Thermodynamic functions and structure of gallium + tellurium liquid alloys

In the frame of our systematic investigation on strongly interacting alloy systems, we have measured the molar enthalpy of formation, ΔH_f, of liquid Ga + Te alloy at 1200 and 1238 K by direct reaction calorimetry, using a Calvet microcalorimeter. The enthalpy of formation, with reference to the pure liquid components, is negative over the whole range of mole fractions x and has a minimum at x_Te ≈ 0.6. ΔH_f(l, x_Te = 0.61, 1200 K) = ?(38.8 ± 0.8) kJ mol^?1. This is evidence for strong chemical interactions in the liquid phase with formation of Ga₂Te₃ clusters. No significant difference was noted between the enthalpies at 1200 and 1238 K. Comparison of the molar integral enthalpies and entropies of formation of liquid Me_0.4^IIITe_0.6 alloys (Me^III  Al, Ga, In, and Tl) shows that the stability of the Me₂Te₃ clusters decreases in the series Al > Ga > In > Tl.     

An examination of the product-catalyzed reaction of trimethylgallium with arsine

The reaction of (CH₃)₃Ga with AsH₃ at 203°C and 259°C has been examined over the product surfaces which were (CH₃)₃- GaAsH₃-x where the average values of x were 1.1 and 2.2 203°C and 259°C respectively. The surface reaction (catalyzed by the product surface) forming (CH₃)₂GaAsH₂ occurred on the surface between adsorbed molecules of (CH₃)₃Ga and ASH₃. The surface coverages of the reactants (gas pressures between 18 and 36 mmHg) were clearly less than monomolecular and for AsH₃ possibly as low as 0.01. For AsH₃ at a surface coverage of 0.12, adsorption data were consistent with AsH ₃ bound to the surface as a mobile film. The formation of GaAs via CH₄ elimination from (CH₃)₂GaAsH₂ or CH₃GaAsH was hindered by deposition of films of (CH₃)₃-x GaAsH₃-x even at 420°C. This was most significant for formation of GaAs (or even CH₃GaAsH) from (CH₃)₂-GaAsH₂ formed at 203°C and then heated at 420°C. The product surfaces also served as a catalyst for decomposition of AsH₃ to form H₂ and decomposition of (CH₃)₃Ga to form CH₄.     

Features of Joint Thermolysis of Organometallic Compounds of Group III and V Elements

The kinetic data on thermolysis of equimolar gaseous mixtures of organometallic compounds of Group III and V elements show that the thermal stability of the mixture differs from that of the components taken separately, which is mainly due to complexation between the mixture components. The complex is a kinetically active species. The rate of joint thermolysis of the organometallic compounds grows as the number of hydride atoms at the Group V element increases in the order AsMe3 < t-BuPH₂ < AsH₃. The stability of the complexes formed by organometallic compounds of Group III and V elements decreases in the same order. Joint thermolysis of Me₃Ga and AsH₃ yields a solid oligomer Me₂GaAs(H)Ga(Me)AsH₂. The complicated pattern of decomposition of a mixture of trimethylaluminum with various electron donors is due to participation in the pyrolysis of two trimethylaluminum species: monomeric and dimeric. In decomposition of pure trimethylaluminum or its mixtures with organometallic compounds of Group V elements or with ether, solid pyrolysis products deposited on the vessel walls catalyzed further transformations of the mixture components.     

Studien zur Reaktion von [Me2AlP(SiMe3)2]2 mit basenstabilisierten Organogalliumchloriden und ‐hydriden

Investigations on the Reactivity of [Me₂AlP(SiMe₃)₂]₂ with Base‐stabilized Organogalliumhalides and ‐hydrides [Me₂AlP(SiMe₃)₂]₂ ( 1 ) reacts with dmap?Ga(Cl)Me₂, dmap?Ga(Me)Cl₂, dmap?GaCl₃ and dmap?Ga(H)Me₂ with Al‐P bond cleavage and subsequent formation of heterocyclic [Me₂GaP(SiMe₃)₂]₂ ( 2 ) as well as dmap?AlMe_xCl_3?x (x = 3 8 ; 2 3 ; 1 4 ; 0 5 ). The reaction between equimolar amounts of dmap?Al(Me₂)P(SiMe₃)₂ and dmap?Ga(t‐Bu₂)Cl yield dmap?Ga(t‐Bu₂)P(SiMe₃)₂ ( 6 ) and dmap?AlMe₂Cl ( 3 ). 2 – 8 were characterized by NMR spectroscopy, 2 and 6 also by single crystal X‐ray diffraction.     

离子液体电沉积CuIn_xGa_(1-x)Se_2薄膜(英文)

采用循环伏安法(CV)对离子液体Reline中三元CuCl2+InCl3+SeCl4体系和四元CuCl2+InCl3+GaCl3+SeCl4体系的电化学行为进行了研究。研究表明,In3+并入三元CIS(Cu-In-Se)薄膜体系和Ga3+并入四元CIGS(Cu-In-Ga-Se)薄膜体系均有两种途径:一是发生共沉积,二是直接还原。利用电感耦合等离子体发射光谱(ICP)和扫描电镜(SEM)对沉积电势、镀液温度和主盐浓度对CIGS薄膜组成、镀层表面形貌的影响进行了测试,结果表明通过工艺参数的选择可以控制Ga/(Ga+In)和CIGS薄膜组成并得到化学计量比为Cu1.00In0.78Ga0.27Se2.13的薄膜。     

An ab initio molecular orbital study of the trimethylgallium-arsine adduct: (CH3)3Ga:AsH3

The structure, harmonic frequencies, and binding energy of the trimethylgallium-arsine adduct, (CH₃)₃Ga: AsH₃, have been computed using ab initio molecular orbital methods, and, where possible, compared with experimental results. The structures and frequencies of the precursors trimethylgallium and arsine are perturbed to only a small extent upon adduct formation. The binding energy of (CH₃)₃Ga: AsH₃ is found to be 5.2 kcal/mol lower than that for H₃Ga:AsH₃ at the MP2/HUZSP^*//RHF/HUZSP^* level of computation.     

Oxidation of γ-stannyl sulfides by monochloramine CB and hydrogen peroxide

The first γ-trimethylstannyl sulfimide, Me³Sn(CH₂)₃S(=NSO₂Ar)C₅H₁₁-n, was synthesized by oxidative imination of Me₃Sn(CH₂)₃SC₅H₁₁-n with ArSO₂(Na)Cl (Ar=C₆H₄Cl-4). Oxidation of γ-trimethylstannyl sulfimide by an alkaline solution of H₂O₂ gave γ-trimethylstannyl sulfoximide, Me₃Sn(CH₂)₃S(O)(=NSO₂Ar)C₅H₁₁-n, and γ-trimethylstannyl sulfone, Me₃Sn(CH₂)₃SO₂C₅H₁₁-n, the latter compound resulting from hydrolysis of the arylsulfimide group. Oxidation of stannyl sulfide by hydrogen peroxide yielded γ-trimethylstannyl sulfoxide, Me₃Sn(CH₂)₃S(O)C₅H₁₁-n (under mild conditions) or γ-trimethylstannyl sulfone (under more severe conditions). Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 371–374, February, 1997.     

离子液体电沉积CuInxGa1-xSe2薄膜

采用循环伏安法(CV)对离子液体Reline中三元CuCl₂+InCl₃+SeCl₄体系和四元CuCl₂+InCl₃+GaCl₃+SeCl₄体系的电化学行为进行了研究。研究表明,In³⁺并入三元CIS(Cu-In-Se)薄膜体系和Ga³⁺并入四元CIGS(Cu-In-Ga-Se)薄膜体系均有两种途径：一是发生共沉积,二是直接还原。利用电感耦合等离子体发射光谱(ICP)和扫描电镜(SEM)对沉积电势、镀液温度和主盐浓度对CIGS薄膜组成、镀层表面形貌的影响进行了测试,结果表明通过工艺参数的选择可以控制Ga/(Ga+In)和CIGS薄膜组成并得到化学计量比为Cu_1.00In_0.78Ga_0.27Se_2.13的薄膜。     

Reactions of methylniobium(V) and methyltantalum(V) chlorides with ketones

The chlorides Me_xMCl_5-x, M = Nb, Ta, x = 1, 2, 3 react with carbodiimides RNCNR (R = isopropyl, cyclohexyl, p-tolyl) to give products of the types MCl₄[NR-C(Me)=NR], MeMCl₃[NR-C(Me)=NR], MCl₃[NR-C(Me)=NR]₂, Me₂MCl₂[NR-C(Me)=NR], MeMCl₂[NR-C(Me)=NR]₂, which cóntain bidentate acetamidine groups arising from insertion of the carbodiimide into the metal-carbon bond. The products have been characterised by elemental analysis IR and proton NMR spectra.     

Surface Chemistry of Ga(CH3)3 on Pd(111) and Effect of Pre-covered H and O

The adsorption and decomposition of trimethylgallium (Ga(CH₃)₃, TMG) on Pd(111) and the effect of pre-covered H and O were studied by temperature programmed desorption spectroscopy and X-ray photoelectron spectroscopy. TMG adsorbs dissociatively at 140 K and the surface is covered by a mixture of Ga(CH₃)_x (x=1, 2 or 3) and CHx(a) (x=1, 2 or 3) species. During the heating process, the decomposition of Ga(CH₃)₃ on clean Pd(111) follows a progressive Ga-C bond cleavage process with CH₄ and H₂ as the desorption products. The desorption of Ga-containing molecules (probably GaCH₃) is also identi ed in the temperature range of 275-325 K. At higher annealing temperature, carbon deposits and metallic Ga are left on the surface and start to di use into the bulk of the substrate. The presence of precovered H(a) and O(a) has a signi cant effect on the adsorption and decomposition behavior of TMG. When the surface is pre-covered by saturated H₂, CH₄, and H₂ desorptions are mainly observed at 315 K, which is ascribed to the dissociation of GaCH₃ intermediate. In the case of O-precovered surface, the dissociation mostly occurs at 258 K, of which a Pd-O-Ga(CH₃)₂ structure is assumed to be the precusor. The presented results may provide some insights into the mechanism of surface reaction during the lm deposition by using trimethylgallium as precursor.     

Origin and Location of Electrons and Protons during the Formation of Intermetalloid Clusters [Sm@Ga3−xH3−2xBi10+x]3− (x=0, 1)

Reaction of [GaBi₃]^2? with [Sm(C₅Me₄H)₃] yielded the first protonated ternary intermetalloid clusters [Sm@Ga_3?xH_3?2xBi_10+x]^3? ( 1 ; x=0,1). The presence of the Ga? H bonds and the transfer of electrons and protons during the formation of 1 were elucidated by a combination of experimental and quantum chemical methods, thereby rationalizing the role of the solvent ethane‐1,2‐diamine as a Brønsted acid. As an organic by‐product, we observed the previously unknown octamethylfulvene ( 2 ) upon C? C coupling of (C₅Me₄H)^?.     

Electrophysical properties of materials based on BaGdCo2O5 + δ

The phase composition, linear thermal expansion coefficient, electroconductivity (in the temperature interval 600–900°C and partial pressures of oxygen 10⁻⁵–0.21 atm) of solid-oxide materials based on gadolinium-barium cobaltite doped with 3d-elements BaGdCo_{2 − x} Me _x O_{5 + δ}, Me = Cu, Fe; x = 0.0, 0.2, …, 2.0 were investigated. The homogeneity regions of samples were established by means of X-ray phase analysis. It was shown that the linear thermal expansion coefficient of cobaltite decreases with an increase in the copper or iron concentration. It was established that the electroconductivity of BaGdCo_{2 − x} Me _x O_{5 + δ} decreases with an increase in x. We concluded that upon a decrease in p(O₂), the electroconductivity of samples first decreases and then reaches a horizontal plateau.     

Catenated Gallium Compounds Supported by a<Emphasis Type="Italic"> Tris</Emphasis>(pyrazolyl)hydroborato Ligand

[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]M (M = K, Tl) reacts with “GaI” to give a series of compounds that feature Ga–Ga bonds, namely [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaI₃, [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]GaGaI₂GaI₂( \textHpz^\textMe₂ {\text{Hpz}}^{{{\text{Me}}_{2} }} ) and [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga(GaI₂)₂Ga[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ], in addition to the cationic, mononuclear Ga(III) complex {[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]₂Ga}⁺. Likewise, [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]M (M = K, Tl) reacts with (HGaCl₂) ₂ and Ga[GaCl₄] to give [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaCl₃, {[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]₂Ga}[GaCl₄], and {[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]GaGa[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]}[GaCl₄]₂. The adduct [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→B(C₆F₅)₃ may be obtained via treatment of [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]K with “GaI” followed by addition of B(C₆F₅)₃. Comparison of the deviation from planarity of the GaY₃ ligands in [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaY₃ (Y = Cl, I) and [ \textTm^{\textBu\textt} {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga→GaY₃, as evaluated by the sum of the Y–Ga–Y bond angles, Σ(Y–Ga–Y), indicates that the [ \textTm^{\textBu\textt} {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga moiety is a marginally better donor than [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga. In contrast, the displacement from planarity for the B(C₆F₅)₃ ligand of [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→B(C₆F₅)₃ is greater than that of [ \textTm^{\textBu\textt} {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga→B(C₆F₅)₃, an observation that is interpreted in terms of interligand steric interactions in the former complex compressing the C–B–C bond angles.     

Untersuchungen an zeolithischen Heptagermanaten mit Hilfe der Kernresonanzmethode

Zusammenfassung Zeolithische Heptagermanate der FormelMe ₃HGe₇O₁₆ ·x H₂O (Me=Li, K, Rb, Cs, Tl) mit verschiedenem Wassergehalt (x=0–6) wurden röntgenographisch, thermogravimetrisch und mit Hilfe von Kernresonanzmessungen bei verschiedenen Temperaturen untersucht. Während bei Raumtemp. der Großteil der Wassermoleküle beweglich ist, frieren diese Bewegungen bei Erniedrigung der Temperatur allmählich ein. Außerdem zeigen die Resonanzen einen Anteil, der isolierten Protonen zuzuordnen ist.

---

NMR studies on zeolitic heptagermanates

Zeolitic heptagermanates with compositionMe ₃HGe₇O₁₆ ·x H₂O (Me=Li, K, Rb, Cs, Tl;x=0–6) were studied by means of X-ray, thermogravimetric and NMR measurements at various temperatures. At room temperature the largest part of the water molecules is mobile. The motion of these molecules is frozen in continuously by lowering the temperature. The resonances do also exhibit a part which can be correlated to the presence of isolated protons.

---

---

Mit 8 Abbildungen     

Thermodynamic investigation of several natural polyols (II)

The low-temperature heat capacity C _p,m of sorbitol was precisely measured in the temperature range from 80 to 390 K by means of a small sample automated adiabatic calorimeter. A solid-liquid phase transition was found at T=369.157 K from the experimental C _p-T curve. The dependence of heat capacity on the temperature was fitted to the following polynomial equations with least square method. In the temperature range of 80 to 355 K, C _p,m/J K⁻¹ mol⁻¹=170.17+157.75x+128.03x ²-146.44x ³-335.66x ⁴+177.71x ⁵+306.15x ⁶, x= [(T/K)−217.5]/137.5. In the temperature range of 375 to 390 K, C _p,m/J K⁻¹ mol⁻¹=518.13+3.2819x, x=[(T/K)-382.5]/7.5. The molar enthalpy and entropy of this transition were determined to be 30.35±0.15 kJ mol⁻¹ and 82.22±0.41 J K⁻¹ mol⁻¹ respectively. The thermodynamic functions [H _T-H _298.15] and [S _T-S 298.15], were derived from the heat capacity data in the temperature range of 80 to 390 K with an interval of 5 K. DSC and TG measurements were performed to study the thermostability of the compound. The results were in agreement with those obtained from heat capacity measurements.     

A study of YBa2(Cu1?xMex)3O6 + δ (Me = Al, Co, Fe) electrophysical and electrochemical properties

The structure, thermal expansion coefficient, and electroconductivity of YBa₂(Cu_1−x Al _x )₃O_6+δ (x = 0.0–0.9) were studied at 20 to 900°C in air. The most conducting compositions of YBa₂(Cu_1−x Me _x )₃O_6+δ (Me = Al, Co, Fe) were determined. The electrochemical activity of electrodes with the most conducting compositions of YBa₂(Cu_1−x Me _x )₃O_6+δ (Me = Al, Co, Fe) was studied in a wide polarization range in the contact with 0.9ZrO₂ + 0.1Y₂O₃ solid electrolyte in air at the temperatures of 700 to 900°C. Original Russian Text ? V.K. Gil’derman, I.D. Remez, 2009, published in Elektrokhimiya, 2009, Vol. 45, No. 5, pp. 612–615. Published by report at IX Conference “Fundamental Problems of Solid State Ionics”, Chernogolovka, 2008.     

Structure and Magnetism of Pr1−xSrxFeO3−δ

Crystal structure, redox, and magnetic properties for the Pr_1−xSr_xFeO_3−δ solid-solution phase have been studied. Oxidized samples (prepared in air at 900°C) crystallize in the GdFeO₃-type structure for 0≤x≤0.80, and probably in the Sr₈Fe₈O₂₃-type (unpublished) structure for x=0.90. Reduced samples (containing virtually only Fe³⁺) crystallize as the perovskite aristotype for x=0.50 and 0.67 with randomly distributed vacancies. The Fe⁴⁺ content increases linearly in the oxidized samples up to x≈0.70, whereupon it stabilizes at around 55%. Antiferromagnetic ordering of the G type is observed for oxidized samples (0≤x≤0.90) which show decreasing Néel temperature and ordered magnetic moment with increasing x, while the Néel temperature is nearly constant at 700 K for reduced samples. Electronic transitions for iron from an average-valence state via charge-separated to disproportionated states are proposed from anomalies in magnetic susceptibility curves in the temperature ranges 500–600 K and 150–185 K.     

Peculiarities of interaction of H+, Me3C+, and Me3Si+ ions with multifunctional molecules in the gas phase

Peculiarities of interaction of H⁺, Me₃C⁺, and Me₃Si⁺ ions with functional groups of molecules in the gas phase have been studied. Proton tends to form chelates with virtually all of the functional groups studied, whereas Me₃Si⁺ ions exhibit no capacity for chelation. Using isomeric xylenes as examples it was shown that Me₃Si⁺ ions (unlike Me₃C⁺ ions) experience virtually no steric hindrance when they react with nucleophilic centers. Effects of functional groups present in molecules of nitriles on the generation of [M+Me₃C]⁺ adducts in the gas phase and the Ritter reaction in solution were estimated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1767–1773, September, 1995.This work was carried out with financial support from the International Science Foundation (Grant MA7 000) and the Russian Foundation for Basic Research (Project No. 93-03-18033).     

Review of the thermodynamic and transport properties of EuBr<Subscript>2</Subscript>–RbBr binary system

Differential Scanning Calorimetry was used to study phase equilibrium in EuBr₂–RbBr binary system. It was established that this system includes two eutectics and three stoichiometric compounds. First of them, Rb₂EuBr₄, decomposes peritectically at 778 K. Second one, RbEuBr₃, undergoes the solid–solid phase transition at 732 K and melts incongruently at 852 K. Third compound, RbEu₂Br₅, melts congruently at 888 K. The composition and temperature values of eutectics were determined as x(EuBr₂) = 0.316; T _eut = 776 K and x(EuBr₂) = 0.797; T _eut = 859 K. Mixing enthalpy was measured by direct calorimetry on the whole composition range. The minimum of the mixing enthalpy occurs around the composition x(EuBr₂) ≈ 0.4. The electrical conductivity of liquid mixtures was also investigated over the whole composition range and measured down to temperatures below solidification. The specific conductance (liquid phase) plotted against the mole fraction of EuBr₂ shows a broad minimum at x(EuBr₂) ~ 0.6. The activation energy for conductivity changes with temperature. Results obtained are discussed in terms of possible complex formation.     

Reaktionen einiger Methylmetallhalogenide des Aluminiums,Galliums und Indiums mit Hexamethyldisilazan

Reactions of some Methylmetal Halides of Aluminium, Gallium, and Indium with Hexamethyldisilazane MeAlCl₂ or MeGaBr₂, and bis(trimethylsilyl)amine form the dimeric, mixed-substituted ring molecules (Me(Hal)M^III–N(H)SiMe₃)₂ and one equivalent Me₃SiHal. The NMR (¹H, ¹³C, ²⁹Si) and vibrational spectra (IR, Raman) are measured and the X-ray structure analysis of the compound with M^III = Al and Hal = Cl, has been done as well. Me₂AlCl with an excess of HN(SiMe₃)₂ forms the expected amide (Me₂Al–N(H)SiMe₃)₂, the homologue Me₂GaCl with HMDS, however, gives at 50–55 °C only the cyclic (1 : 1) adduct (Me₂Ga–N(H)SiMe₃) · (Me₂GaCl). This complex crystallizes in the space group Cmc2₁, the unit cell consists of four binucleate molecules with folded Ga–N–Ga–Cl-ring skeletons.