CaO-SiO2-Al2O3-MgO-Na2O-CrOx炉渣中铬氧化物的非化学计量研究

采用化学平衡法研究了1673和1773 K下CaO-SiO2-Al2O3-MgO-Na2O-CrOx渣系中铬氧化物的非化学计量. 用化学分析法确定了平衡时渣中各价态铬氧化物的含量, 计算出了平衡时铬氧化物CrOx的非化学计量数x、活度比和炉渣的光学碱度值, 研究了温度、碱度、氧分压和铬氧化物总量对这些参数的影响. 结果表明, 铬氧化物的非化学计量数x随温度的升高、氧分压的降低和铬氧化物总含量的增加而减小, 随碱度的增大而增大; 温度、氧分压和铬氧化物总量对平衡时各渣样的理论光学碱度基本没有影响;铬氧化物的活度比随氧分压的升高而减小, 随温度的升高而增大. 推导得到的铬氧化物非化学计量的缺陷方程和实验结果均表明氧分压为影响其非化学计量性的主导因素.     

拓扑指数Y_M与二元氧化物的光学碱标

提出了一个新的拓扑指数YM,并用YM 研究了二元氧化物光学碱度的新标度。研究表明 ,YM 与二元氧化物的光学碱度呈良好的线性关系。计算了一百多个二元氧化物的光学碱度值 ,结果与二元氧化物的实际酸碱性顺序符合得很好。新方法可标度周期表中二元氧化物的光学碱度。     

光学碱度的理论分析及其在炉渣中的应用

以表征氧化物酸碱度的 L 函数与光学碱度 A 相关,得到了 Lewis 碱度和Lux-Flood 碱度间的良好相关关系,求得 Fe(Ⅱ)、Fe(Ⅲ)、Mn(Ⅱ)等过渡金属氧化物的 A 值.以扩展休克尔(Hückel)分子轨道计算法半定量地分析了光学碱度,得出了与 Duffy 定性模型一致的结论.运用光学碱度并结合 Masson 的硅酸盐离子聚合理论提出了计算多元系炉渣 No~(2-)的经验方法并由此统一地与钢铁冶炼中各种炉型炉渣的分配比相关,获得了较满意的结果.     

含钛玻璃光学碱度的测量

以Ｃu＾２＋为探针，成功地测得了含钛玻璃体系的光学碱度，并发现二氧化钛对体系组合 碱度的贡献与基质玻璃度有关，而且并非总是同一常数，这一结果将有助于进一步解决这类体系的碱度测量问题。     

氧化物系碱度的ESCA研究

氧化物系的酸碱性至今尚无一套完整的标度。Duffy等根据Pb~(2+)等离子(d~(10)s~2组态)在氧化物玻璃系中的Rydberg跃迁提出光学碱度的概念,但这种碱度测量只适用于对紫外光透明的少数体系。Imagawa则根据Cu~(2+)在碱金属硼酸盐等玻璃系中的ESR谱变化而提出另一种碱度。     

玻璃体系中折射碱度的测定

根据ｌｅｗｉｓ的观点,物质的酸碱性与其内部的电子密度分布有关。一些光学特征(如吸收、折射等)是由介质内部电子云分布所决定的,因而反映这些光学特征的光学参数与ｌｅｗｉｓ碱度之间存在着必然的联系,光学碱度[1]的概念就是由此提出的。摩尔折射Ｒ反映了分子中电子云(主要是价电子云)在外电场中变形能力的大小,它与折射率ｎ的关系可通过其分子量Ｍ和密度ｄ由ＬｏｒｅｎｔｚＬｏｒｅｎｔｚ公式得到:Ｒ=ｎ2-1ｎ2 2·Ｍｄ摩尔折射度与折射率一样具有加和性,因此在氧化物玻璃中可由玻璃的摩尔折射度减去阳离子折射度而得到氧离子的离子折射度…     

ZnGa2O4的制备及其光学性能

ZnGa2O4的制备及其光学性能;ZnGa2O4; 荧光; 固相法     

Al2O3涂敷TiO2纳米晶粒的制备及其抗絮凝性研究

纳米材料特异性能的开发与利用,是当今纳米材料科学研究中的热点之一.国外新近报道了[1～3]TiO2纳米晶粒在光学增益体系中的一种新应用.据报道,将TiO2纳米晶粒散布到染料罗丹明过氯酸盐的甲醇溶液中,在Nd:YAG 532 nm激光激发下,产生出奇特的光学现象:发射光纯度极高,波长宽度为2～3 nm,发射峰幅度成10倍地放大,激发能量有明确的阈值,且为各向同性发射.     

氧化物碱标与Sanderson电荷分数

目前的酸碱理论中，以Lewis酸碱理论最具概念上的广泛性和本质上的深刻性．但其应用还局限于定性，为使这一方法定量化，并解决固体体系酸碱性的表征问题，miffy提出了光学碱度概念D’．对一些氧化物的光学碱度值，在理论上可由Pauling电负性进行计算，实验中通过探针离子光谱跃迁测定．但DUffy的方法还仅限于对主族氧化物体系的应用．在Pauling电负性基础上发展起来的Sanderson电负性能更好地表示化合物中原子的特征，在标度氧化物特性方面应比Pauling电负性具有更精确的意义．本文从Sanderson电负性均衡原理“咄发，由Sanderson电荷分…     

In2O3电子结构与光学性质的第一性原理计算

采用基于密度泛函理论框架下的第一性原理平面波超软赝势方法, 计算了In2O3电子结构和光学线性响应函数, 系统研究了In2O3电子结构与光学性质的内在关系. 利用计算的能带结构和态密度分析了带间跃迁占主导地位的In2O3材料的能量损失函数、介电函数、反射图谱, 根据电荷密度差分图分析了In2O3材料的化学和电学特性. 研究结果表明In2O3光学透过率在可见光范围内高达85%, 可作为优异的透明导电薄膜材料. 同时, 计算结果为我们制备基于In2O3透明导电材料的设计与大规模应用提供了理论依据, 也为监测和控制这一类透明导电材料的生长过程提供了可能性.     

Sc2MgGa2 and Y2MgGa2

Scandium magnesium gallide, Sc₂MgGa₂, and yttrium magnesium gallide, Y₂MgGa₂, were synthesized from the corresponding elements by heating under an argon atmosphere in an induction furnace. These intermetallic compounds crystallize in the tetragonal Mo₂FeB₂‐type structure. All three crystallographically unique atoms occupy special positions and the site symmetries of (Sc/Y, Ga) and Mg are m2m and 4/m, respectively. The coordinations around Sc/Y, Mg and Ga are pentagonal (Sc/Y), tetragonal (Mg) and triangular (Ga) prisms, with four (Mg) or three (Ga) additional capping atoms leading to the coordination numbers [10], [8+4] and [6+3], respectively. The crystal structure of Sc₂MgGa₂ was determined from single‐crystal diffraction intensities and the isostructural Y₂MgGa₂ was identified from powder diffraction data.     

Zur Kenntnis der Dialkalimetalldichalkogenide β-Na2S2, K2S2, α-Rb2S2, β-Rb2S2, K2Se2, Rb2Se2, α-K2Te2, β-K2Te2 und Rb2Te2

On Dialkali Metal Dichalcogenides β-Na₂S₂, K₂S₂, α-Rb₂S₂, β-Rb₂S₂, K₂Se₂, Rb₂Se₂, α-K₂Te₂, β-K₂Te₂ and Rb₂Te₂ The first presentation of pure samples of α- and β-Rb₂S₂, α- and β-K₂Te₂, and Rb₂Te₂ is described. Using single crystals of K₂S₂ and K₂Se₂, received by ammonothermal synthesis, the structure of the Na₂O₂ type and by using single crystals of β-Na₂S₂ and β-K₂Te₂ the Li₂O₂ type structure will be refined. By combined investigations with temperature-dependent Guinier-, neutron diffraction-, thermal analysis, and Raman-spectroscopy the nature of the monotropic phase transition from the Na₂O₂ type to the Li₂O₂ type will be explained by means of the examples α-/β-Na₂S₂ and α-/β-K₂Te₂. A further case of dimorphic condition as well as the monotropic phase transition of α- and β-Rb₂S₂ is presented. The existing areas of the structure fields of the dialkali metal dichalcogenides are limited by the model of the polar covalence.     

Crystal Structures of [Bu2Sn(O2PPh2)2], [Ph2Sn(O2PPh2)2], and [PhClSn(O2PPh2)OMe]2. Raman Spectra of [Ph2Sn(O2PPh2)2] and [PhClSn(O2PPh2)OMe]2

[(n‐Bu)₂Sn(O₂PPh₂)₂] ( 1 ), and [Ph₂Sn(O₂PPh₂)₂] ( 2 ) have been synthesized by the reactions of R₂SnCl₂ (R=n‐Bu, Ph) with HO₂PPh₂ in Methanol. From the reaction of Ph₂SnCl₂ with diphenylphosphinic acid a third product [PhClSn(O₂PPh₂)OMe]₂ ( 3 ) could be isolated. X‐ray diffraction studies show 1 to crystallize in the monoclinic space group P2₁/c with a = 1303.7(1) pm, b = 2286.9(2) pm, c = 1063.1(1) pm, β = 94.383(6)°, and Z = 4. 2 crystallizes triclinic in the space group , the cell parameters being a = 1293.2(2) pm, b = 1478.5(4) pm, c = 1507.2(3) pm, α = 98.86(3)°, β = 109.63(2)°, γ = 114.88(2)°, and Z = 2. Both compounds form arrays of eight‐membered rings (SnOPO)₂ linked at the tin atoms to form chains of infinite length. The dimer 3 consists of a like ring, in which the tin atoms are bridged by methoxo groups. It crystallizes triclinic in space group with a = 946.4(1) pm, b = 963.7(1) pm, c = 1174.2(1) pm, α = 82.495(6)°, β = 66.451(6)°, γ = 74.922(6)°, and Z = 1 for the dimer. The Raman spectra of 2 and 3 are given and discussed.     

Electrochemical study of (NEt4)2Cl2FeS2MoS2 and (NEt4)2Cl2FeS2MoS2FeCl2

Summary The ability of [MoS₄]^2–, anions to be used as ligands for transition metal ions has been widely demonstrated, especially with Fe²⁺. The present study has been restricted to linear complexes such as (NEt₄)₂ [Cl₂FeS₂MoS₂] and (NEt₄)₂[Cl₂FeS₂MoS₂FeCl₂]. Their electrochemical properties are described: upon electrochemical reduction, these compounds yield MoS₂, as a black precipitate, and an iron complex in solution, assumed to be [SFeCl₂]^2–. The electrochemical reduction goes through two electron transfers, coupled with the breakdown of the molecular skeleton: a DISPl and an ECE mechanism. Depending on the solvent, the following equilibrium may be observed: [Cl₄Fe₂MoS₄]^2–[Cl₂FeMoS₄]^2–+FeCl₂. The equilibrium constant, K_D, was evaluated by differential pulse polarography. K_D is tightly related to the donor number of the solvent.     

The alkali hypophosphites KH2PO2, RbH2PO2 and CsH2PO2

The structures of the hypophosphites KH₂PO₂ (potassium hypophosphite), RbH₂PO₂ (rubidium hypophosphite) and CsH₂PO₂ (caesium hypophosphite) have been determined by single‐crystal X‐ray diffraction. The structures consist of layers of alkali cations and hypophosphite anions, with the latter bridging four cations within the same layer. The Rb and Cs hypophosphites are isomorphous.     

Syntheses,Spectroscopic Studies,and Crystal Structures of Me2Sn(O2PPh2)2, Ph2Pb(O2PMe2)2, and Ph2Pb(O2PPh2)2

Me₂Sn(O₂PPh₂)₂ ( 1 ), Ph₂Pb(O₂PMe₂)₂ ( 2 ), and Ph₂Pb(O₂PPh₂)₂ ( 3 ) have been synthesized by the reactions of Me₂SnCl₂ or Ph₃PbCl with the corresponding diorganophosphinic acid in methanol. X‐ray diffraction studies show that the diorganophosphinate groups behave as double bridges between the metal atoms leading to polymeric ring‐chain structures with M₂O₄P₂ (M = Pb, Sn) eight‐membered rings. The organic groups bonded to the metal atoms are in trans‐position in the resulting octahedral arrangement around the metal atoms. The IR and the mass spectra were reported and discussed.     

Thermal decomposition of Me3SnO2PCl2, Me2Sn(O2PCl2)2 and Ph3SnO2PCl2

TG and DTA studies on Me₃SnO₂PCl₂, Me₂Sn(O₂PCl₂)₂ and Ph₃SnO₂PCl₂ were carried out under dynamic argon atmosphere. The results show that the decomposition proceeds in different stages leading to the formation of Sn₃(PO₄)₂ as a stable product. This compound was characterized by IR spectroscopy. Decomposition schemes involving reductive elimination reactions were proposed.