Original Russian Text Copyright © 2005 by Sviderskii, Voronkov, S. Klimenko, V. Klimenko, and Skakun.     

Phase Composition and Charge Transport in Bismuth Molybdates

The study of structural and electrical properties of three pure bismuth molybdate phases, α-Bi₂Mo₃O₁₂, β-Bi₂Mo₂O₉ and γ-Bi₂MoO₆, prepared by the spray drying technique, is described and discussed. The structure of polycrystalline, layered samples investigated by means of XRD and Raman spectroscopy was found to be monoclinic for the α- and β-phases and orthorhombic for the γ-phase. The microstructure of the as-prepared samples was not sufficiently developed under the given conditions of preparation, however, the thermal treatment can improve it. The high polarizability of Bi³⁺ cations with their lone-pair electrons influences the stability of the disordered oxygen sublattice. All as-prepared phases undergo a slight structural change in the temperature region of 280–430°C resulting in a decrease of the electrical conductivity probably due to an order ⇄ disorder transition in the oxygen arrangement during the sample heating. The change of electrical conductivity observed was found to be reversible in the high-temperature region and irreversible in the low-temperature one. The blocking of oxygen transport by the bismuth lone-pair electrons results in an increase of the activation energy and a decrease of the electrical conductivity in the high-temperature region. Relatively high relative dielectric permittivities ɛ_r, 36–52, were observed in dependence on the investigated phase.__________From Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 523–528.Original English Text Copyright © 2005 by Hartmanova, Le, Driessche, Hoste, Kundracik.This article was submitted by the authors in English.     

New ways of synthesis of 1,2-dithiole-3-thione

Two new synthetic approaches to 1,2-dithiole-3-thione are proposed. The title compound is formed by thermolysis of dipropyl polysulfides (n-Pr)₂S_x (x = 3–4) and thermal decomposition of polysulfide dendrimers under reduced pressure. The latter reaction may be recommended for utilization of organochlorine waste products in the manufacture of epichlorohydrin, which are used for the synthesis of dendrimers.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1884–1886.Original Russian Text Copyright © 2004 by Korchevin, Russavskaya, Yakimova, Deryagina.This revised version was published online in April 2005 with a corrected cover date.     

Potentiometric investigations of some catechol derivatives of scandium

The equilibrium reactions of scandium(III) with some triprotic catechol derivatives (H₃L) were studied. The selected ligands that are 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA), 3.4-dihydroxyhydrocinnamic acid (3,4-DHHCA), and 3,4-dihydroxyphenylacetic acid (3,4-DHPA) were investigated in aqueous solution by means of potentiometry in 0.1 M ionic medium at 25°C. The stability constants are reported for the ScL and ScL(H₂L)^– mononuclear complexes. 2,3-DHBA can bind to Sc³⁺ ion strongly and the salicylate mode (COO^–, O^–) is effective over the acidic pH range. But in higher pH range, 3,4-DHBA, 3,4-DHHCA, and 3,4-DHPA act more efficiently through catecholate groups (O^–, O^–).Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 229–233.Original Russian Text Copyright © 2005 by Türkel, Özer.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Computer Simulation of the Absorption of CO<Subscript>2</Subscript> Molecules by Water Cluster: 1. The Stability

The (CO₂)_i(H₂O)₁₀ clusters with the kinetic energy corresponding to a temperature of 233 K is simulated by the molecular dynamics method. The stability of these clusters with respect to thermal, mechanical, and dielectric perturbations, as well as to the absorption of CO₂ molecules, is studied. It is shown that the cluster composed of 10 water molecules remains thermodynamically stable if it captures one or two CO₂ molecules. Clusters are absolutely unstable when 3 ≤ i ≤ 9. A metastable state of clusters is achieved at i > 9.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 3, 2005, pp. 308–314.Original Russian Text Copyright © 2005 by Galashev, Rakhmanova, Chukanov.     

A field-desorption study of thermal stability in potassium pentacyanocobaltates(III)

Field desorption has been applied to research the thermal stability of the compounds K_n[Co(CN)₅X], where X=SO₃ ^2–, CN^–, NO₂ ^–, NO^–, Cl^–, Br^–, I^–, and H₂O. A likely mechanism is proposed for the thermal decomposition. There is a correlation between the tetragonal-distortion parameters and the temperature of onset of destruction for the [Co(CN)₅X]^n– anion.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 21, No. 1, pp. 111–115, January–February, 1985.