981 resultados para Orthovanadates(V) potassium


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K4H2CoW12O40. 2Ti02 . 9H(2)O crystallizes from an aqueous solution of Na2WO4, Co(OAc)(2) and Ti(SO4)(2). The compound has very similar i.r. and u.v. spectra to those of [CoW12O40](6-) and [CoW11TiO40](8-) but its polarographic behaviour is different from that of [CoW11TiO40](8-) and exhibits only reduction of tungsten(VI). A single crystal structural analysis indicates that this compound consists of the heteropolyanion [CoW12O40](6-), titanium-oxygen chain, potassium ions and water molecules.

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Reaction of the half-sandwich rhenium(v) complexes [Re-Cl-4(C(5)Me(5))] or [Re(O)Cl-2(C(5)Me(5))] with H2S in chloroform in the presence of pyridine leads to the chiral dithiolato complex [ReO((S)(SCH2)C(5)Me(4))(C(5)Me(5))] 1.

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With XRD, R-T, and ac chi measurements a comparative study on the doping effects of 3d elements in Bi(1.5)Pb(0.2)Sr(2)Ca(2)Cu(2.8)M(0.2)O(y) (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, or Zn) has been carried out. The effects of the former five members are significantly different, both on phase formed and on T-c, from the latter four. It seems that the effect on phase stabilization correlates with the valency of the doped cation. In connection with the instability of the 2223 phase, the correlation has been discussed.

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多组分氧化物Ag-Bi-V-Mo-O催化作用的光电子能谱研究宋伟,李静,窦伯生(中国科学院长春应用化学研究所长春130022)关键词 钼钒酸铋,助剂Ag,XPS,Ar~+刻蚀,氧化还原对于烃类选择氧化反应中复合氧化物的催化作用,普遍认为是Redox机...

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丙烷氧化反应中多组分氧化物Bi-V-Mo-O催化作用的红外光谱研究李静,宋伟,窦伯生(中国科学院长春应用化学研究所长春130022)关键词钼钒酸铋,丙烷,选择氧化,催化作用机理,红外光谱迄今对于含有钼、铋复合氧化物催化剂的活性中心和作用机理存在不同看...

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The variation in molecule adsorption mode on pretreated highly oriented pyrolytic graphite electrodes, modified with the title complex K10H3[Dy(SiMo11O39)(2)] by cyclic voltammetry in the title complex solution, was observed in situ by electrochemical scanning tunnelling microscopy (ECSTM) with molecular resolution in sodium sulphate solution. According to the ECSTM images and the known molecular structure we conclude that the adsorption mode of the title complex modified electrode changed during potential cycling from ''vertical'' to ''inclined'' and then ''horizontal'' or ''flat'' mode, i.e. the title complex adsorbed on the surface of electrode by one ligand of the complex at first, then began to incline and was finally adsorbed by two ligands of the complex. This result indicates that the adsorption mode on the modified electrode surface changed during potential cycling in the sulphate solution and a much more stable molecular layer was formed. The change in adlattice of adsorbates on the modified electrode surface from hexagonal to rectangular was also observed by ECSTM. A plausible model was given to explain this process.

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A new series of fully aromatic thermotropic liquid crystalline copolyesters were synthesized by thermal polycondensation of p-hydroxybenzoic acid (PHB), terephthalic acid (TPA), resorcinol (RES) and bis (4-hydroxyphenyl) methanone (BHP). The DSC traces of copolyesters exhibited two or three endotherms, the low temperature endotherm(Tm) of which indicated the transition from solid state to anisotropic phase. Observation under polarizing microscope and WAXD measurements suggested that the LC-phase formed immediately above Tm had a nematic character.

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X-ray diffraction and electrical and diamagnetic analyses revealed that the 2223 phase was significantly enhanced by high-valence cation (V5+, Nb5+, Ta5+, etc.) doping in BiSrCaCuO samples. The optimum nominal composition was Bi1.6M0.4Sr2Ca2Cu3 O(y)(M =

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Oxochromium (V) tetraphenylporphyrin complexes, O = Cr (V) TPP (Cl) PhI. O = Cr-(V) TPP (N3) PhI and O = Cr (V)TPP (p-CH3OC6H4O)1/2PhI were isolated from the reaction of Cr (III) TPP (Cl). Cr (III) TPP (N3) Py or Cr (III) TPP (p-CH3OC6H4O) THF with iodosy

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The electrical conductivities of pernigraniline after ion implantation with potassium ions were studied experimentally. Pernigraniline films were irradiated with doses ranging from 1 x 10(13) to 1 x 10(17) K+ ions/cm2 at 40 keV. The electrical conductivit

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氮气保护下二氯甲烷中铬(Ⅲ)四苯基卟琳衍生物在-40℃与亚碘酰苯反应,分离得氧配位铬(V)四苯基叶啉配合物:O=Cr(V)TPP(CI)PhI,O—Cr(V)TPP(N_3)PhI,O—Cr(V)TPP(p-CH_3O-C_6H_4O)1/2PhI.已经元素分析、可见、红外、顺磁、核磁和质谱法结构表征.这些配合物能氧化苯乙烯,环己醇,环己烯和环己烷,可作为细胞色素P—450模拟体系的活性中间体.

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With XRD, R- T curves, and a.c chi measurements, the doping and codoping effects of Sb and V to a Cu-deficient Pb-doped Bi system have been studied. A sample singly doped with V possesses a T(c) about 2 K lower than that of a sample singly doped with Sb. This is attributed to the different sites of their substitution. It was observed that for promoting 2223 phase formation, Sb and V works cooperatively, and the codoping of Sb may enhance the 2223 phase formed. With a low doping level of Sb, the optimum doping amount of V is 0.3, i.e., with a nominal composition of Bi1.5Pb0.3Sb0.06Sr2Ca2Cu2.4V0.3Oy. A sample in which the 2223 phase is the dominant phase and which has a zero resistance transition temperature of 105 K has been obtained.

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考察了不同组成的V-Sb-O系复合氧化物对丙烷氨氧化的催化活性.用XRD研究了催化剂的结构,利用程序升温方法研究了催化剂中氧的活动性和表面酸碱性,讨论了催化剂体相和表面结构与催化性能间的关系.结果表明,VSbO_4和Sb_2O_4间的协同作用是影响催化活性的重要因素.