2∶18磷钼杂多酸(盐)在H_2O_2分解反应中的催化作用

研究了2:18磷钼杂多酸(盐)(Dawson结构)对H_2O_2分解反应的催化行为。实验结果表明,H_6(P_2Mo_(18)O_(62))和1:12磷钼杂多酸H_3(PMo_(12)O_(40))相同,对H_2O_2分解无活性,而其盐类(Fe~(3+)、Cu~(2+))则有很好的催化活性,但对H_2O_2分解的动力学行为不同于1:12磷钼杂多酸盐,符合二级动力学反应关系式。这可能和这两种结构中抗衡阳离子所处环境不同有关。杂多酸阴离子中引入V,部份取代钼后所得实验结果与1:12磷钼钒杂多酸完全相同,表明引入的钒离子在两种结构中不仅有相同的环境而且是催化剂的活性种。     

Structural chemistry of the cation-ordered perovskites Sr2CaMo1−xTexO6 (0?x?1)

The crystal structures of Sr₂CaMoO₆ and Sr₂CaTeO₆ have been determined at room temperature by neutron powder diffraction. Both compounds crystallize in the perovskite structure with a rock-salt ordered array of Ca²⁺ and M⁶⁺ cations (M=Mo, Te) on the six-coordinate sites (space group P2₁/n (no. 14); for M=Mo, a=5.76228(7), b=5.84790(7), , β=90.194(1)°, for M=Te, a=5.79919(9), b=5.83756(8), , β=90.194(1)°). Compositions in the solid solution Sr₂CaMo_1−xTe_xO₆ have been synthesized and shown by X-ray diffraction to adopt the same ordered structure. The results are used in a discussion of the cation oxidation states in Ca₂FeMoO₆ and to establish the similarity between the structural chemistry of hexavalent Mo and Te.     

High Intensity Trip-Multiplet Transitions,a Reality! Synthesis,Properties, and Crystal Structure of l-Bis(triphenylphosphine)iminium trans-Dibromophthalocyaninato(2–)molybdate(III)

Oxophthalocyaninato(2–)molybdenum(IV), activated by bromine oxidation prior to use, reacts with fused triphenylphosphine in the presence of bis(triphenylphosphine)iminium bromide to yield linear-bis(triphenylphosphine)iminium trans-dibromophthalocyaninato(2–)molybdate(III), ^l(PNP)^trans[Mo(Br)₂pc^2?]. It crystallizes triclinic with crystal data: a = 10.506(1) Å, b = 12.436(2) Å, c = 12.918(2) Å, α = 76.186(1)°, β = 67.890(1)°, γ = 68.689(1)°; space group P1 (No. 2); Z = 1. Mo^III is in a pseudo-octahedral coordination geometry with the bromo ligands in trans-arrangement. The Mo? N_p and Mo? Br distance is 2.043(10) and 2.588(1) Å, respectively. The PNP cation adopts a linear conformation. In the IR spectrum v_as(Mo? Br) is observed at 218 cm^?1 and v_as(P? N) of the linear (P? N? P) core at 1406 cm^?1. Cyclic and differential-pulse voltammetry show two quasi-reversible cathodic processes at ?1.15 and ?0.53 V vs. Ag/AgCl. The first is assigned to a phthalocyaninate directed reduction (pc^2?/pc^3?), while the latter arises from a Mo directed reduction (Mo^III/Mo^II). Spectral monitoring confirms the reversible Mo^III/Mo^II reduction. Two quasi-reversible anodic processes at 0.60 and 1.27 V are assigned to the successive Mo directed oxidation with redox couples Mo^III/Mo^IV and Mo^IV/Mo^V. For the first time, three very intense spin-allowed trip-quartet transitions are observed in the electronic absorption spectra at 7140 (TQI), 16890 (TQ2) and 18700 cm^?1 (TQ3) together with a sing-quartet transition at 15850 cm^?1 and characteristic ?Q”? region with maximum at 28500 cm^?1 and ?N”? region at 37400 cm^?1. All electronic excitations are of comparable intensity. A prominent low temperature emission at 6690 cm^?1 is assigned to a spin-forbidden trip-sextet.     

钌（Ⅲ）－钼酸盐－罗丹明B离子缔合显色反应的研究及分析应用

钌（Ⅲ）钼酸盐－罗丹明Ｂ离子缔合显色体系分光光度测定钌，λｍａｘ为５７０ｕｍ，ε＝９．０５×１０５Ｌ·ｍｏｌ（－１）·ｃｍ（－１），相对标准偏差２．５％。线性范围０～１．２μｇ／２５ｍＬ。大量常见金属不干扰Ｒｕ的测定。方法用于某些岩矿和冶金产品中钉的测定，获得满意结果。     

用异丙肾上腺素检定钼酸根离子

将医用药物异丙肾上腺素引入分析化学作新显色剂 ,研究了异丙肾上腺素与 5 9种离子的反应 ,报道了异丙肾上腺素与Mo7O6 - 2 4 进行显色反应的最佳条件、灵敏度、选择性和界限比 ,建立了微量的Mo7O6 - 2 4 简便检定新方法 ,检出限量为 0 .0 39μg ,稀释限为 1∶6 .4× 10 6 。     

表面活性剂对Al2O3吸附MoO4^2—的影响

土壤自溶液中吸附MoO_4~(2-)会影响植物生长。前人对这一吸附过程已作过一些研究。本文报导阴离子表面活性剂十二烷基硫酸钠(SDS),阳离子表面活性剂氯化十六烷基吡啶(CPC)和非离子表面活性剂吐温-20(TW-20)对Al_2O_3吸附MoO_4~(2-)的影响。 实验所用吸附剂为层析用中性Al_2O_3(上海五四农场化学试剂厂),SDS(化学纯,广东石岐化工厂),CPC(化学纯。上海试剂一厂),TW—20(试剂级),其余试剂均为分析纯,含钼液用Na_2MoO_4配制。     

双锰卟啉应用于钼酸根电位传感器的研究

以[MnT(p-CH3)PP]2O为活性物质、以o-NPOE为增塑剂PVC膜制成的新型高效电位型传感器来测定MoO42-离子浓度。该电极具有线性能斯特斜率为30.5的响应特征,其工作浓度范围为2.1×10-6~1.0×10-1mol/L,pH范围为5.0~12.5,响应时间不超过15 s,对常见干扰离子有较高的选择性,并被应用于实际样品中MoO42-含量的测定。     

Molybdate and molybdate/permanganate conversion coatings on Mg-8.5Li alloy

A novel environment-friendly conversion coating for Mg-8.5Li alloy was obtained by immersing in a solution of molybdate. The concentration of ammonium molybdate and the addition of potassium permanganate were discussed in this experiment. The surface morphology of the conversion coatings was observed by scanning electron microscopy (SEM), and the chemical composition was investigated by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The corrosion resistance of Mg-8.5Li alloy and conversion coatings were investigated by means of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and weight loss measurement. The results showed that the coatings with cracked morphology were homogeneous and uniform. The conversion coatings were mainly composed of metal-oxide as detected by XPS. The results of electrochemical measurement and weight loss measurement revealed that the molybdate conversion coating had better corrosion resistance than bare alloy and chromate conversion coating, and the molybdate/permanganate conversion coating had lower corrosion current density and higher coating resistance than the molybdate conversion coating.     

聚乙烯醇存在下钼酸盐和罗丹明B光度法测定钪

在聚乙烯醇存在下，钪相杂多酸和罗丹明Ｂ（ＲＢ）形成离子缔合物，其最大吸收位于５７０ｎｍ，表观摩尔吸光系数ε值为５．６２×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１，服从比耳定律范围０－１．０μｇＳｃ／２５ｍＬ，检出限１．１ｎｇ／ｍＬ（ｎ＝９），考察了５０多种外来离子影响，缔合物的摩尔组成为Ｓｃ：Ｍｏ：ＲＢ＝１：１２：６，方法用于地质样品中钪的分析，结果满意。