IR AND ESR STUDIES OF THE REDUCED HETEROPOLYMOLYBDOVANADOPHOS PHORIC ACIDS H_(3+n)PMo_(12-n)V_nO_(40) (n=0,2,4)

The reducibility and isotope exchange ability of different oxygen bonds (O_b, O_p, O_t) in the Keggin structure of heteropolymolybdates (H_(3+n)PMo_(12-n)V_nO_(40)) containing zero, two or four vanadium atoms as well as the changes of structure of heteropolyacids during reduction were investigated by IR, ESR and ~(18)O isotope exchange. The results obtained showed that the order in the reducibility of different oxygen bonds is O_b>>O_p≈O_t, the replacement of Mo by V affects obviously the reducibility of various oxygen bonds: O_b increases while O_p and O_t decrease. ~(18)O exchange rate of O_b, O_p, O_t is not different, comparatively speaking, the isotope exchange of oxygen of the heteropolyacids containing vanadium atoms is more difficult than PMo_(12). The ESR spectra indicate that two kinds of Mo~(5+) ions with different coordinations are present in PMo_(12) (n=0) during reducing process, their g values are g_⊥~A=1.971, g_(?)~A=1.912 and g_⊥~B=1.965, g_(?)~B=1.861 belonging respectively to the d     

卡拉胶与槐豆胶协同相互作用及其凝胶化

讨论了卡拉胶与槐豆胶（ＬＢＧ）形成凝胶的共混比例、最佳膨化温度和膨化熟成时间，以及制备温度和体系盐离子浓度对凝胶化的影响．     

阻抗谱法确定扩散系数

给出了阻抗谱法确定扩散系数的理论和方法;以钒酸盐阴极材料Na_(1+x)V_3O_(?)(L.T.)为例,应用本方法计算给出了Li~+在阴极中的扩散系数为10~(?)-10~(-9)cm~2·s~(-1);最后还对误差来源进行了讨论. 关键词：     

聚异亚甲亚胺分子间氢键的形成及其对导电性能的影响

采用量子化学ＭＮＤＯ、ＣＮＤＯ／２－ＣＯ方法，探讨了聚异亚甲亚胺（ＨＣ＝Ｎ－Ｎ＝ＣＨ）ｘ分子链间Ｎ…Ｈ－Ｃ型氢键形成的可能性和氢键构成，分析了这种氢键影响高聚物导电性能的规律。     

碳涂覆光纤的最新进展

本文首先介绍了气密性光纤的发展过程，接着重点分析了碳涂覆光纤的两个重要参数：长期可靠性和抗氢渗透性。引入了新的衡量碳涂覆光纤抗氢渗参量－缺氢渗因子，最后介绍了西安应用光学研究所碳涂覆光纤“八．五”末的进展情况，以及国内外现状比较。     

ISOLATION AND PROPERTIES OF MOLYBDE-NUM SERIES OF HETEROPOLY BLUE WITH KEGGIN STRUCTURE

The present paper reports the methods for preparing and isolating 8 kinds of 1:12 molyb-denum series of heteropoly blue complexes K_yH_zXMo_(22)O_(40)·nH_2O (X=Si, P, As, Ge). Theproducts were characterized by elemental analyses, potential titration, polarograms, cyclicvoltammetry, IR spectra, visible--UV spectra, X--ray powder diffraction, XPS and ~(31)P NMR.The single crystal structure of 4-electron molybdenum--silicon heteropoly blue was measuredand the positions of reduced molybdenum atoms were determined, i.e. they were located atMo(3), Mo(7), Mo(8) and Mo(10). The experimental results show that the heteropoly blueremains Keggin structure. ESR spectra of heteropoly blue solids were first studied, fromwhich it was found that the delocalization extent of 2-electron heteropoly blue and 4--electronheteropoly blue is smaller than that of 1-electron heteropoly blue. The study of thermal prop-erties shows that the thermal stability increases with the increase of the reduction extentof heteropoly blue. Th     

烷烃物理化学性质的四参数方程

烷烃物理化学性质的四参数方程张向东，詹庆云，赵立群（辽宁大学化学系，沈阳１１００３６）（丽水师专，３２３０００）（沈阳化工学院，１１００２１）在物性与结构的定量关系（ＱＳＰＲ）的研究中，受到普遍关注的是拓扑指数法，这是由于拓扑指数由分子拓扑图得到不依...     

双2:17钼磷系列稀土杂多蓝的合成和性质研究

首次合成和离析了八种以缺位型Dawson结构钼磷杂多阴离子为配体的稀土杂多蓝K_(17)H_2[Ln-(P_2Mo_(17)O_(61))_2]·nH_2O和K_(17)H_4[Ln(P_2Mo_(17)O_(61))_2]·nH_2O(Ln=La,Pr,Sm,Yb).通过元素分析、电位滴定、红外光谱、紫外光谱、极谱、循环伏安、X射线光电子能谱、热重-差热分析和电子顺磁共振对杂多蓝进行了表征.实验结果表明,杂多阴离子还原为杂多蓝后,性质发生了某些变化,但结构基本不变,配体P_2Mo_(17)O_(61)~(10-)仍为a_2型.