Synthesis, crystal structure, and thermal property of a novel supramolecular assembly: (NH42810424)(CHNO) O-[H(V)O(]2H)4(10)28(2), constructed from decavanadate and caffeine

A novel 3D supramolecular assembly constructed from decavanadate and caffeine building blocks, (NH4)(2)(C8H10N4O2)(4)[H4V10O28].2H(2)O (1), has been synthesized in aqueous solution and characterized by elemental analysis, IR, H-1 NMR, V-51 NMR, TG-DTA, and single crystal X-Ray diffraction. The compound 1 crystallizes in monoclinic system, space group P2(1)/n, a = 15.801(1) Angstrom, b = 12.914(1) Angstrom, c = 15.913(2) Angstrom, beta = 113.55degrees, V = 2976.4 (5) Angstrom(3), Z = 2, R = 0.0498 with 6818 reflections. Water molecules, ammonium ions, and caffeine act as "cement" linking the polyanions into 1D chain along the c-axis by hydrogen bonding. In compound 1, extensive hydrogen-bond contacts and strong pi-pi interactions lead to an ordered 3D supramolecular framework. TG-DTA curves indicate that the weight loss of the complex can be divided into three stages.

LaNi2和LaNi2.28储氢电极性能研究

在真空电弧炉内制备了LaNi<,2>和LaNi<,2.28>合金,在超高压下处理LaNi<,2>合金,得到了具有Laves相结构的AB<,2>型金属间化合物,采用机械合金化装置对上述铸造合金进行了球磨处理,制备了LaNi<,2.28>非晶合金粉末.利用这些合金制备储氢电极,与烧结镍阳极组成单电池,研究各种电极的充放电性能,得到如下结论:(1)LaNi<,2>和LaNi<,2.28>铸态合金电极的放电容量分别为199.4mAh/g和241.0mAh/g;(2)铸态AB<,2>合金的循环性能和放电容量高于Laves相结构的AB<,2>型合金;(3)非晶化的合金电极非常容易被活化,但循环性能和放电容量都远低于铸态合金电极.

PT-28对常见无机酸和有机酸的萃取行为研究

系统地研究了2-乙基己氧基甲基膦酸二（2-乙基己基）酯（代号PT28）对硫酸、磷酸、硝酸、高氯酸、盐酸和醋酸六种酸的萃取行为,发现PT-28对硫酸、磷酸、高氯酸和盐酸均不萃取,只对硝酸和醋酸萃取,这与中性磷氧萃取剂甲基膦酸二甲庚酯（P350）和磷酸三正丁酯（TBP）对强酸的萃取有显著的不同,并对其萃取机理进行了讨论。

Preparation of borates doped with divalent rare earth ions (RE2+) in air and spectroscopy of divalent rare earth ions (RE2+ = Sm, Eu, Tm, Yb)

The spectroscopic feature of divalent Sm2+, Eu2+, Tm2+ and Yb2+ is discussed in this paper. Especially the spectroscopic properties of some berates containing tetrahedral BO4 group such as SrB4O7, SrB6O10 and BaB8O13 doped with these divalent ions are reported. When the divalent alkaline earth ion in these berates is replaced partially by the above trivalent rare earth ion, the charge carried in the produced defects can be used as reductant to reduce the doped rare earth ion into divalent state at high temperature even in air. Therefore, a convenient and safe method is provided to prepared phosphors doped with these divalent rare earths.

Ni_(69.5)Al_(28)Y_(2.5)粉末的机械合金化

对 Ni6 9.5Al2 8Y2 .5粉末进行球磨 ,获得 Ni Al金属间化合物 .研究粉末结构与球磨时间的关系 ,探索以中间合金的形式加入稀土元素的机械合金化方法 .结果表明 ,加入稀土元素后 ,用机械合金化的方法可以生成新的金属间化合物.

在空气下制备掺二价稀土的硼酸盐及二价稀土离子(RE~(2+)=Sm,Eu,Tm,Yb)的光谱特征

本文讨论了Sm2 + 、Eu2 + 、Tm2 + 、Yb2 + 等二价稀土离子的光谱特征 ,特别是在一些含四面体硼酸根的硼酸盐如SrB4 O7、SrB6 O10 和BaB8O13中它们的光谱性质。当以三价稀土离子取代化合物中的二价碱土离子时 ,利用不等价取代而产生的缺陷所带的电荷 ,可在高温的空气下使上述的稀土离子还原成二价 ,不需加入化学还原剂 ,从而提出了一个简便、安全的制备含二价稀土离子发光材料的方法

PT-28在硝酸体系中萃取三价镧系元素的研究

系统研究了２－乙基已氧基甲基膦酸工（２－乙基已基）酯（代号ＰＴ－２８）在硝酸介质中萃取三价镧系元素的行为，讨论了萃取剂浓度的变化、硝酸钠的浓度及温度变化对萃取率的影响，并对ＰＴ－２８． 萃取ＨＮＯ_３的机理进行了探讨。

Tb~(3+)在YAG中的发光及Tb~(3+)与Tm~(3 +)间的能量传递

采用溶胶 -凝胶方法合成了系列化合物 (Y1 -x- yTbxTmy) 3Al5O1 2 ,研究了Tb3+在该化合物中的发光及其浓度对发光性质的影响 ,以及Tb3+与Tm3+间的能量传递现象。

Calculation of chemical bond parameters in RBa2Cu4O8(R = Dy,Ho,Er,Tm,Yb) and Y2Ba4Cu7O14.3

Chemical bond parameters in RBa2Cu4O8(R = Dy, Ho, Er, Tm, Yb) and Y2Ba4Cu7O14.3 were calculated by using complex chemical bond theory. The results indicated that the bond covalency in CuO chain was larger than that in CuO2 plane. For metal atoms, the bond covalency of five coordinated case was larger than that of six coordinated case.

RBa_2Cu_4O_8(R=Dy,Ho,Er,Tm,Yb)和Y_2Ba_4Cu_7O_(14.3)的化学键参数计算

使用复杂晶体上化学键理论计算了 RBa2 Cu4 O8(R=Dy,Ho,Er,Tm ,Yb)和 Y2 Ba4 Cu7O14 .3 的化学键参数 .结果表明 ,Cu O链上的 Cu O键共价性大于它们在 Cu O2 面的共价性 .当金属元素与氧形成五配位时 ,其共价性的数值大于这些元素在六配位时的情形

The reduction of RE3+ in SrB6O10 prepared in air and the luminescence of SrB6O10 : RE2+ (RE=Eu, Sm, Tm)

The reduction of RE3+ to RE2+ (RE=Eu, Sm and Tm) in SrB6O10 prepared in air by high-temperature solid state reaction was observed. The luminescent properties of Eu2+ and Tm2+ show f-d transition and Sm2+ shows f-f transition at room temperature. Three crystallographic sites for Sm2+ in matrix are available. Vibronic transition of D-5(0)-F-7(0) of Sm2+ was studied. The coupled phonon energy about 108 cm(-1), was determined: from the vibronic transition. Due to the thermal population from D-5(0) level, (D1-FJ)-D-5-F-7 (J=0, 1, 2) transitions of Sm2+ were observed at room temperature. A charge compensation mechanism is proposed as a possible explanation.

Bond covalencies in R2BaCuO5 (R = Sm, Gd, Dy, Ho, Y, Er, Tm, Yb, Lu)

Bond covalencies in R2BaCuO5 (R = Sm, Gd, Dy, Ho, Y, Er, Tm, Yb, Lu) were calculated by means of a semiempirical method. This method is the generalization of the dielectric description theory of Phillips-Van Vechten-Levine-Tanaka scheme. The present paper presents the formula concerning the decomposing of complex crystals which are usually anisotropic systems into the sum of binary crystals which are isotropic systems. It can be seen that although the bond covalency is related to many physical quantities, it is mainly influenced by bond valence or bond charge, and a higher bond valence will produce higher bond covalency.

The bond ionicity in RBa2Cu3O7 (R=Pr, Sm, Eu, Gd, Dy, Y, Ho, Er, Tm)

RBa2Cu3O7 (R = Pr, Sm, Eu, Gd, Dy, Y, Ho, Er, Tm) has been studied using complex chemical bond theory. The results indicated that with the decreasing of R radius, the ionicities for all considered types of bond decrease. This is in good agreement with the experimental fact that T-c decreases with the decreasing of R radius. PrBa2Cu3O7 with no Ba-site Pr in this calculation is also predicted to be a superconductor. This supports the conclusion obtained by Blackstead et al. The ionicity for each bond obeys the following order: Ba-O > R-O > Cu(2)-O(1) > Cu(2)-O(2,3) > Cu(1)-O(4) similar to Cu(1)-O(1).

LiMgAlF_6 : Tm~(3+) 的合成与光谱特性

采用高温固相反应法，ＬｉＦ／ＭｇＦ２／ＡｌＦ３＝１２０／１１０／１００，烧结温度为１００８Ｋ，烧结时间为４ｈ，在流动的高纯Ａｒ中合成了ＬｉＭｇＡｌＦ６：Ｔｍ３＋。对其结构和发光特性进行了研究。

YP_5O_(14):Er~(3+),Tm~(3+)晶体的合成

研究了水热法合成晶体,浓度配比、生长温度对晶体生长习性的影响.合成了一系列化学计量比的Y_(1-x-0.3)Er_(0.3)Tm_xP_5O_(14)(x=0.01～0.1)晶体,观察和分析了晶体的缺陷及成因,测定和讨论了晶体结构.