Synthesis and Characterization of Tetraphenylphosphonium Halochromates

Ion-associated halochromates (halo=F, Cl, Br) from tetraphenylphosphonium cation (Ph₄P⁺) are synthesized by stepwise solvent extraction technique and characterized based on XRD, spectral and thermal studies. The Ph₄P⁺CrO₃Br^- crystal is tetragonal with a=b=12.368 and c=7.511 ∮A. Thermal stabilities of these complexes are found to be decreasing in the order of Ph₄P⁺CrO₃F^-> Ph₄P⁺CrO₃Cl^-> Ph₄P⁺CrO₃Br^-. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthesis and Characterisation of Tetraphenylarsonium Halochromates

Tetraphenylarsonium halochromate (halo=fluoro, chloro and bromo) complexes are synthesised and characterised by spectral and thermal studies. The effect of ionic size and electronegativity of halide ions on the infrared spectra, X-ray emission spectra, activation energy of the first decomposition step and thermal stability of the complexes are investigated. The complexes possess tetragonal unit cell with a=b=12.93 Å and c=7.68 Å.These complexes decompose in two exothermic stages. Cleavage of one Ph-As bond to give triphenylarsine and reduction of Cr(VI) to Cr(III) occur simultaneously. First step mass loss corresponds to the loss of two phenyl halide molecules and 3/2 moles of oxygen. The overall kinetics of the first step is described by diffusion controlled reaction mechanism with a function g(α)=[1?(1?α)^1/2]. The second step decomposition is due to the further degradation of triphenylarsine. The final product is Cr₂O₃.     

Solvothermal synthesis and characterisation of new one-dimensional indium and gallium sulphides: [C10N4H26]0.5[InS2] and [C10N4H26]0.5[GaS2]

Two new main group metal sulphides, [C₁₀N₄H₂₆]_0.5[InS₂] (1) and [C₁₀N₄H₂₆]_0.5[GaS₂] (2) have been prepared solvothermally in the presence of 1,4-bis(3-aminopropyl)piperazine and their crystal structures determined by single-crystal X-ray diffraction. Both compounds are isostructural and crystallise in the monoclinic space group P2₁/n (Z=4), with a=6.5628(5), b=11.2008(9), c=12.6611(9) Å and β=94.410(4)° (wR=0.035) for compound (1) and a=6.1094(5), b=11.2469(9), c=12.7064(10) Å and β=94.313(4)° (wR=0.021) for compound (2). The structure of [C₁₀N₄H₂₆]_0.5[MS₂] (M=In,Ga) consists of one-dimensional [MS₂]⁻ chains which run parallel to the crystallographic a axis and are separated by diprotonated amine molecules. These materials represent the first example of solvothermally prepared one-dimensional gallium and indium sulphides.     

Thermal behaviour and microstructural characterization of lanthanide sulphides

Thermal decomposition processes of rare earth sesquisulfides Ln₂S₃ (Ln= Lu, Y and Er) in O₂ flow up to 1590 K, have been studied. Decomposition takes place through incomplete oxidations and overlapping decomposition reactions. Two intermediate phases such as Ln₂O₂S and Ln₂O₂SO₄ are formed before the final more stable phase Ln₂O₃ (C-type) is obtained. Microstructural studies show the poor crystallinity of the intermediate products.We wish to thank the Centro de Microscopia Electrónica, U.C.M.) for facilities. This research was supported by the CYCIT project MAT 89-0768.     

聚苯硫醚/石墨复合物的微观结构

<正> 聚苯硫醚自一百年前第一次被合成以来虽已被广泛地研究,但对其结构的研究还是近年来的事。Tabor等人用X-射线衍射测定了聚苯硫醚的结构,确定其为正交结构,点阵参数为α=0.867nm,b=0.561nm,c=1.026nm。 由于高科技部门对具有导电性的高聚物的需求,人们在橡胶、高聚物中掺入导电材料粉末(如金属,石墨等),以得到具有不同电导率的高聚物材料,其电导率随导电粉末加入量的增加而加大,然后达到饱和。聚苯硫醚中加入石墨后,可获得电导率在10~(-4)—2s/m     

Long-range magnetic ordering in Ba2CoS3: A neutron diffraction study

Neutron powder diffraction has been used to determine the magnetic structure of the quasi-one-dimensional compound Ba₂CoS₃, which contains linear [001] chains of vertex-sharing CoS₄ tetrahedra, spaced apart by Ba²⁺ cations. At 1.5 K the Co²⁺ cations in the chains are antiferromagnetically ordered with an ordered magnetic moment of 1.97(4) μ_B per cation aligned along [100]. Each Co²⁺ cation is ferromagnetically aligned with four cation in neighbouring chains and antiferromagnetically aligned with two others.     

The ORD,CD and UV spectra of sulphides derived from carvone

The ord and cd spectra of aromatic and aliphatic sulphides derived from carvone are compared with the spectra of dicarvone sulphide and related compounds. The spectra are discussed in relation to the structure of the molecules, as evidenced by the nmr spectrum, and correlated with the electronic transitions involved.

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ORD-, CD- und UV-Spektren von Sulfiden des Carvons

Zusammenfassung Die CD- und ORD-Spektren aromatischer und aliphatischer Sulfide von Carvon werden mit Spektren von Dicarvonsulfid und verwandten Verbindungen verglichen. Die Spektren werden in bezug auf Molekülstrukturen, die durch NMR-Spektren bewiesen wurden, diskutiert und mit den betreffenden Elektronenübergängen in Wechselbeziehung gebracht.

     

三价砷阴离子AsS43-的化合物[InAsS4(2，2’-bipy)]2的合成及性质

用水热法合成了含三价砷阴离子AsS3-4的化合物[InAsS4(2,2′-bipy)]2。 该化合物晶体为单斜晶系,空间群为P21/c,晶胞参数a=0.89799(9) nm,b=2.1794(2) nm,c=1.43736(14) nm,β=91.274(2)°,V=2.8123(5) nm3。 在此化合物中用金属螯合物[In(2,2′-bipy)]3+稳定了不常见的三价砷阴离子AsS3-4,讨论了金属价态对最终产物结构的影响,并且研究了该化合物的半导体性质(禁带带宽1.35 eV)。     

优化迭代目标转换因子分析法在多组分混合物红外光谱解析中的应用

优化迭代目标转换因子分析法在多组分混合物红外光谱解析中的应用何锡文,陈鼎,王永泰（南开大学化学系、中心实验室,天津,３００００７１）关键词因子分析,相关性,红外光谱因子分析是一种多元统计方法,用其解析多组分混合物的红外光谱已有报道［１,２］。迭代目标...