用稀土多元渗法制备钾稀土钨青铜KxLayWO3的XPS研究

Potassium tungsten bronze K_xLa_yWO₃ (x>0.5 and y<0.01) was synthesized by rare earth co-permeation method using α-K₇[SiMg₃(OH₂)₃W₉O₃₇] as the precursor. Binding energies of La, W, O and C were determined by XPS. From the XPS data, a peak at 34.21 eV indicates that some W⁶⁺ turned into W⁵⁺ by rare earth co-permeation. The binding energies La3d were the same in the surface and inner of the composite, showing that rare earth element La could diffuse into the body of the composite and the compound of K_xLa_yWO₃ was formed at the same time. The binding energies of O1s in K_xLa_yWO₃ surface were 531.4 eV and 532.0 eV, respectively, while peak at 531.4 eV disappeared through etching process. The result implies that the binding energy of 531.4 eV was due to the adsorbent O. In addition, the binding energies of C1s in the surface were 283.5 eV, 285.0 eV and 286.7 eV respectively, while the inner had only one peak at 285.0 eV due to standard C1s. This proves that there was no C in the core.     

Pr对K7MgBW11O39配合物的化学热扩渗及其导电性的研究

Praseodymium Chemistry-Heated Diffused Permeation is used to treat K₇MgBW₁₁O₃₉ for the first time. ICP， IR， XRD， TG-DTA， have been used to characterize K₇MgBW₁₁O₃₉·15H₂O and treated sample， indicating that Pr can be permeated into the body of this sample. The results of AC impedance spectra and DC four-probe show that the value of conductivity is 10⁴ times higher than that of sample before permeation at room temperature. At the range of 301～576K，the conductivity of permeated sample almost keep constant and its thermal stability improved more than 150K， which imply that this material is promising.     

介稳态氧化钨超微粉体的水热合成与光致变色性质研究

Under hydrothermal conditions, the superfine powders of cubic pyrochlore-type of tungsten oxide and hexagonal tungsten bronze were obtained by using Na₂WO₄·2H₂O as the starting material. The products were characterized by XRD, TG, IR, UV and EPMA, respectively. The effects of the pH value, the acid concentration, reaction temperature and time on the structure and particle size of products were investigated in detail. The conditions for the preparation of superfine powders of tungsten oxide were optimized. The pH 2.5～4.5 of the reaction system led to the formation of a pyrochlore phase and pH 0.5～2.0 gave the hexagonal tungsten bronze structure. The photochromism property of the hexagonal tungsten bronze was studied. The results show that pyrochlore and bronze phases are decomposed at 300 ℃ and 450 ℃, respectively. With the increasing of temperature, the structure of the two oxides changes. The pyrochlore-type powder changes completely into triclinic Na₂W₄O₁₃ around 500 ℃, while the bronze phase into a mixture of Na₂W₆O₁₉ and triclinic WO₃ at 550 ℃. The powder of the hexagonal tungsten bronze showed better photochromism property.     

Mo的掺杂对Ce0.8Gd0.2O1.9烧结温度及电性能的影响

Ce_0.8Gd_0.2O_1.9 ceramics were synthesized by sol-gel method and the effect of MoO₃ addition on the sintering temperature, microstructure and electrical properties was examined. The structures and ionic conductivities were characterized by TG/DTA, XRD, field-emission scanning electron microscopy (FE-SEM) and electrochemical impedance spectroscopy (EIS). The results showed that Mo-doped ceramics exhibited viscous flow, which reduces friction of the particles, promots mass diffusivity of the matrix grain boundary mobility, and thus enhances further densification during subsequent sintering. The conductivities of grain boundary and grain interior increased with the decreasing of the grain boundary resistance. With Mo-dopant, the grain interior conductivity increased from 1.27×10^-3 S·cm^-1 to 5.46×10^-3 S·cm^-1, and the grain boundary conductivity increased from 1.02×10^-3 S·cm^-1 to 2.89×10^-3 S·cm^-1 at 600 ℃ for Ce_0.8Gd_0.2O_1.9.     

SrCe0.95Er0.05O3-α固体电解质的导电性

SrCe_0.95Er_0.05O_3-α ceramic of a single orthorhombic phase of perovskite-type SrCeO₃ was prepared by high-temperature solid state reaction. Using the ceramic as solid electrolyte and porous platinum as electrodes, the measurements of conductivities and ionic transport numbers on SrCe_0.95Er_0.05O_3-α ceramic were performed by using electrochemical methods in the temperature range of 600～1 000 ℃ in wet hydrogen, dry air and wet air, respectively. The results indicate that the sample is a pure protonic conductor with a maximal conductivity of 0.01 S·cm^-1 in wet hydrogen, a mixed conductor of oxide-ion and hole in dry air, and a mixed conductor of proton, oxide-ion and hole in wet air.     

一种新的光致变色膜：Na2WO4-PAA-Glycerol体系研究

A method for preparing Na₂WO₄-PAA-Glycerol photochromic films was reported. The film was composed of Na₂WO₄, PAA and Glycerol, which were coated on a glass substrate. The film turned blue in the sun, and bleached to transparent in the darkness. The UV-Visible spectra showed strong absorbance at 300～500 nm, and the ABS changed signifanctly at 500～800 nm. The film showed the best photochromic behavior when n_Na2WO4∶n_PAA is 4%～5%. The mechanism was suggested that after irradiation, poly tunstate produced by Na₂WO₄ and PAA formed the tungsten blues. The tungsten blues were bleached due to oxidation back to poly tunstate by oxygen. The film showed not only an excellent photochromism property with rapid response and good reversibility, but also the simple techniques and good stability.     

三元稀土配合物RE(NTA)2AA的合成、共聚反应性及荧光性能研究

Four new ternary rare earth complexes RE(NTA)₂AA (RE=Sm³⁺， Eu³⁺， Tb³⁺， Dy³⁺) have been synthesized by the reaction of rare earth chloride(RECl₃·6H₂O) with Acrylic Acid (HAA) and 4，4，4-trifluoro-1-(3-pyridyl)-1，3-butanedione(NTA) in alcohol. The copolymerization of the complexes RE(NTA)₂AA (RE=Sm³⁺， Eu³⁺) with methyl methacrylate (MMA) has been studied by 2， 2-azobis-isobutyronitrile as an initiator. Influence of adding Eu(Ⅲ) and 2，2′-bipyridine(bipy) into copolymer Eu(NTA)₂AA-co-MMA on fluorescence property of the Eu copolymer was investigated. The compositions of the complexes and copolymer were characterized by means of elemental analysis and FTIR. The heat decomposing behaviors of the complexes were determined by TG-DTA. The glass transition temperature and molecular weight were obtained by DSC and GPC. The results of fluorescence properties show that the Eu， Sm complexes and Eu copolymer can efficiently emit fluorescence， but the Tb and Dy complexes only emit the fluorescence of β-diketone ligand.     

不同稀土改性SO42-/ZrO2催化剂的结构与性能表征

Solid superacid catalyst SO₄^2-/ZrO₂ was modified by different rare earth compounds and applied to the esterification of acetic acid and n-butanol. The effects of rare earth elements loading on the catalytic properties were studied and the correlation between the structure and properties was investigated by means of XRD, IR, UV, DTA and TG. The results show that the (NH₄)₂Ce(NO₃)₆ modification can enhance catalytic activity more and exhibit better stability than the other two compounds La(NO₃)₃ and Ce(NO₃)₃. Meanwhile,(NH₄)₂Ce(NO₃)₆ modification can restrain the loss of SO₄^2- efficiently. The optimum calcination temperature and molar ratio of Ce(NH)∶Zr for SO₄^2-/ZrO₂ catalyst modified by (NH₄)₂Ce(NO₃)₆ are 450 ℃ and 2, respectively.     

Sm(Ⅲ)(MTB)2配合物与DNA作用的光谱法研究

The interaction between Sm(Ⅲ)(MTB)₂ complex and Herring Sperm DNA has been studied by UV-Vis spectral, Fluorescence spectral in buffer solution of Tris-HCl (pH=7.25) using Neutral Red (NR) as a probe. The intercalation and electrostatic manner are confirmed to be the two major modes for interaction between Sm(Ⅲ)(MTB)₂ complex and Herring Sperm DNA. The balance constant of Sm(Ⅲ)(MTB)₂ rare earth metal complex and Herring Sperm DNA is K=4.10 × 10⁴ L·mol^-1. The results indicate that biological functions of Herring Sperm DNA are changed to a certain extend due to the interaction between Sm(Ⅲ)(MTB)₂ rare earth metal complex and Herring Sperm DNA.     

Nafion? / TiO2复合膜的质子传导性能研究

Nafion^® / TiO₂ composite membranes were prepared by in-situ chemical reaction method using Ti(OC₄H₉)₄ and Nafion^® 117 as raw materials. The membranes were characterized by UV, FTIR-ATR and XRD, respectively. Methanol permeability and water uptake were investigated as a function of TiO₂ contents. The conductivity of the membranes was measured under water vapor pressure (2.644 7 kPa) or in dry atmospheres. The XRD results showed that the titanium dioxide in Nafion^® membranes were crystallized in anatase phase with an average crystaline diameter of 3.0 nm. The water uptake of the composite membranes was larger than that of the pure Nafion^® membrane when the TiO₂ loading was within 14wt%. The methanol permeability of the membrane decreased as the TiO₂ loading increased. The addition of 3wt% TiO₂ to Nafion^® membranes improved the conductivity in dry measurement conditions. The proton conductivity of the composite membrane increased greatly after the hydrothermal treatment at 160 ℃ for 2 hours.     

Phase relations in the K2W2O7-K2WO4-KPO3-Bi2O3 system and structure of K6.5Bi2.5W4P6O34

The phase relations in the cross-section of the K₂W₂O₇-K₂WO₄-KPO₃ containing 15 mol% Bi₂O₃ were undertaken using flux method. Crystallization fields of K_6.5Bi_2.5W₄P₆O₃₄, K₂Bi(PO₄)(WO₄), Bi₂WO₆, KBi(WO₄)₂ and their cocrystallization areas were identified. Novel phase K_6.5Bi_2.5W₄P₆O₃₄ was characterized by single-crystal X-ray diffraction: sp. gr. P−1, a=9.4170(5), b=9.7166(4), c=17.6050(7) Å, α=90.052(5)°, β=103.880(5)° and γ=90.125(5)°. It has a layered structure, which contains {K₇Bi₅W₈P₁₂O₆₈}_∞ layers stacked parallel to ab plane and sheets composed by potassium atoms separating these layers. Sandwich-like {K₇Bi₅W₈P₁₂O₆₈}_∞ layers are assembled from [W₂P₂O₁₃]_∞ and [BiPO₄]_∞ building units, and are penetrated by tunnels with K/Bi atoms inside. FTIR-spectra of K₂Bi(PO₄)(WO₄) and K_6.5Bi_2.5W₄P₆O₃₄ were discussed on the basis of factor group theory.     

Sol-gel synthesis of K3InF6 and structural characterization of K2InC10O10H6F9, K3InC12O14H4F18 and K3InC12O12F18

K₃InF₆ is synthesized by a sol-gel route starting from indium and potassium acetates dissolved in isopropanol in the stoichiometry 1:3, with trifluoroacetic acid as fluorinating agent. The crystal structures of the organic precursors were solved by X-ray diffraction methods on single crystals. Three organic compounds were isolated and identified: K₂InC₁₀O₁₀H₆F₉, K₃InC₁₂O₁₄H₄F₁₈ and K₃InC₁₂O₁₂F₁₈. The first one, deficient in potassium in comparison with the initial stoichiometry, is unstable. In its crystal structure, acetate as well as trifluoroacetate anions are coordinated to the indium atom. The two other precursors are obtained, respectively, by quick and slow evaporation of the solution. They correspond to the final organic compounds, which give K₃InF₆ by decomposition at high temperature. The crystal structure of K₃InC₁₂O₁₄H₄F₁₈ is characterized by complex anions [In(CF₃COO)₄(OH_x)₂]^(5−2x)− and isolated [CF₃COOH_2−x]^(x−1)− molecules with x=2 or 1, surrounded by K⁺ cations. The crystal structure of K₃InC₁₂O₁₂F₁₈ is only constituted by complex anions [In(CF₃COO)₆]³⁻ and K⁺ cations. For all these compounds, potassium cations ensure only the electroneutrality of the structure. IR spectra of K₂InC₁₀O₁₀H₆F₉ and K₃InC₁₂O₁₂F₁₈ were also performed at room temperature on pulverized crystals.     

KCl-KBO2-K2CO3, K2MoO4-KBO2-K2CO3, and K2WO4-KBO2-K2CO3 ternary systems

phase diagrams of KCl-KBO₂-K₂CO₃, K₂MoO₄-KBO₂-K₂CO₃, and K₂WO₄-KBO₂-K₂CO₃ ternary systems were studied by a calculation-experimental method and differential thermal analysis (DTA). The coordinates of ternary eutectics were determined to be E ₁: 622°C, 8.5 mol % KBO₂, 56.5 mol % KCl, and 35 mol % K₂CO₃; E ₂: 710°C, 23 mol % KBO₂, 43 mol % K₂CO₃, and 34 mol % K₂MoO₄; E ₃: 710°C, 23 mol % KBO₂, 43 mol % K₂CO₃, and 34 mol % K₂WO₄. The specific heats of melting of the eutectics were determined.     

Li2SO4-Na2SO4-H2O和Li2SO4- K2SO4-H2O溶液的体积性质

本文用高精度数字式振荡管密度计测定了288K至318K温度范围内Li₂SO₄ + Na₂SO₄ + H₂O和 Li₂SO₄ + K₂SO₄ + H₂O三元体系的密度。混合溶液的离子强度范围从0.1到4.5 mol.kg_–1,混合溶液中Na₂SO₄和K₂SO₄的离子强度分数为0.2,0.4,0.6和0.8。用密度实验值拟合得到了不同温度下Pitzer离子相互作用模型混合参数θ_V和 ψ_V,模型的计算值与实验值的偏差在±0.002 g.cm_–3以内。用Pitzer模型计算了不同离子强度下三元体系的混合体积。     

Solubility in the Na2Cr2O7-(NH4)2Cr2O7-K2Cr2O7-H2O system

Solubility in the Na₂Cr₂O₇-(NH₄)₂Cr₂O₇-K₂Cr₂O₇-H₂O four-component water-salt system at 25, 50, and 75°C was studied for the first time. Phase field boundaries for individual salts and potassium and ammonium dichromate solid solutions, monovariant lines, and invariant points were determined. Experimental data were used to optimize the looped isohydric process of potassium dichromate preparation involving additional salts.     

NaBO2-NaCl-Na2CO3, NaBO2- Na2CO3-NaMoO4, NaBO2- Na2CO3-NaWO4, and NaBO2-NaCl-Na2WO4 ternary systems

The phase diagrams of the NaBO₂-NaCl-Na₂CO₃, NaBO₂-Na₂CO₃-Na₂MoO₄, NaBO₂- Na₂CO₃-Na₂WO₄, and NaBO₂-NaCl-Na₂WO₄ ternary systems were studied by a calculation-experimental method and differential thermal analysis. The coordinates of ternary eutectics were determined: E ₁: 612°C, 16 mol % NaBO₂, 42 mol % NaCl, and 42 mol % Na₂CO₃; E ₂: 568°C, 12 mol % NaBO₂, 28 mol % Na₂CO₃, and 60 mol % Na₂MoO₄; E ₃: 575°C, 12 mol % NaBO₂, 32 mol % Na₂CO₃, and 56 mol % Na₂WO₄; E ₄: 628°C, 8 mol % NaBO₂, 20 mol % NaCl, and 72 mol % Na₂WO₄; and E ₅: 655°C, 9 mol % NaBO₂, 53 mol % NaCl, and 38 mol % Na₂WO₄.     

Extension of the La7Mo7O30 structural type with La7Nb3W4O30 and La7Ta3W4O30 compounds

Two compounds of formula La₇A₃W₄O₃₀ (with A=Nb and Ta) were prepared by solid-state reaction at 1450 and 1490 °C. They crystallize in the rhombohedric space group R-3 (No. 148), with the hexagonal parameters: , and , . The structure of the materials was analyzed from X-ray, neutron and electronic diffraction. These oxides are isostructural of the reduced molybdenum compound La₇Mo₇O₃₀, which are formed of perovskite rod along [111]. An order between (Nb, Ta) and W is observed.     

Theoretical study of polyoxide clusters B20O30, Al20O30, V20O50, Si20O30H20, and Si20O30F20

The structural, electronic, and vibrational characteristics and energies of the isolated polyoxide clusters B₂₀O₃₀, Al₂₀O₃₀, V₂₀O₅₀, Si₂₀O₃₀H₂₀, and Si₂₀O₃₀F₂₀ and their complexes with the H⁻ ion and ammonia complexes Al₂₀O₃₀ · nNH₃ have been calculated by the density functional theory B3LYP method with different basis sets. The computation results show that the symmetric closo structure I _h with oxygen bridges located above the centers of the faces of an empty [M₂₀] dodecahedron is more favorable for V₂₀O₅₀, Si₂₀O₃₀H₂₀, and Si₂₀O₃₀F₂₀. For B₂₀O₃₀, the cage closo isomer is also more favorable than the other isomers, but its structure is severely distorted as compared to a dodecahedron and has a symmetry close to C ₃ . For Al₂₀O₃₀, the I _h structure corresponds to a high-lying local minimum of the potential energy surface. For Al₂₀O₃₀, a set of unusual puckshaped isomers of symmetry C _i , with different numbers of four-coordinate atoms ^IVAl and three-coordinate atoms ^IIIO, was localized; these structures are more than 90 kcal/mol more favorable than the dodecahedron I _h . The most favorable isomer of Al₂₀O₃₀ contains twelve four-coordinate atoms ^IVAl and four five-coordinate atoms ^VAl. The energies of dissociation of the most favorable M₂₀O₃₀ clusters into the M₂O₃ (C _2v ) and M₄O₆ (T _d ) fragments and, in the case of Al₂₀O₃₀, also into the Al₈O₁₂ (O _h ) and Al₁₂O₁₈ (D _3d ) fragments, have been estimated. The conclusion has been drawn that these clusters can, in principle, exist and can be experimentally detected in the isolated state. Analogous calculations have been performed for ammonia complexes Al₂₀O₃₀ · nNH₃ with n varying from 1 to 20. The effect of solvation on the relative stability of the dodecahedral and puckshaped isomers of the Al₂₀O₃₀ cluster is observed. The isomers with ammonia molecules in their first coordination sphere become much closer to one another on the energy scale; however, the dodecahedron remains a considerably less favorable intermediate. Original Russian Text ? O.P. Charkin, N.M. Klimenko, D.O. Charkin, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 4, pp. 624–635.     

Li2O-TiO2-SiO2-P2O5和Li2O-TiO2-Al2O3-P2O5体系锂离子固体电解质的制备及性能研究

一些具有NASICON型网格结构的固体电解质具有高的电导率和好的稳定性,NASICON的意思是Na Super Ionic Conductor[1]。当NaZr2(PO4)3中P5 被Si4 部分取代时便可以得到具有NASICON结构的Na1 xZr2SixP3-xO12体系,其具有高的钠离子电导率。然而有相同结构的Li1 xZr2SixP3-xO12体系的离子电导率却很低,这是因为Li 半径太小,而NASICON三维网格结构的离子通道太大,两者不匹配而使电导率下降[2]。但当LiZr2(PO4)3中Zr4 被离子半径小些的Ti4 取代,所得LiTi2(PO4)3的通道就与Li 半径相匹配,适合于锂离子的迁移,从而使其电导率…     

Structural chemistry of Sr3Cr2WO9, Ca3Cr2WO9, and Ba3Cr2WO9

We have studied the preparation and crystallographic structure of three perovskite-type compounds: Sr₃Cr₂WO₉, cubic, the lattice parameter of which is a = 7.812Å; Ca₃Cr₂WO₉, tetragonal, the lattice parameters of which are a = 5.408 Å and c = 7.635Å; and Ba₃Cr₂WO₉, hexagonal, the lattice parameters of which are a = 5.691 Å and c = 13.957Å. We have compared these three structures and shown the relationship between the dimensions of the alkaline-earth metal and the existence of the different structures.