Thermogravimetric analysis of the copper silicate mineral dioptase Cu6[Si6O18]·6H2O

There have been a few studies on the thermal decomposition of dioptase Cu₆[Si₆O₁₈]·6H₂O. The results of these analyses are somewhat conflicting and the conclusions vary among these thermo-analytical studies. The objective of this research is to report the thermal analysis of dioptase from different origins and to show the mechanism of decomposition. Thermal decomposition occurs over a very wide temperature range from around 400 to 730 °C with the loss of water. Two additional mass loss steps are observed at around 793 and 835 °C with loss of oxygen. The infrared spectra of dioptase in the hydroxyl stretching region enables the hydrogen bond distances of water molecules in the dioptase structure to be calculated. The large variation in the hydrogen bond distances offers an explanation as to why the decomposition of dioptase with loss of water occurs over such a wide temperature range.     

[6O]富勒烯的化学修饰

对近年来一些新的[60]富勒烯的化学修饰方法进行了综述。参考文献76篇。     

An analysis of the vibrational frequencies and amplitudes of the H5O+2 ion in H4SiW12O40·6H2O (TSA·6H2O) and H3PW12O40·6H2O (TPA·6H2O)

The infrared, Raman and inelastic neutron scattering (INS) spectra of TSA·6H₂O and TPA·6H₂O are in agreement with those expected for the presence of H₅O⁺₂ ions. Force fields for different assignment schemes are compared with the observed vibrational frequencies and the INS spectral profile. All but two schemes are eliminated. Whilst low-resolution INS spectroscopy cannot distinguish between these two schemes, the orientations of the vibrational ellipsoids for one scheme are in better agreement with those reported from low-temperature crystallographic studies of the H₅O⁺₂ ion.     

C~6~0O异构体的研究

本文用臭氧氧化C~6~0的苯溶液,用HPLC分析产物,室温下氧化产物只得到一个C~6~0O异构体组分峰。低温下产物得到两个C~6~0O异构体组分峰。多出的一个峰经实验与理论的研究,表明它很可能是异构体C~6~0O(C~s)。     

(enH2)5[(VO)12O6B18O36(OH)6]·2(H3O)·6H2O的水热合成和晶体结构

以NH4VO3,H3BO3,乙二胺,MoO3,H2O为原料,按物质的量比2∶20∶9∶3∶222,在180℃条件下晶化,得到黑色棱形晶体(enH2)5[(VO)12O6B18O36(OH)6].2(H3O).6H2O.单晶结构分析结果表明该化合物属三斜晶系,Pī空间群,晶胞参数a=1.336 8(3)nm,b=1.599 8(3)nm,c=1.663 4(3)nm,α=94.040(1)°,β=91.530(1)°,γ=95.830(1)°,V=3.528 1(12)nm3,Z=2,Dc=2.099 g/cm3,μ=1.649 mm-1,F(000)=2 228,15 641个可观察独立衍射点射点(I>2σ(I)),最后结构精修到偏离因子R1=0.047 5,wR2=0.150 4,S=1.039.该化合物的结构主要由阴离子簇[(VO)12O6B18O36(OH)6]12-构成.该阴离子簇由B18O36(OH)6十八元环夹在两个以共边交替相连形成的V6O18簇中间,通过共用氧原子形成三明治式结构新颖的硼-钒-氧离子簇,簇间填充了一些(enH2)2+离子和水分子.     

Syntheses and Crystal Structures of (H3O)(C3H5N2)[Mn(OH)6 Mo6O18]·3.5H2O and (H3O)3[Co(OH)6Mo6O18]·7H2O

The crystals of the title compounds (H3O)(C3H5N2)[Mn(OH)6Mo6O18]·3.5H2O 1 and (H3O)3[Co(OH)6Mo6O18]·7H2O 2 have been prepared and structurally determined by X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic, space group C2/c with a = 21.5018(9), b = 10.9331(5), c = 11.8667(5)A,β = 95.3570(10)o, V = 2777.5(2)A3, Z = 4, Dc = 2.802 g/cm3, Mr = 1171.80,μ(MoKα) = 3.173 mm-1, F(000) = 223, the final R = 0.0458 and wR = 0.1041 for 2093 observed reflections (I>2σ(I)); Compound 2 crystallizes in monoclinic, space group P21/c with a = 11.4042(12), b = 10.9481(11), c = 11.6722(12)A, β= 99.948(2)o, V = 1435.4(3)A3, Z = 2, Dc = 2.794 g/cm3, Mr = 1207.80,μ(MoKα) = 3.223 mm-1, F(000) = 1160, the final R = 0.0544 and wR = 0.1066 for 1906 observed reflections (I > 2σ(I)). Both compounds 1 and 2 adopt the Anderson structure, in which the anion is of centrosymmetry and formed by six octahedral edge-sharing MoO6 units surrounding the central MO6 (M = Mn or Co) octahedron.     

1D Chain-Like Architecture in Anderson Heteropolymolybdate {[Eu(H2O)6]2(TeMo6O24)}·6H2O: Synthesis and Characterization

A new Anderson-based heteropolymolybdate {[Eu(H₂O)₆]₂(TeMo₆O₂₄)}·6H₂O (1) has been hydrothermally synthesized and characterized by elemental analyses, IR, thermal stability analysis, XRD and single crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P-1, a = 9.4023(6) Å, b = 10.2530(7) Å, c = 10.6525(10) Å, α = 101.583(7)º, β = 108.024(7)º, γ = 107.150(6)º, V = 883.60(12) ų, Z = 1, R₁ = 0.0338, wR₂ = 0.0849. Compound 1 exhibits 1D chain-like structure formed by the alternative connection between Anderson type polyoxoanions [TeMo₆O₂₄]^6? and Eu³⁺ along a-axis. Compound 1 displays good fluorescent emission of the Eu³⁺ ion at room temperature.     

Synthesis of calcium titanate from [Ca(H2O)3]2[Ti2(O2)2O(NC6H6O6)2]·2H2O as a cheap single-source precursor

Calcium titanate (CaTiO₃) was conveniently synthesized by thermal decomposition of a single-source precursor [Ca(H₂O)₃]₂[Ti₂(O₂)₂O(NC₆H₆O₆)₂]·2H₂O at low temperature. This single-source precursor was characterized by elemental analysis, IR spectrum, thermal gravimetric analysis and X-ray single crystal diffraction. The calcined products at different temperature were further characterized by powder X-ray diffractions and IR spectra. The morphology, microstructure, and crystallinity of the resulting CaTiO₃ materials have been characterized by SEM and TEM. The BET measurement revealed that the CaTiO₃ powders had a surface area of 14.0 m²/g. In addition, the microwave dielectric properties of the resulting CaTiO₃ material have been measured.     

Preparation of Single Crystalline V6O13 Nanobelts

Ultralong beltlike nanostructures was successfully synthesized for V6O13 crystal by a hydrothermal route. The products are characterized by means of X-ray powder diffraction, transmission electron microscopy and high-resolution transmission electron microscopy. The experimental results give the evidence that the V6O13 nanobelts are pure, structurally uniform and single crystalline, with typical widths of 50 to 300 nm and lengths of up to a few millimeters.     

十钒酸盐K6V10O28.9H2O的合成与结构

本文报道了十钒酸盐Ｋ６Ｖ１０Ｏ２８．９Ｈ２Ｏ的合成及单晶结构分析结果。     

Synthesis of Molybdovanadates Coordinated by Oxalato Ligands. The Crystal Structure of K6[Mo6V2O24(C2O4)2]·6H2O

The oxalato complex of a polyoxomolybdovanadate, K₆[Mo₆V₂O₂₄(C₂O₄)₂]·6H₂O has been obtained by reaction of potassium molybdate, ammonium vanadate and tartaric or ascorbic acid. Such conversion of dicarboxylate into oxalate ions indicates the catalytic role of molybdenum. Complexes of analogous composition also were obtained in the reactions of MoO₃, V₂O₅ and potassium oxalate, or M ₂CO₃ (M = Rb, Cs) and oxalic acid. The centrosymmetrical molybdovanadate anion [Mo₆V₂O₂₄(C₂O₄)₂]^6- consists of six MoO₆ and two VO₆ edge-sharing octahedra to give the n -[Mo₆O₂₆]^4- structure. All complexes were characterized by powder and single crystal X-ray analyses, ESR and IR spectra and TG and DSC measurements.     

苯分子与Si6O18H12和Al6O24H30团簇模型相互作用的理论研究

粘土矿已经被广泛用来去除有机物,修复和净化被石油碳氢化合物污染的土壤和地下水. 我们选择高岭石作为研究对象,构造了Si₆O₁₈H₁₂和Al₆O₂₄H₃₀两个团簇模型分别代表高岭石的硅氧层表面和铝氧层表面,在MP2/6-31G(d,p)//B3LYP/6-31G(d,p)的理论水平上系统地研究了气态下苯分子和高岭石团簇模型的相互作用. 并进一步分析了苯分子和高岭石表面相互作用的各种气态性质,比如：优化的几何构型、结构参数、吸附能、自然键轨道电荷分布、振动频率变化、静电势、电子密度性质(次级氢键的电子密度和拉普拉斯算符值)和电子密度差分等. 优化的几何构型表明苯分子吸附在高岭石表面的本质可能是次级氢键的形成. 其他性质的结果进一步验证了次级氢键的存在,并指出苯更倾向于吸附在高岭石的铝氧层表面,且苯环和铝氧层表面形成近似90°的夹角.     

SrB6O10:Tb的热释光性质研究

通过高温固相法合成了SrB6O10：Tb热释光磷光体, 并系统地研究了Ce3＋, Li＋共掺杂, Tb3＋掺杂浓度以及60Co γ射线辐照剂量对其热释发光的影响, 同时观察了其热释光发射. 研究发现： Ce3＋, Li＋共掺杂对SrB6O10：Tb磷光体的热释光灵敏度并没有提高. Tb^3＋掺杂浓度对SrB6O10热释光磷光体的灵敏度有一定影响： 在从1%～10%（摩尔分数）的Tb3＋掺杂浓度范围内, 2%为最佳掺杂浓度. 在此掺杂浓度条件下, 用Chen的峰形法评估了此磷光体的动力学参数, 发现其遵守二级动力学;增加辐照剂量, 热释光发射也随之增强, 并在所研究的剂量范围内呈线性变化;在其三维热释光发射谱中, 观察到了Tb^3＋离子的特征发射.     

BaCl2-C6H12O6-H2O/(H2O+CH3CH2OH)体系在30 ℃时的相平衡研究

用等温溶解度法研究了BaCl2-C6H12O6-H2O/(H2O+CH3CH2OH)体系在30 ℃时的相平衡, 发现在体系中有一未见文献报道的不一致溶解的化合物BaCl2*2C6H12O6*2H2O生成. 研究结果为肌醇生产除杂质工艺提供了理论依据.     

Effects of CuCl2��6H2O and ZnCl2��6H2O on the viscosity of aqueous ethanol mixtures

The effects of CuCl₂ and ZnCl₂ on the viscosity in aqueous ethanol mixtures (10%–50% v/v) were studied in the concentration range 1.0×10⁻²–8.0×10⁻² mol·dm⁻³ at different temperatures. It was found that the viscosities increased with an increase in the concentration of the salts and percent composition of ethanol content, whereas it decreased with an increase in temperature. Ion-ion and ion-solvent interactions are determined with the help of A- and B-coefficients of Jones-Dole equation. The values of A- and B-coefficients are irregular and increase with a rise in temperature and also with an increase in ethanol contents for both salts. Negative values of B-coefficients show that ion solvent interactions is comparatively small and suggest that CuCl₂ and ZnCl₂ behave as structure breakers in aqueous ethanol mixtures. Thermodynamic parameters like the energy of activation (E _η ) and change in entropy of activation (ΔS*) were also evaluated which confirm the structure breaker behavior of salts in aqueous ethanol mixtures.