Untersuchung der Löslichkeitsisothermen im System CuSeO4?H2SeO4?H2O bei 25 und 100°C,der Löslichkeitspolytherme im System CuSeO4?H2O und einiger Eigenschaften der erhaltenen Verbindungen

Investigation of the Isotherms of Solubility in the System CuSeO₄? H₂SeO₄? H₂O at 25 and 100°C, the Polytherm of Solubility in the System CuSeO₄? H₂O, and Some Properties of the Compounds Obtained Existence fields of different compounds from the three-component system CuSeO₄? H₂SeO₄? H₂O were determined. The polytherm of solubility in the system CuSeO₄? H₂O was studied. Data concerning dehydratation of CuSeO₄ · H₂O and thermal dissociation of CuSeO₄ · H₂O are given.     

Zum Ionenaustausch an porösen Gläsern unterschiedlicher Struktur und Textur

Investigation of Phase Equilibria in the Systems CuO? SeO₂? H₂O and Ag₂O? SeO₂? H₂O at 100°C Phase equilibria in the systems CuO? SeO₂? H₂O and Ag₂O? SeO₂? H₂O at 100°C are studied. Crystallization fields and conditions for formation of CuSeO₃ · 2 H₂O, CuSeO₃ · H₂SeO₃, and Ag₂SeO₃ are determined. The thermic dissoziation and the X-ray-patterns of the compounds CuSeO₃ · H₂SeO₃ and CuSeO₃ · SeO₂ obtained for the first time are given.     

Crystal chemistry of MSeO3 and MTeO3 (M = Mg,Mn, Co,Ni, Cu,and Zn)

New selenites and tellurites MgSeO₃, MnSeO₃, CoSeO₃, NiSeO₃, CuSeO₃, MnTeO₃, CoTeO₃, and NiTeO₃ were synthesized under high pressures and temperatures. All the compounds are isomorphous and their crystal system is orthorhombic. Structure analyses were carried out for all the selenites and CoTeO₃. The structure is described as a salt of M²⁺ and SeO₃^2? or TeO₃^2? ions or as a distorted perovskite. In these compounds an Se or Te atom is closely linked to three oxygen atoms to form a flattened trigonal pyramid. The features of this coordination are discussed. At low temperature, magnetic order appears in all the compounds containing iron group ions, among which CuSeO₃ is a ferromagnet with the Curie temperature of 26°K.     

Thermal dehydration and decomposition of copper selenate pentahydrate

Temperature programmed desorption mass spectrometry (TPD-MS) and thermal gravimetry (TG) were utilized for the study of the thermal dehydration and decomposition of copper selenate pentahydrate (CuSeO₄·5H₂O). From the two techniques we suggest that the dehydration is a 3-step process reaching completion at 300 °C. The decomposition process however, is far more complicated consisting of several successive steps occurring between 480 and 900 °C. Initiated with the emission of oxygen, the decomposition of the anhydrous salt continues with SeO₂ emission via several unstable intermediates up to the conversion of the remaining copper monoxide into dicopper monoxide accompanied by oxygen emission.     

Isoelectronic reagents. II. Standard formation enthalpies of phenyl and pfluorophenyl iodine dichlorides

The formation heats ΔH^o_fPhICl₂(c) = 21.7 kJ mol^?1 and ΔH^o_fpFC₆H₄ICl₂(c) = ?173.0 kJ mol^?1 were determined by reaction of iodides with excess chlorine in methyl cyanide. These heats are used to show:(i) that thermal or photo-decompositions of aryl iodine dichlorides are kinetically controlled,(ii) the greater halogenating ability of aryl iodine dichlorides than Ph₃ACl₂ (A = P, As, Sb) compounds, and(iii) the weakening of halogenating ability with phenylation.     

Theoretical predictions on pentaerythritol tetranitrate-based high energy density compounds

A novel family of pentaerythritol tetranitrate (PETN) derivatives based parent PETN skeleton were designed by introducing two energetic groups –NF₂ and –NO₂. Their electronic structure, heats of formation, detonation properties, impact sensitivity, and thermal stability were investigated by using density functional theory. The findings reveal that most of the title compounds have good detonation performance. The –NF₂ group played an important role in improving the densities, heats of detonation, and detonation properties of the designed molecules. The values of h₅₀ for almost all the PETN derivatives are higher than that of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine. An analysis of bond dissociation energy suggests that the N-NO₂ bond tends to be a trigger bond in thermal decomposition. Taking both detonation properties and thermal stabilities into consideration, the three compounds may be selected as potential high-energy-density compounds.     

Calorimetric determination of the thermodynamic properties of the alkali metal salts NaNO3, KNO3, Na2Cr2O7, K2Cr2O7 and their binary eutectic solutions

This work is part of more general project in thermal energy storage by means of the solid—liquid phase transformation. The phase diagrams were checked and slightly modified. A drop calorimeter was used to measure the enthalpies over a small temperature range near the melting points, so enabling the determination of the heats of fusion and the specific heats of the solid and liquid phases over these ranges.For NaNO₃, KNO₃, Na₂Cr₂O₇, K₂Cr₂O₇, NaNO₃KNO₃, NaNO₃Na₂Cr₂O₇, NaNO₃, K₂Cr₂O₇, KNO₃K₂Cr₂O₇ and Na₂Cr₂O₇K₂Cr₂O₇, the enthalpies in the solid and liquid states and the heats of fusion were found to be, respectively, in cal mole^?1; 9300, 12800, 3500 at 581 K; 10300, 12500, 2200 at 611 K; 23600, 29600, 6000 at 625 K; 25000, 34400, 9400 at 666 K; 5700, 8200, 2500 at 495 K; 10300, 13800, 3500 at 535 K; 8700, 11300, 2600 at 495 K; 11100, 13500, 2400 at 537 K; 20300, 23600, 3300 at 573 K. The results for the heats of fusion of the solutions are compared with values obtained by means of simple methods of estimation.     

硝酸碳酰肼合钴、镍、铜含能配合物结构和性质的理论研究

对硝酸三碳酰肼合钴([Co(CHZ)₃](NO₃)₂)、硝酸三碳酰肼合镍([Ni(CHZ)₃](NO₃)₂)和硝酸二碳酰肼合铜([Cu(CHZ)₂(NO₃)₂])进行密度泛函理论计算研究, 获得其稳定分子的几何构型、电子结构、红外光谱以及热化学性质. 研究结果表明, 这三种配合物均表现出六配位八面体结构, 而铜配合物中的硝酸根参与了配位. 自然键轨道分析表明, 配体和金属离子之间存在供体-受体相互作用, 致使配位氨基N—H键上的成键轨道电子发生离域, 进而导致氨基N—H键的电子占据数降低、键长增大、键级减小、伸缩振动频率红移, 这与实测红外光谱变化规律很好地吻合. 标题化合物的金属离子均为＋1氧化态, 金属-氮配位键都是共价键, 而Cu—O配位键是离子键. 通过计算求得理论反应热, 预测这些配合物的合成均为放热反应; 由生成热大小推测标题物的稳定性次序为[Ni(CHZ)₃](NO₃)₂＞[Co(CHZ)₃](NO₃)₂＞[Cu(CHZ)₂(NO₃)₂], 与实测热稳定性次序完全吻合.     

Microcalorimetric Studies of the Surface Reactivity of Pollutant Gas Atmospheres on Supported SnO2 and Ga2O3 Catalysts

The surface properties of gallium oxide and tin dioxide supported on alumina or titania have been studied by adsorption microcalorimetry. The differential heats of adsorption of various pollutant adsorbates such as sulfur dioxide, nitrogen monoxide, nitrogen dioxide and also ammonia were measured on these catalytic surfaces. NH₃, SO₂, NO₂ are strongly adsorbed while NO is only physisorbed. The supported Ga₂O₃ samples show a slight decrease in acidity as probed by ammonia adsorption, compared to alumina or titania. The addition of SnO₂ decreases the number of strong acid sites but creates a few weak and medium strength acid sites on alumina and does not modify the acidity of titania. In all cases, the basicity, probed by SO₂ adsorption, is very strongly affected by the deposition of Ga₂O₃ or SnO₂. The differential heats of NO₂ adsorption remain nearly constant on all samples. The heats of adsorption are discussed as a function of the coverage and of the amount of guest oxide. This revised version was published online in August 2006 with corrections to the Cover Date.     

The heat of wetting of aluminum hydroxyoxide obtained by the thermal activation of hydrargillite

Changes in the volume and surface properties of thermally activated hydrargillite, so-called centrifugal thermal activation (CTA) product (empirical formula Al₂O₃ · 0.85H₂O), during its calcining in air with gradually increasing temperature from 90 to 1100°C were studied. At each stage of calcining, weight loss, phase composition, texture characteristics, and the heat of wetting with water at 25°C were determined. Measurements of the heat of wetting showed that the energy and, therefore, chemical state of the surface changed during thermal treatment. The data obtained were used to calculate the heats of adsorption q _ads of water vapor by CTA samples with different water contents; the range of q _ads variations was 50–250 kJ/mol. The values obtained are compared with literature data.     

硝酸钕和钐的水合物在水中溶解热的测定

本文用补偿式数字量热计测定了六水、四水硝酸钕和六水、五水硝酸钐298.15K时在水中的溶解热,求得了它们的标准生成热、相应的标准脱水焓和晶格能。     

Phase equilibria in the NaCl-NaBr-Na<Subscript>2</Subscript>MoO<Subscript>4</Subscript> system

The binary systems NaBr-Na₂MoO₄ and NaBr-Na₃ClMoO₄ and the ternary system NaCl-NaBr-Na₂MoO₄ have been studied using physicochemical methods (DTA and powder X-ray diffraction). The compositions, melting points, and heats of phase transitions have been determined for three invariant points. The liquidus surface of the ternary system consists of the fields of sodium molybdate, Na₃ClMoO₄, and sodium chloride and bromide solid solutions. The eutectics melt at 531, 612, and 524°C; the respective heats of phase transitions are 149.27, 167.55, and 215.38 J/g.     

Thermal properties of ternary systems: The calculation of the standard enthalpy of solution for compounds in binary mixtures

An equation free of fitting parameters is proposed for calculating the standard heats of solution for compounds in nonaqueous binary mixtures. The parameters of the equation are the standard heats of solution of a compound in the components of the mixed solvent. Nonlinear ΔH ⁰(x) trends are reconstructed for solutions of water in i-PrOH + MeOH and MeCN + MeOH, t-BuOH in MeCN + MeOH, squalane in CHCl₃ + CCl₄ and C₆H₆ + CHCl₃, and hexadecane in MeOH + i-Pr₂O and in mixtures of butyl acetate, ethyl acetate, and 1,4-dioxane with 1-octanol. The standard heats of solutions are calculated for water in alcohol + alcohol, alcohol + aprotic solvent, and aprotic solvent + aprotic solvent mixtures     

三水合希土氯化物(镨、钆)与18－冠－6配合物的热化学研究

制备了ＲＥＣｌ３．３Ｈ２Ｏ（ＲＥ＝Ｐｒ，Ｇｄ）与１８Ｃ６的固态配合物，其化学组成为：ＲＥＣｌ３，１８Ｃ６．３Ｈ２Ｏ。对其进行了ＩＲ，溶解度、ＤＴＧ和ＴＧ分析，推测了热分解机理，测量了２９８．１５Ｋ时１８Ｃ６及两种配合物在无水乙醇中的积分，及ＲＥＣｌ３，３Ｈ２Ｏ在１８Ｃ６－Ｃ２Ｈ２ＯＨ溶液中的溶解配位热效应，依据本文所设计的热化学循环，求得了ＲＥＣｌ３，３Ｈ２Ｏ（ｓ）与１８Ｃ６（ｓ）生成ＲＥＣｌ３，     

Bildung und Stabilität von gasförmigem AsOCl und SbOCl Massenspektrometrische Untersuchungen

Formation and Stability of Gaseous AsOCl and SbOCl. Mass Spectrometric Investigation The reaction of a AsCl₃/O₂ (Sb Cl₃/O₂) with silver at 1300 K leads to the high temperature molecules AsOCl (SbOCl). The heats of formation and ionisation potentials of these molecules have been determined (results see ?Inhaltsübersicht’?). The heats of atomisation and the ionisation potentials of the molecules NOCl, POCl, AsOCl, and SbOCl are discussed.     

The thermodynamic parameters of complex formation between the copper(II) Ion and β-alanine in aqueous solution

The heats of formation of β-alanine complexes with the doubly charged copper(II) ion were determined calorimetrically. The heat effects of interaction of a solution of the amino acid with a solution of copper(II) were measured at 288.15, 298.15, and 308.15 K and ionic strengths of 0.50, 0.75, and 1.00 against the background of KNO₃. The heats of dilution of a solution of copper nitrate with solutions of the background electrolyte were also determined for the introduction of the corresponding corrections. The standard thermodynamic characteristics of complex formation were calculated. The influence of temperature on the thermal effects of complex formation in the β-alanine-copper(II) ions system were considered. The standard enthalpies of formation of CuAla⁺ and CuAla₂ complex particles in aqueous solution were calculated.     

Design of Energetic Materials Based on Asymmetric Oxadiazole

A new family of asymmetric oxadiazole based energetic compounds were designed. Their electronic structures, heats of formation, detonation properties and stabilities were investigated by density functional theory. The results show that all the designed compounds have high positive heats of formation ranging from 115.4 to 2122.2 kJ mol⁻¹. −N− bridge/−N₃ groups played an important role in improving heats of formation while −O− bridge/−NF₂ group made more contributions to the densities of the designed compounds. Detonation properties show that some compounds have equal or higher detonation velocities than RDX, while some other have higher detonation pressures than RDX. All the designed compounds have better impact sensitivities than those of RDX and HMX and meet the criterion of thermal stability. Finally, some of the compounds were screened as the candidates of high energy density compounds with superior detonation properties and stabilities to that of HMX and their electronic properties were investigated.     

Solvation of bivalent transition metal cations. I. Heats of transfer of the metal perchlorates between water,acetonitrile, and dimethylsulfoxide

Heats of solution of Mn(ClO₄)₂·6AN, Fe(ClO₄)₂·6AN, Co(ClO₄)₂·6AN, as well as Ni(ClO₄)₂·6AN, Cu(ClO₄)₂·4AN, and Zn(ClO₄)₂·6AN (AN=acetonitrile) have been determined in water, acetonitrile, and dimethylsulfoxide (DMSO). Coupled with the heats of solution of AN in the respective solvents they give the heats of transfer of the metal perchlorates. Heats of transfer of the cations as well as their heats of solvation are calculated using literature data for the heat of transfer of the perchlorate anion and the heats of hydration of the cations, respectively. The results are discussed in terms of the different contributions to the overall heat effects.     

Gas chromatographic investigation of adsorption equilibria on graphitized thermal carbon black

Summary Retention volumes and heats of adsorption at low surface coverages of graphitized thermal carbon black (GTCB) for C₆–C₁₄ aromatic hydrocarbons have been determined. The dependence of heats of adsorption of these molecules on their structure and the number of carbon atoms in the molecule have been investigated. Substitution in the ring in methylbenzenes is not equivalent to the lengthening of the side-chain in the isomers of n-alkylbenzenes and gives rise to a much greater increase in the retention volumes and heats of adsorption.     

Comparative theoretical studies of substituted bridged bipyridines and their N-oxides

In this work, the experimental synthesized bipyridines azo-bis(2-pyridine),4,4′-dimethyl-3,3′-dinitro-2,2′-azobipyridine, and N,N′-bis(3-nitro-2-pyridinyl)-methane-diamine and a set of designed bipyridines that have similar frameworks but different linkages and substituents were studied theoretically at the B3LYP/6-31G* level of density functional theory. The gas-phase heats of formation were predicted based on the isodesmic reactions, and the condensed-phase heats of formation and heats of sublimation were estimated in the framework of the Politzer approach. The crystal densities have been computed from molecular packing and results show that incorporation of –N=N–, –N=N(O)–, –CH=N–, and –NH–NH– into bipyridines is more favorable than –CH=CH– and –NH–CH₂–NH– for increasing the density. The predicted detonation velocities (D) and detonation pressures (P) indicate that –NH₂, –NO₂, and –NF₂ can enhance the detonation performance, and –NO₂ and –NF₂ are more favorable. Introducing –N=N–, –N=N(O)–, and –NH–NH– bridge groups into bipyridines is also favorable for improving their detonation performance. The oxidation of pyridine N always but that of –N=N– bridge does not always improve the detonation properties. E4–O, the derivative with –N=N– bridge and two –NF₂ substituent groups, has the largest D (9.90 km/s) and P (47.47 GPa). An analysis of the bond dissociation energies shows that all derivatives have good thermal stability.