TG of a cotton fabric impregnated by sodium borate decahydrate (Na2B4O7·10H2O) as a flame-retardant

The effect of sodium borate decahydrate as a nondurable treatment on the flammability of 100% cotton fabric (woven plain 150 g m⁻²) has been investigated in this paper. The laundered bone-dried massed samples were impregnated with suitable concentrations of sodium borate decahydrate. Each bunches of fabrics were dipped into individual aqueous solutions of the salt, followed by means of squeeze rolls and drying at 110°C. By using a ‘vertical flame spread test’ the optimum add-on values to impart flame-retardancy onto cotton fabric was determined to be as 4.24 g salt per 100 g fabric. The objective of this study is thermogravimetry (TG) investigation of pure cotton, treated one with the salt at its optimum efficiency. So that outcomes could be compared and commented, finally the results obtained are in favor of ‘Chemical action theory’, ‘Condensed phase retardation’, ‘Dust or wall effect theory’ and also ‘Gas dilution theory’.     

High-pressure synthesis and characterization of the alkaline earth borate β-BaB4O7

The new orthorhombic barium borate β-BaB₄O₇ was synthesized under high-pressure/high-temperature conditions in a Walker-type multianvil apparatus at 7.5 GPa and 1100 °C, starting from stoichiometric mixtures of the binary oxides. β-BaB₄O₇ crystallizes in space group Pmnb with Z = 2 and lattice parameters a = 1099.4(2), b = 901.7(2), c = 430.73(9) pm, R1 = 0.0199, and wR2 = 0.0406 (all data). The network-structure is built up exclusively from BO₄-tetrahedra, linked via common corners. Its structural differences to the ambient-pressure phase α-BaB₄O₇ and structural agreements with the isotypic high-pressure phases β-MB₄O₇ (M = Ca, Hg, Sn) and the ambient-pressure phases MB₄O₇ (M = Sr, Pb, Eu) are discussed. β-BaB₄O₇ and a hypothetical BaB₄O₇ in the β-MB₄O₇ (M = Ca, Hg, Sn) structure were studied as high-pressure phases of α-BaB₄O₇, using density functional calculations. The transition pressure of α-BaB₄O₇ into the structure of β-BaB₄O₇ was calculated to 1.5 GPa; the transition pressure of β-BaB₄O₇ into BaB₄O₇ in the β-MB₄O₇ (M = Ca, Hg, Sn) structure to 7.5 GPa.     

Parameters of Li2O2 · H2O crystallization from the LiOH-H2O2-H2O ternary system

The decomposition kinetics of peroxide products contained in the liquid phase of the LiOH-H₂O₂-H₂O ternary system were studied, and the applicability of the solubility method to studying this system was demonstrated for hydrogen peroxide concentrations in the liquid phase from 2 to 6 wt % and temperatures of 21–33°C. The stabilizing influence of solid Li₂O₂ · H₂O on hydrogen peroxide decomposition was demonstrated. The temperature and concentration boundaries of existence were determined for the Li₂O₂ · H₂O phase, whose identity was verified by chemical analysis and qualitative X-ray powder diffraction analysis.     

Die Molarverhältnisse CO2∶O2 und N2O∶O2

Ohne Zusammenfassung     

Ga2O3-La2O3-Yb2O3-Er2O3(HO2O3)体系光谱性质的研究

根据稀土离子能级的特点,对Ga2O3-La2O3-Yb2O3-Er2O3(HO2O3)体系的光谱性质进行了探讨,发现它们有二类发光性质:Stokes发光和反Stokes发光,研究了发光强度和发射波长与掺杂离子的依赖关系,观察到由能量的共振转移引起的荧光浓度猝灭现象,并取得了最大发光强度时的掺杂离子浓度和一些规律性结果.     

P2O2-V2O5-TiO2的表面结构

P_2O_5-V_2O_5-TiO_2(简写为P-V-Ti)对芳烃氧化有良好的催化效果.丁烷氧化催化剂P-V体系的体相和表面结构已有一些报道.但P_2O_5对V-Ti的影响文献较少报道.本文用XRD,IR,TPD和ESR考察了P-V-Ti体系. 1.试剂和催化剂:草酸、偏钒酸铵、二氧化钛均为化学纯.将V_2O_5:TiO_2=11:89(重量)样品分别按 P/V原子比为0.1,0.3,0.6,1.0,1.5和2.5制成编号为P-0.1,P-0.3,P-O.6,P-1.0,P-1.5和P-2.5的催化剂.     

电子转移反应O2+O2·-→O2·-+O2的从头算研究

利用abinitio方法,在UHF,UMP2及不同基组3-21G,6-31G^*,6-311+G^*和UMP2(full)/6-311+G^*水平上,研究了O~2/O~2^.^-自交换电子转移反应。优化了电子转移前后反应物和产物的结构,研究了体系能量的变化,计算了自交换电子转移反应的内重组能。对UHF方法和UMP2方法的计算结果进行了比较,并与实验结果进行了对照。结果表明UHF方法由于没有考虑组态相互作用,计算结果存在较大偏差,UMP2(full)/6-311+G^*水平上的计算结果与实验值吻合较好。在UMP2(full)/6-311+G^*水平上计算了气相自交换电子转移反应速率常数。在优化了电子转移复合物结构的基础上考虑了溶剂效应的影响,计算了水溶液中的溶剂重组能。研究结果表明O~2/O~2^.^-体系电子转移反应的活化能主要来源于溶剂重组能的贡献。最后计算了该反应在水溶液中的反应速率常数。理论计算结果与实验值吻合得很好。     

Li2O﹒2B2O3-H2O过饱和溶液20℃结晶动力学研究

盐水溶液中存在过饱和现象，硼酸盐溶液的过饱和即是一例．其中，镁础酸盐体系过饱和溶液在不同浓度和温度条件下的液固相关系曾有多次报道［‘－’］；给出过许多有益的结果，也探讨了镁硼酸盐的结晶反应机理并拟合出相应的结晶动力学方程．这些工作对认识盐水溶液过饱和现象有重要意义．为了更广泛地认识和了解不同棚酸盐水溶液中的过饱和现象，本文采用动力学方法，首先对Li20·2B203－HZO过饱和溶液结晶过程进行了研究．1实验初始反应溶液中Li。O／BZO。（摩尔比）为1／2，按此配比计算并称取需要量的Li0H·H。O（A．R．）、H。…     

CLUSTER CONVERSION OF [MoW2O2(O2CEt)9]− TO [MoW2O4(O2 CEt)8]4- BY CHROMIUM HEXACARBONYL CRYSTAL STRUCTURES OF Na[MoW2O2(O2CMe)9] · H2O, [MoW2O2(O2CEt)6(H2O)3] ZnCl4 · 2H2O AND Na2Cr2[MoW2O4(O2CEt)8]2

Abstract

Reactions of Mo(CO)₆ with Na₂WO₄ · 2H₂O in refluxing carboxylic anhydride produce the triangular bioxo-capped mixed-metal carboxylate clusters Na[MoW₂O₂(O₂CR)₉] (R = Me, 1; Et, 2), the propionate being hydrolyzed in 2M HCl containing ZnCl₂ to form [MoW₂O₂(O₂CEt)⁶(H₂O)₃]ZnCl₄·2H₂O (3). Cluster 2 is converted to the incomplete cuboidal tetraanion [MoW₂O₄(O₂CEt)₈]^4- upon reacting with Cr(CO)₆ in propionic anhydride at 120°, the latter species being trapped by Cr^3± and Na^± ions in the reaction mixture to afford the octanuclear heterometallic chain-like cluster Na₂Cr₂ [MoW₂O₄(O₂CEt)₈]₂ (4). Clusters 1, 3 and 4 have been characterized by X-ray crystallography with the following crystal data, for 1: monoclinic, space group P2₁/c, a = 16.666(8), b = 11.096(3), c = 16.541(7) Å, β = 94.60(4)°, V = 3048.9 ų, Z = 4, R, Rw = 0.070, 0.079; for 3, monoclinic, space group Cm, a = 10.259(3), b = 15.756(3), c = 10.870(3) Å, β = 96.18(3)°, V = 1746.8 ų, Z = 2, R, Rw = 0.028, 0.034; for 4, triclinic, space group P-1, a = 13.013(5), b = 14.005(4), c = 12.357(4) Å, α = 109.71(2), β = 117.77(3), γ = 90.41(3)°, V = 1838.9 ų, Z = 1, R, Rw = 0.037, 0.042.     

MgO-B2O3-28%MgCl2-H2O体系O℃热力学非平衡态相图

采用结晶动力学方法对MgO-B2O3-28%MgCl2-H2O体系0℃时过饱和溶液的结晶过程进行了研究,结晶析出固相通过化学分析确定了组成,并用X-射线粉末衍射和红外光谱等对其进行了表征.给出了该体系0℃时的热力学非平衡态相图.该相图有4个相区,分别与H3BO3、MgO@3B2O3@7.5H2O、2MgO@2B2O3@MgCl2@14H2O和3Mg(OH)2@MgCl2@8H2O相对应.     

α?→?γ Lithium borate phase transition produced during the CO2 chemisorption process

CO₂ capture and storage are the most important issues to be tackled in the near future. For the last few years, different lithium ceramics have been proposed as possible CO₂ captors. In this article, the CO₂ chemisorption process on ??-LiBO₂, which had not been previously investigated, was studied. ??-LiBO₂ was synthesized and characterized by XRD, SEM and N₂ adsorption. Its CO₂ reactivity was evaluated by dynamic and isothermal thermogravimetric experiments. Results show that ??-LiBO₂ is able to react with CO₂. Additionally, there is a phase transformation from ??-LiBO₂ to ??-LiBO₂ during the CO₂ absorption. Although the CO₂ absorption was not considerably high, the results showed that lithium ceramics, containing boron, absorbed CO₂.     

209Bi NQR in Mixed Oxides 2Bi2O3· B2O3, 3Bi2O3· 5B2O3, and Bi2O3· 3B2O3

It was earlier found from nuclear quadrupole resonance (NQR) measurements and computer modeling that -Bi₂O₃, Bi₃O₄Br and mixed oxides Bi₂O₃· 2Al₂O₃, Bi₂O₃· 2Ga₂O₃, Bi₂O₃· 3GeO₂, and 2Bi₂O₃· 3GeO₂exhibit local ordered magnetic fields from 30 to 200 G. It thus follows that these compounds are not diamagnets in a conventional sence of the word. With the aim of revealing previously unknown magnetic properties in bismuth(III) oxide-based Main Group element compounds, the mixed bismuth–boron oxides 2Bi₂O₃· B₂O₃, 3Bi₂O₃· 5B₂O₃, and Bi₂O₃· 3B₂O₃were prepared and studied using ²⁰⁹Bi NQR. The quadrupole interactions of the ²⁰⁹Bi nuclei and their electronic environment were studied, the crystallochemical features of the compounds were discussed, and the conformity of the ²⁰⁹Bi results to the X-ray structure data was verified. The preliminary tests in the field of a permanent magnet showed that the resonance intensities increase in external magnetic fields, indicating that a magnetism of unknown nature develops in the titled compounds. It was found reasonable to continue studies of the magnetic properties of these compounds using single-crystal ²⁰⁹Bi NQR in external magnetic fields.     

Untersuchungen in den Systemen GeO2−Na2O, −K2O und −Rb2O

Zusammenfassung Die Systeme GeO₂–Na₂O, –K₂O und –Rb₂O werden röntgenographisch und differentialthermoanalytisch untersucht. Die früher beschriebene Verbindung Na₂Ge₄O₉ (I) erweist sich als identisch mit dem vonJ. F. White und Mitarbeitern angegebenen Na₄Ge₉O₂₀. Von der dargestellten isotypen Kalium-Verbindung werden die Gitterkonstanten ermittelt. Im analogen Rubidium-System läßt sich ein isotypes Enneagermanat bisher nicht nachweisen. Einkristallaufnahmen von Natriumtetragermanat [Na₂Ge₄O₉ (II)] ergeben eine hexagonale Elementarzelle mit 6 Formeleinheiten Na₂Ge₄O₉. Ebenso werden von den isotypen Kalium-und Rubidiumtetragermanaten die Gitterparameter bestimmt. Im Natrium-System stellt offensichtlich das Enneagermanat die stabile Phase dar, während das Tetragermanat nur durch rasches Abkühlen aus der Schmelze erhalten wird. Bei den Kaliumgermanaten ist dagegen das Tetragermanat die stabile Phase.Mit 2 Abbildungen     

ZrO2–Sc2O3 Solid Electrolytes Doped with Yb2O3 or Y2O3

Russian Journal of Electrochemistry - The effects of the Y2O3 and Yb2O3 co-doping impurities on the transport characteristics and stabilization of the cubic phase in solid solutions based on...     

气相中H2O2与N2O反应机理的探讨

采用RHF/AM1方法研究了H2O2与N2O的反应机理.计算结果表明,该反应是多步反应,先后通过2个过渡态（TS1,TS3）,1个内旋转位垒（TS2）,2个中间体（IM1,IM2）.其中从反应物Re到TS1为整个反应的决速步骤,速控步骤的活化能为323.04 kJ•mol－1.整个反应为一放热反应,放出的热量为147.67kJ•mol－1.