锂离子筛的制备及其交换性能研究

用浓度为0.5mol/L的盐酸对高温固相合成的前体LiMn2O4进行酸洗脱锂,制得锂离子筛HMn2O4,并在不同pH值和温度下进行了Li 交换性能的研究,同时运用XRD和TEM进行了相应表征。结果表明,锂离子筛吸附交换前后晶体结构只发生了细微变化,但都仍为尖晶石型结构;交换反应在前10min速率最快,约20min就趋于平衡;Li 交换总量随pH值增大而升高,其中pH=7时交换容量为18.5526mg/g;Li 交换量和交换选择性随温度的升高而显著增强。     

Lithium insertion into In2S3 studied by perturbed γ-γ angular correlation

Li_xIn₂S₃ was electrochemically prepared with different small amounts x of lithium (0?x?0.13) in order to maintain the initial crystallographic structure of the thiospinel In₂S₃. About 10¹² radioactive ¹¹¹In ions have been implanted into these samples at 400 keV to perform PAC experiments in the temperature range from 10 to 773 K. The results are compared to previous experiments with undoped In₂S₃ samples. According to the structure of In₂S₃ in the β-phase, which belongs to the I4₁/amd space group having a unit cell with 32 In and 48 S atoms and the cell parameters α=7.61 Å and c=32.28 Å, three different electric field gradients were observed. Within two different temperature ranges dynamical EFGs occur, which are clearly influenced by the insertion of Lithium. The strong dependence of one EFG on the Li concentration x can be correlated to the effective charge of the In ions. This correlation is discussed with respect to XRD analyses of the Li_xIn₂S₃ samples and to XANES measurements on a similar sample.     

二溴羟基苯基荧光酮—乳化剂OP荧光熄灭法测定微量铬（Ⅵ）

本文基于Ｃｒ（Ⅵ）－二溴羟基苯基荧光酮（ＤＢＨ－ＰＦ）－ＯＰ体系的荧光熄灭效应，提出一种测定痕量铬（Ⅵ）的新荧光方法。在ｐＨ２．４－４．１的ＨＣｌ－ＮａＡｃ缓冲介质和ＯＰ存在下，Ｃｒ（Ⅵ）与ＤＢＨ－ＰＦ形成１：２的橙红色络合物，络合物的最大激发发工和发射波长分别是３６５ｍｍ和５２８ｎｍ。铬（Ⅵ）量在０．０５－１．５μｇ／２５ｍｌ范围内与△Ｆ呈线性关系，检测限是２．０ｎｇ／ｍｌ。方法用于电镀废液，废     

A Kinetic Aspect of the Thermal Dehydration of Dilithium Tetraborate Trihydrate

The reaction process of the thermal dehydration of dilithium tetraborate trihydrate, Li₂B₄O₇3H₂O, was reinvestigated from a viewpoint of reaction kinetics. On the basis of the results of thermogravimetry, constant rate thermal analysis, powder X-ray diffractometry, infrared spectroscopy and scanning electron microscopy, it was confirmed that the reaction proceeds via three consecutive kinetic steps characterized by different activation energies. The first and second kinetic steps, accompanied by the destruction of the original crystal structure of the reactant, seem to be assigned to the surface and internal reactions, respectively. During the third kinetic step, the thermal dehydration of hydrated amorphous intermediate, produced at the second kinetic step, and crystallization of the final dehydration product, Li₂B₄O₇, are likely to take place concurrently.This revised version was published online in November 2005 with corrections to the Cover Date.     

Das erste Titanat mit „Stuffed Pyrgoms”︁: RbNa3Li12[TiO4]4 = RbNa3Li8{Li[TiO4]}4

The First Titanate with ?Stuffed Pyrgoms”?: RbNa₃Li₁₂[TiO₄]₄ = RbNa₃Li₈{Li[TiO₄]}₄ By heating a well grounded mixture of the binary oxides Rb₂O, Na₂O, Li₂O, and TiO₂ [Rb:Na:Li:Ti = 1.1:3.1:12.5:4.0; 780°C, 41 d] we obtained RbNa₃Li₈{Li[TiO₄]}₄ as colourless platelike crystals. This first titanate with ?stuffed pyrgoms”? is isostructural with RbNa₃Li₈{Li[SiO₄]}₄, CsKNa₂Li₈{Li[SiO₄]}₄ and CsKNaLi₉{Li[SiO₄]}₄ [2]. The compound crystallizes tetragonal I4/m with a = 1 125.8(1) pm and c = 652.4(1) pm (Guinier-Simon-Data, Z = 2). The structure was determined by four-cyrcle-data (Siemens AED2, MoK) and leds to the residual values R = 3.7% and R_w = 3.1% (additional data see text). The Madelung Part of Lattice Energy (MAPLE), Effective Coordination Numbers (ECoN), Mean Fictive Ionic Raddii (MEFIR) and the Charge Distribution in Solids (CHARDI) are calculated and discussed.     

Heterometall-Komplexe mit E6-Liganden (E = P,As)

Heterometallic Complexes with E₆ Ligands (E = P, As) The reaction of [Cp*Co(μ-CO)]₂ 1 with the sandwich complexes [Cp*Fe(η⁵-E₅)] 2 a: E = P, 2 b: E = As in decalin at 190°C affords besides [CpCo₂E₄] 4: E = P, 7: E = As and [CpFe₂P₄] 5 the trinuclear complexes [(Cp*Fe)₂(Cp*Co)(μ-η²-P₂)(μ₃-η^1:2:1-P₂)₂] 3 as well as [(Cp*Fe)₂(Cp*Co)(μ₃-η^2:2:2-As₃)₂] 6 . With [Mo(CO)₅(thf)] 3 and 6 form in a build-up reaction the tetranuclear clusters [(Cp*Fe)₂(Cp*Co)E₆{Mo(CO)₃}] 10: E = P, 11: E = As. 3, 6 and 11 have been further characterized by an X-ray crystal structure determination.     

氯代甲苯双电荷离子的单分子解离反应研究

研究了在70 eV电子轰击电离条件下，氯代甲苯及氯化苄产生的双电荷离子[C_7H_7Cl]~(2＋)、[C_7H_6Cl]~(2＋·)和[C_7H_5Cl]~(2＋)为母体的两种类型单分子解离反应．主要讨论了亚稳双电荷离子的异构化反应、失H解高的“偶电子规则”以及单分子电荷分离过渡态的结构．     

1H,13C,and19F NMR study of products of the interaction of the η5-cyclopentadienyldicarbonyliron(ii) anion,CpFe(CO)2 −, with pentafluorobenzoyl chloride

Interaction of the ⁵-cyclopentadienyldicarbonyliron(II) anion with pentafluorobenzoyl chloride affords C₆F₅COFe(CO)₂Cp, CpFe(CO)₂C₆F₄COFe(CO)₂Cp, and CpFe(CO)₂C₆F₄C₆F₄Fe(CO)₂Cp. The reaction products are characterized by¹H,¹³C and¹⁹F NMR spectra.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 935–937, May, 1994.     

Specific heat on Sr<Subscript>2</Subscript>Nb<Subscript>2</Subscript>O<Subscript>7</Subscript> and Sr<Subscript>2</Subscript>Ta<Subscript>2</Subscript>O<Subscript>7</Subscript>

Summary Specific heats on the single crystals of Sr₂Nb₂O₇, Sr₂Ta₂O₇ and (Sr_1-xBa_x)₂Nb₂O₇ were measured in a wide temperature range of 2-600 K. Heat anomalies of a λ-type were observed at the incommensurate phase transition of T_INC (=495 K) on Sr₂Nb₂O₇ and at the super-lattice phase transition of T_SL (=443 K) on Sr₂Ta₂O₇; the transition enthalpies and the transition entropies were estimated. Furthermore, a small heat anomaly was observed at the low temperature ferroelectric phase transition of T_LOW (=95 K) on Sr₂Nb₂O₇. The transition temperature T_LOW decreases with increasing Ba content x and it vanishes for samples of x>2%.     

Oxidative cyclocondensation of cyclic thio-and selenoureas. 5. 2-Thioxothieno-and 2-thioxopyrido[2,3-<Emphasis Type="Italic">d</Emphasis>]pyrimidin-4-ones

A study was carried out on the oxidative cyclocondensation of 2-thioxothieno-and 2-thioxopyrido[2,3-d]pyrimidin-4-ones. The thiophene ring with excess π-electron density facilitates the reaction, while the pyridine ring with diminished π-electron density hinders it. 2-Thioxothieno-[2,3-d]pyridimin-4-ones were converted into previously unreported 7H,13H-[1,2,4]thiadiazolo-[3,2-b:5,4-b′]bis(thieno[2,3-d]pyridimine-7,13-diones). __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1424–1427, September, 2007.