WO<Subscript>3</Subscript> thin film coating from H<Subscript>2</Subscript>O-controlled peroxotungstic acid and its electrochromic properties

We prepared PTA coating solution by hot plate evaporation, N₂ bubbling evaporation, and rotary evaporation. N₂ bubbling and rotary evaporation are very efficient way to synthesize PTA which reduces the synthesis process time to 1/5, compared to hot plate evaporation method. Another strong point is that N₂ bubbling and rotary evaporation make it possible to control excess hydrogen peroxide and water contents in PTA. The PTA formula were WO₃·0.13H₂O₂·10.0H₂O for hot plate method, WO₃·0.16H₂O₂·7.1H₂O for N₂ bubbling method, and WO₃·0.15H₂O₂·3.00H₂O for rotary evaporation method. Thermal analysis and mass spectroscopy analysis show that water is evaporated at around 100 °C and hydrogen peroxide is dissociated at the range of 150 and 250 °C. Amorphous phase of WO₃ thin film prepared from rotary evaporated PTA solution has the best electrochromic property, light transmission difference from 91% at its bleached state and 5.5% colored state, and charge density of 22 mC/cm². It is thought that the control of excess hydrogen peroxide and water contents in PTA is very important to enhance the electrochromic properties of WO₃ thin film.     

Thermodynamic equilibrium study of mineral elements evaporation in O2/CO2 recycle combustion

The facility for the analysis of chemical thermodynamics method (F*A*C*T) based on the Gibbs energy minimization principle, was used to characterize the evaporation of mineral elements of coal in O₂/CO₂ recycle combustion. The effects of atmosphere and temperature on the speciation of mineral species were discussed. The results show that Na(K)Cl(g), FeO(g), and SiO(g) are the dominant gaseous species of the mineral elements. The dominant species of mineral elements in flue gases depend on both the combustion conditions (reducing or oxidizing) and the atmosphere. In O₂/CO₂ mixture combustion, the evaporation rate of mineral elements is much lower than that in air combustion, especially under reducing atmosphere. The total evaporation of mineral elements in O₂/CO₂ atmosphere and air combustion under reducing conditions is 4.46% and 9.65% respectively, up to the temperature of 2400 K. The calculation values are consistent with the experiment values. The decrease in the mineral element evaporation is helpful to suppress the tendency to form fine particle matter and the tendency of initial ash deposition.     

Zur Verdampfung von Indiumtribromid und der Dissoziation In2Br6,g = 2InBr3,g

Evaporation of Indium Tribromide and Dissoziation In₂Br₆,g = 2InBr₃,g The sublimation, evaporation and dissoziation of In₂Br₆ was determined by total pressure measurements in a membran-zero-manometer. The enthalpies and entropies of sublimation, evaporation and dissoziation were derived from the temperature dependence of total pressure and the equilibrium constant. The resulting enthalpy of melting was correlated with the data following from DTA measurements. The domination gaseous species over InBr_x mixtures were determined by mass spectrometry.     

(NH4)2SiF6 evaporation in the presence of SiO2

The kinetics and mechanism of the solid-phase reaction between (NH₄)₂SiF₆ and silica at molar ratios of (0.5–5): 1 were studied. SiO₂ is bound with (NH₄)₂SiF₆ to form volatile NH₄SiOF₃, which abruptly enhances the ammonium hexafluorosilicate evaporation. The activation energy and rate constants of evaporation were calculated for an (NH₄)₂SiF₆ + SiO₂ (2: 1) mixture in the range 220–300°C. The reaction with crystalline SiO₂ has a higher yield than with an amorphous “white soot.” The role of the SiO₂ surface in the formation of the volatile products is discussed. The phase and chemical composition of the sublimates was studied.     

Uranyl dinitrate trihydrate,UO2(NO3)2(H2O)3

The structure of the title compound, which has been synthesized by evaporation at 294 K, consists of centrosymmetric uranyl hexagonal bipyramids that share opposite equatorial edges with two nitrate triangles, resulting in two distinct finite clusters of composition [(UO₂)(H₂O)₂(NO₃)₂]. There are two unique symmetrically independent U^VI positions and two unique nitrate groups.     

Thermische Zersetzung von CuInSe2, LiInSe2 und LiInTe2

The thermal decompositions of CuInSe₂, LiInSe₂ and LiInTe₂ in vacuum at high temperatures were studied by using TG/DTG coupled with mass spectrometry. For CuInSe₂, two steps were found to be significant. Up to 1000 °C Se₂ and In₂Se evaporate, followed later by Cu₂Se. The Li-containing compounds show similar behaviour. However, Li⁺ was already detected during the first step. Obviously, Li₂Se dissociates more readily than Cu₂Se. No Cu⁺ species were detected up to the complete evaporation of CuInSe₂.     

ChemInform Abstract: Crystal Structure and Spectroscopic Studies of LiNH4(H2PO4)2 — A New Solid Acid in the LiH2PO4—NH4H2PO4 System.

LiNH₄(H₂PO₄)₂ is prepared from an equimolar aqueous mixture of NH₄H₂PO₄ and LiH₂PO₄ by slow evaporation at 25 °C.     

Thermodynamic properties and phase equilibria in the system MgO-Al2O3-SiO2 at high temperatures

High-temperature differential mass spectrometry was used to examine evaporation processes and to determine activity of components in the system MgO-Al₂O₃-SiO₂ at 1820 K. The results obtained are in good agreement with the data of thermodynamic calculations.     

Metastable phase equilibria in the systems K2SO4 + K2B4O7 + H2O and KCl + K2B4O7 + H2O at 308.15 K

Experimental studies on the metastable solubilities and physicochemical properties (density and refractive index) in the ternary systems K₂SO₄ + K₂B₄O₇ + H₂O and KCl + K₂B₄O₇ + H₂O at 308.15 K were determined with the method of isothermal evaporation. According to the experimental results, the phase diagrams of the two ternary systems were plotted. In the phase diagrams, there are both two isotherm evaporation curves, one eutectic point corresponding to K₂SO₄ + K₂B₄O₇ · 4H₂O, and KCl + K₂B₄O₇ · 4H₂O, respectively. Both of the ternary systems belong to a simple eutectic type, and neither double salts nor solid solutions formed in the ternary systems. A comparison of the stable and metastable phase diagrams of the ternary systems K₂SO₄ + K₂B₄O₇ + H₂O and KCl + K₂B₄O₇ + H₂O shows that the supersaturated phenomenon of potassium borate tetrahydrate is significant and easier to appear the metastable behavior.     

Effects of evaporation and melting on nonstoichiometry and inhomogeneity of LiInSe<Subscript>2</Subscript> crystals

Evaporation and compositional changes of the liquids above the melting point of LiInSe₂ crystals have been characterized quantitatively by using special techniques of a rapid thermal analysis and differential dissolution. The occurrence of a liquid immiscible region in the Li₂Se-rich side of the Li₂Se-In₂Se₃ diagram and incongruent evaporation with the preferential evaporation of In₂Se₃ rising markedly above boiling point were determined from the peaks on the thermal curves and from precise control over the composition of the vapour and residual solid as a function of temperature. It was shown that both the processes could be the sources of nonstoichiometry and inhomogeneity of the LiInSe₂ crystals.     

Synthesis and crystal structure of nitrosoruthenium aquadiammine complex, [Ru(NO)(NH3)2Cl2(H2O)]Cl·H2O

The reaction between [RuNO(NH₃)₂(NO₂)₂OH] and an excess of 3 M HCl leads to denitration of the starting complex and precipitation of [Ru(NO)(NH₃)₂Cl₃]. Crystals of the tittle complex have been obtained by evaporation of the mother liquor at ambient temperature. The crystal structure of the product has been determined. The linear nitroso group and a water molecule are coordinated in the trans positions, three nitrogen atoms from NO and NH₃ ligands occupy the coordination octahedron face.     

Zur Thermischen Zersetzung von CaOP3F · 2 H2O

On the Thermal Decomposition of CaPO₃F · 2H₂O . The thermal decomposition of CaPO₃F · 2H₂O was investigated by thermogravimetry under inert conditions. A parallel mass spectrometric analysis of gases produced is made. Using an effusion cell a quasi equilibrium evaporation in the nearness of the ion source of the spectrometer is achieved. The results are comparable with the thermogravimetric analysis under normal pressure. During first state of thermal decomposition one mole H₂O is lost. Then the further course is determined by release of HF and POF₃. The several steps of decomposition leading to α-Ca₂P₂O₇ at temperatures above 360° C are discussed.     

Herstellung keramischer Pulver. II. Über die Bildung von Mg2TiO4, MgTiO3 und MgTi2O5 durch Hydrolyse von 2-Ethoxyethylaten

Preparation of Ceramic Powders. II. Mg₂TiO₄, MgTiO₃, and MgTi₂O₅ Formed by Hydrolysis of 2-Ethoxyethylates Solutions of 2-ethoxyethylates of magnesium and titanium in 2-ethoxyethanol submitted to hydrolysis, evaporation and heating of the residue up to 450°C allow to prepare Mg₂TiO₄, MgTiO₃, and MgTi₂O₅ in an amorphous state with smaller than 1% of volatile components. Highly dispersed powders showing an increased sintering activity are obtained as a result of recrystallization. Mg₂TiO₄ is formed as inverse spinel phase in a metastable state.     

Preparation and characterisation of Na2S and ZnSO4 nanoparticles in water/sodium bis(2-ethylhexyl)sulphosuccinate/n-heptane microemulsions

The preparation procedure for nanoparticles of the water-soluble salts Na₂S and ZnSO₄, two commonly used reagents to synthesise ZnS nanoparticles, by evaporation of volatile components of salt-containing water-in-oil microemulsions is described. In suitable conditions, the evaporation leads to the formation of dry salt–surfactant composites and to the formation of Na₂S or ZnSO₄ nanoparticles. It was found that the salt–surfactant composites can be totally redissolved in a dry apolar organic solvent allowing the formation of virtually water-free solutions containing a considerable amount of the water-soluble salts. The presence of nanoparticles in these solutions and in the composites has been proved by small-angle X-ray scattering and transmission electron microscopy, respectively. By mixing these solutions, the solid–solid reaction between Na₂S and ZnSO₄ nanoparticles leading to the formation of very small-sized ZnS nanoparticles has been ascertained by UV spectrophotometry. Received: 09 February 2001 Accepted: 19 March 2001     

Synthesis and structure of a new uranyl selenate complex with 1-butylamine [CH3(CH2)3NH3](H5O2)[(UO2)2(SeO4)3(H2O)]

Crystals of a new uranyl selenate complex [CH₃(CH₂)₃NH₃](H₅O₂)[(UO₂)₂(SeO₄)₃(H₂O)] were obtained by isothermal evaporation at room temperature of its aqueous solution. The crystal structure was determined by the X-ray diffraction analysis. The observed character of the arrangement of organic molecules in the interlayer space confirms the concept of hydrophilic and hydrophobic zones.     

Ln2(ClO4)2(H2I2O10) · 8H2O (Ln = Sm,Gd), a Lanthanide Perchlorate Mesodiperiodate forming a Novel Layer Structure

By slow evaporation of solutions containing Ln(ClO₄)₃ (Ln = Sm, Gd), H₅IO₆ and an excess of HClO₄, crystals of the title compounds could be obtained. Their structures were determined by single‐crystal X‐ray diffraction. The compounds crystallize in the monoclinic crystal system, space group P2₁/c. They contain Ln³⁺ ions, which are coordinated by [H₂I₂O₁₀]^4— anions forming two‐dimensional, cationic networks. These are separated by perchlorate ions, forming a layered structure.     

Strong Attraction of Caffeine to the Mercurous Dumbbell in the Salt [Hg2(Caf)2](ClO4)2(H2O)2

Colourless single crystals of the caffeine adduct of mercurous perchlorate dihydrate, [Hg₂(Caf)₂](ClO₄)₂(H₂O)₂, were grown from aqueous solutions of mercurous perchlorate and caffeine by isothermal evaporation at ambient temperature. The crystal structure (monoclinic, P2₁/n, Z = 4, a = 1628.0(2), b = 780.4(1), c = 2229.6(3) pm, β = 99.84(1)°, R₁(all data) = 0.0894) contains [trans‐Caf‐Hg‐Hg‐Caf]²⁺ cations with a Hg‐Hg distance of 250.88(6) pm, Hg‐N (bond) distances of 214.4(6) and 215.1(6) pm and Hg‐Hg‐N angles of 176.9(2) and 165.1(2)°, respectively. These cations are attached via weak Hg‐O contacts to dimers which are further arranged to leave large channels into which one crystal water molecule is included. The second water molecule and the two perchlorate anions are weakly attracted to one Hg atom.     

Partial Pressure of Saturated Sodium Nitrite Vapor over the System NaNO2-NaNO3

The partial pressure of sodium nitrite was measured in the system NaNO₂-NaNO₃ at temperatures of 798, 823, and 848 K and the logarithm of the NaNO₂ pressure was obtained as a function of inverse temperature. The coefficients A and B of the Clausius-Clapeyron equation and the partial molar heats of evaporation were calculated. The activities and activity coefficients of sodium nitrite were determined for various compositions of the system NaNO₂-NaNO₃.     

Synthesis and crystal structure of tetraethylammonium-μ-trichloro-heptachloro-diaqua-trirhenate(III)-dihydrate,NEt4[Re3Cl10(H2O)2] · 2 H2O

NEt₄[Re₃Cl₁₀(H₂O)₂] · 2 H₂O ( 1 ) was obtained from hydrochloric acid solutions of ReCl₃ and tetraethylammonium chloride, NEt₄Cl, by isothermal evaporation as dark red crystals. 1 crystallizes in the orthorhombic crystal system, space group Pnma, Z = 4, with a = 1838,7(2), b = 1456.9(1), c = 972.08(7) pm, V_m = 391.81(6) cm³ · mol^?l. The crystal structure consists of [Re₃Cl₁₀(H₂O)₂]^? anions that are arranged in the fashion of a hexagonal closest-packing of spheres. These are held together by partially disordered NEt₄⁺ cations and are bound into a hydrogen bonding system with the crystal water.     

MXene/枝状Co/聚偏氟乙烯复合光热膜制备及其界面蒸发性能

使用湿法刻蚀方式将Ti₃AlC₂刻蚀剥离成单/少层Ti₃C₂T_xMXene纳米片,采用电化学还原法制备枝状Co,然后以亲水的聚偏氟乙烯(PVDF)膜为基底通过真空抽滤制备Ti₃C₂T_x/枝状Co/PVDF复合光热膜。对复合材料的结构和形貌进行表征,研究了复合光热膜的光吸收性能和界面蒸发性能。结果表明,在模拟1个太阳光照下(光照强度为1kW·m^-2),Ti₃C₂T_x/枝状Co/PVDF复合光热膜的光吸收率达到95.3%,纯水蒸发速率达到1.78kg·m^-2·h^-1,界面蒸发效率高达97.5%。此外,还测试了在模拟海水中的界面蒸发性能,蒸发冷凝得到的水达到世界卫生组织(WHO)和美国环境保护署(EPA)饮用水标准,蒸发速率达到1.61kg·m^-2·h^-1,循环5次后稳定在1.59kg·m^-2·h^-1。