K_2NiF_4型Dy_(0.5)Sr_(1.5)MO_4(M=Mn,Fe,Co,Ni)稀土复合氧化物的合成和催化性能考察

用重稀土镝的氧化物与锶、锰、铁、钴、镍的硝酸盐为原料,制备了A_2BO_4型Dy_(0.5)Sr_(1.5)MO_4(M=Mn,Fe,Co,Ni)稀土复合氧化物,用XRD技术考察了物相,合成了K_2NiF_4型四方结构的Dy_(0.5)Sr_(1.5)MO_4,并研究了其催化性能。对结构容纳因子的适用性作了讨论。     

K2NiF4型结构的A2－xSrxBO4(A＝La, Dy, B＝Mn, Fe, Co, Ni)希土复合氧化物的合成

以典型的轻希土镧和重希土镝及碱土金属锶作为Ａ位离子，以过渡金属锰、铁、钴、镍作为Ｂ位离子，合成了Ｋ２ＮｉＦ４型结构的Ａ２－ｘＳｒｘＢＯ４希土复合氧化物，采用粉末Ｘ射线衍射技术考察了反应条件等因素对生成Ｋ２ＮｉＦ４型四方（Ｔ）结构上析影响，实现结果表明，四方结构的形成不仅与几何因素有关，而且与各组分的物理化学性质有关。各个不同的组成，生成四方相的温度范围也有所不同。适当地提高反应温度以及延长灼烧时间     

K2NiF4型希土复合氧化物Eu2-xSrxNiO4+δ的合成、结构及还原性能

利用柠檬酸配合物分解法合成了单相的K₂NiF₄型希土复合氧化物Eu_2-xSr_xNiO_4+δ(0.5≤x≤1.2),粉末X射线衍射分析表明,在x为0.6～0.7的范围内,物相从空间群为Fmmm的正交相转变成空间群为I4/mmm的四方相,随着Sr²⁺的加入,部分Ni²⁺转变为Ni³⁺,其转变量与理论值接近。反映结构稳定性的高温还原峰温与晶胞参数c有对应关系,表明化合物的结构稳定性取决于AO层与ABO₃层的层间距离。     

K_2NiF_4型Eu_(2-x)Sr_xCuO_4稀土复合氧化物的合成、结构及还原特性

研究了具有K2 NiF4 型结构的Eu2 -xSrxCuO4 复合氧化物的合成、物相结构及其还原特性。发现用络合 凝胶法制备时 ,Eu2 -xSrxCuO4 复合氧化物的生成温度为 110 0℃左右 ,粉末XRD表明Eu2 -xSrxCuO4 复合氧化物属四方晶系 ,空间群为I4/mmm ,其晶胞参数随x的增加而增加。当x≥ 0 7时 ,多余的Sr不能进入晶胞而呈游离的SrO形式存在 ,同时在物相中也存在一定数量的CuO物相。Eu2 -xSrxCuO4 系列复合氧化物对CO和甲烷的催化氧化反应的活性在x较小时随着x的增加而增加。     

A_2BO_4型复合氧化物Dy_(0.5)Sr_(1.5)Mn_(1-x)Ni_xO_4(0≤x≤1)的Rietveld分析和CO氧化催化活性

X射线衍射Rietveld分析和微反分析表明,A位含Dy的A_2BO_4型过渡金属稀土复合氧化物Dy_(0.5)Sr_(1.5)Mn_(1-x)Ni_xO_4(0≤x≤1),是空间群为I4/mmm的四方相K_2NiF_4型结构,A位和B位约有3%至7%的占位无序缺位.健价计算表明,B位Mn的平均价态在3.73至3.77之间,Ni在2.84至2.96之间.对CO氧化催化活性顺序为X=0.2>0.4>0.6>0.8>1. 0.X=0.2的样品,在空速5000h~(-1),463K时,CO转化率达80%.     

Fe2Co0.5Ni0.5O4复合氧化物的制备及其电磁学性质

Fe2Co0.5Ni0.5O4复合氧化物的制备及其电磁学性质;纳米铁钴镍复合氧化物;固相反应;网状结构     

A_2BO_4型催化活性材料结构与性能的研究Ⅰ．［La_（k－x）Sr_x□_（1－k）］_2Cu_（1－y）□_yO_（4－δ）体系

以硝酸盐为原料，用柠檬酸络合法按［Ｌａ１－ｋＳｒｘ□ｋ－ｘ］２ＣｕＯ４（Ｘ＝０、０．０５、０．１、０．１５、０．２，ｋ＝０．０２５）的配比制备了５个样品．应用多晶Ｘ射线衍射法研究了此Ｌａ－Ｓｒ－Ｃｕ－Ｏ系列Ａ２ＢＯ４型复合氧化物的非完整结构．结构研究表明，此系列结构空位型非完整的存在，使结构中Ｂ位的铜离子变价为Ｃｕ２＋和Ｃｕ３＋．但是，随着Ａ位Ｓｒ加入量的增加，Ａ位空位的减少，结构中Ｂ位Ｃｕ３＋量随之减少，Ｃｕ２＋量随之增加，样品对于ＣＯ氧化的催化性能缓慢下降，而ＮＯ还原的催化能力增强．高价态的Ｃｕ３＋的存在是实现对ＣＯ催化氧化的条件；而Ｃｕ２＋给电子能力促进了Ｎｏ－的生成，是ＮＯ催化还原的活性来源．从此系列样品的催化性能和精细结构的研究可得出，适当地调节Ａ２ＢＯ４型结构中Ａ位和Ｂ位的空位及Ｓｒ２＋的掺入量，使Ｂ位Ｃｕ２＋和Ｃｕ３＋保持适当的比例，可获得ＣＯ催化氧化和ＮＯｘ催化还原同时具有较高活性的催化活性材料．     

K2NiF4型Co系稀土复合氧化物合成及氧化性能

K2NiF4型Co系稀土复合氧化物合成及氧化性能;氧化反应     

NdSr_（1－x）M_xNiO_4（M＝Ca，Ba）的合成，结构和电学磁学性

用固相法首次合成了ＮｄＳｒ＿（１－ｘ）Ｍ＿ｘＮｉＯ＿４（Ｍ＝Ｃａ：０．０≤１．０；Ｍ＝Ｂａ：０．０≤ｘ≤０．６）系列复合氧化物，并研究了其结构，红外光谱，电学性质和磁学性质。除ＮｄＣａＮｉＯ以正交晶系结晶外，其它试样的结构均属于四方晶系。ＩＲ谱显示随Ｃａ￣（２＋）离子含量的增加，ＮｄＳｒ＿（１－ｘ）Ｍ＿ｘＮｉＯ＿４的Ｎｉ－Ｏ键缩短，Ｃａ￣（２＋）和Ｂａ￣（２＋）引入ＮｄＳｒＮｉＯ＿４以取代Ｓｒ￣（２＋），使试样由金属性导电转变为半导体性导电；随Ｃａ￣（２＋）含量增加，试样的室温电阻率增大。７７～３００Ｋ磁化率与温度关系曲线显示，所有试样的Ｎｉ￣（３＋）都以低自旋状态存在。     

Synthesis,Crystal Structure and Reducibility of K2NiF4 Type Oxides Sm2—xSrxCuO4

K2NiF4 type compounds Sm2-xSrxCuO4(0≤x≤1.2)were prepared.Rietveld refinement of powder diffraction data shows that the crystal system of these compounds belongs to T′ type tetragonal structure of space group I4/mmm,and the addition of Sr causes a dramatic shift of the O(I) ions along the c axis from Sm(Sr) toward Cu while scarcely affecting the Cu-O(Ⅱ）bond in basal CuO4 phane.From XRD data,it can be seen that when 0.0≤x≤0.6,Sm2-xSrxCuO4 belongs to a singlephase K2NiF4 type structure,while at x≥0.7,both the free SrO phase and the CuO phase exist in these compounds.From the results of XPS and rietveld refinement,it can be seen that after replacing Sm^3 with Sr^2 of lower valence,the valence of Cu and Sm does not change apparently,and thus some defect must be formed at the oxygen ion positions and/or position A on A2BO4 to keep charge balance and to stabilize the structure.     

ELECTROREDUCTION MECHANISM OF Ni(DMG)-2 COMPLEX STUDIED WITH QUANTUM CHEMICAL METHOD

The electronic structures of the species Ni(DMG)_2, (Ni(DMG)_2)~- and (Ni(DMG)_2)_(2-) have been studied by INDO quantum chemical method. The results have clearly shown that in the first stage of the electroreduction of Ni(DMG)_2, one electron interacts with the d orbitals on the nickel atom, while in the further stage the second electron interacts with the p orbitals on the nitrogen atoms. It conforms with our electrochemical experimental studies which showed that not only Ni(Ⅱ) is reduced but also DMG is catalytically reduced during the reduction of Ni(DMG)_2.     

SYNTHESIS AND STRUCTURE OF A POLYMERIC 1,3-BENZENEDICARBOXYLATO COMPLEX OF Mn(II) WITH PHENANTHROLINE

Abstract

A novel Mn(II) complex bridged by 1,3-benzenedicarboxylate (BDC) has been synthesized by the diffusion method. The complex crystallizes in space group P2₁/c with a = 8.345(2), b = 10.427(1), c = 18.756(2) Å, β = 100.19(1)°. Each BDC bridges three Mn(II) atoms through two carboxyl groups with different coordination modes to form a complex polymeric chain. The coordination geometry around the Mn(II) atom is seriously distorted from the normal octahedron. Large deviations of the donor atoms out of the coordination planes and unexpected bond angles around Mn(II) and donor O atoms suggest the existence of an electrostatic interaction between Mn(II) and donor atoms in the complex. Close stacking of aromatic rings is observed in the complex, the distance between the neighboring phen planes being 3.2085 Å.     

The relationship between thermodynamic properties and local atomic structure of Al-TM (TM = Mn,Fe, Co,Ni, Cu) melts

The relationship between structure and thermodynamic properties of Al- transition metal (TM) (TM = Mn, Fe, Co, Ni, Cu) melts had been studied by using the results of X-ray diffraction experiments, reverse Monte Carlo simulations and the model of ideal associated solution (MIAS). It was considered that local atomic structure of melts is determined by dense non-crystalline atomic packing and energy of interatomic interactions. This allowed to choose the types of associates for the MIAS. It is shown that the prominent role of the atomic packing factor in the Al-Mn, Al-Fe melts leads to correlation between the local atomic ordering of melts and the one of relevant polytetrahedral phases and defines a set of associates. Strengthening of heteroatomic interactions in the Al-Co, Al-Ni melts leads to an increase of the energy factor role in determining their structure and properties that reduces the number of associates from three for the Al-Mn melts to one for the Al-Ni.     

铜(Ⅱ)与N(2-羟基乙基)水杨醛亚胺配合物的合成、结构和热分解

人们在探索新的有效抗癌药物时,发现了一些Schiff碱及其和某些金属生成的配合物具有抗癌作用。为研究此类配合物的抗癌作用和结构的关系,我们合成了一系列Schiff碱类配合物。 本文合成了Cu(Ⅱ)与N(2-羟基乙基)水杨醛亚胺配合物,培养出了单晶,通过X射线单晶衍射确定了配合物的晶体和分子结构,并对其热分解过程进行了初步探讨。     

X-ray and neutron powder diffraction study of the double perovskites Ba2LnSbO6 (Ln=La, Pr, Nd and Sm)

The crystal structures of Ba₂LnSbO₆ (Ln=La, Pr, Nd and Sm) at room temperature have been investigated by profile analysis of the Rietveld method using either combined X-ray and neutron powder diffraction data or X-ray powder diffraction data. It has been shown that the structure of Ba₂LnSbO₆ with Ln =La, Pr and Nd are neither monoclinic nor cubic as were previously reported. They are rhombohedral with the space group . The distortion from cubic symmetry is due to the rotation of the LnO₆/SbO₆ octahedra about the primitive cubic [111]_p-axis. On the other hand, the structure of Ba₂SmSbO₆ is found to be cubic. All compounds contain an ordered arrangement of LnO₆ and SbO₆ octahedra.     

Crystal structure of Ca2Ln3Sb3O14 (Ln=La, Pr, Nd and Y): A novel variant of weberite

The crystal structures of Ca₂Ln₃Sb₃O₁₄ (Ln=La, Pr, Nd and Y) and Ca₂Sb₂O₇ at room temperature were refined by the Rietveld method using combined X-ray and neutron powder diffraction data. Ca₂Sb₂O₇ adopts the weberite structure having the space group Imma. The structures of Ca₂Ln₃Sb₃O₁₄ are, however, neither the orthorhombic nor the tetragonal chiolite as has been suggested previously. They crystallize in the monoclinic space group I2/m11 belonging to a hitherto unknown type of deformation of the parent (orthorhombic) weberite structure.     

1,3-Bis(2-alkyltetrazol-5-yl)triazenes and their Fe(II), Co(II) and Ni(II) complexes: Synthesis,spectroscopy, and thermal properties. Crystal structure of Fe(II) and Co(II) 1,3-bis(2-methyltetrazol-5-yl)triazenide complexes

Complexes ML¹₂ and ML²₂, with M = Fe^II, Co^II, Ni^II, and 1,3-bis(2-R-tetrazol-5-yl)triazenide ligands L¹ (R = Me) and L² (R = ^tBu), have been synthesized by the reaction of corresponding 1,3-bis(2-R-tetrazol-5-yl)triazenes with metal(II) salts in basic media and characterized by IR, UV–Vis spectroscopy, thermal and X-ray diffraction analyses. Both 1,3-bis(2-R-tetrazol-5-yl)triazenes were found to deprotonate on coordination and act as tridentate chelating ligands forming distorted MN₆ octahedra around metal(II) cations.