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1.
为满足现代通信技术的小型化、集成化与高可靠性的迫切要求,探索具有高介电常数、低介电损耗与低温度系数的微波介电材料引起了材料科学、化学、物理、电子等领域科学工作者的广泛关注,并已开发出复合钙钛矿结构Ba(Zn_(1/3)Ta_(2/3))O_3、钨青铜结  相似文献   

2.
WANG Peng  LIN Hua 《结构化学》2013,(12):1873-1879
A new quaternary rare-earth sulfide, Cs0.75(6)Er443(5)In3.32(6)S12 (1), is discovered by high temperature solid state reactions with a slight excess of CsCI flux. The structure is characterized by single-crystal X-ray diffraction data, while crystallizes in hexagonal space group P63/m (No. 176) with a = 12.0329(6), c = 3.8693(5)A, V= 485.18(7) A3, Z = 1, Mr = 1606.57, Dc = 5.499 g/cm3,μ = 25.457 mm-1, F(000) = 752, the final R = 0.0337 and wR = 0.0904 for 328 observed reflections with I 〉 2σ(I). Its structure features a three-dimensional framework with hexagonal channels that are centered by Cs cations. Such channels are formed by double chains of edge-sharing M(1)S6 (M(1) = Er(1)/In(1)) octahedra and single chains of Er(2)S6 triprism interconnected by corner-sharing. The syntheses, single-crystal analyses, optical band gap and magnetic property are reported.  相似文献   

3.
单相Ce0.5Zr0.5O2立方固溶体的高压高温合成   总被引:1,自引:0,他引:1  
以化学沉淀法制备的 Ce O2 和 Zr O2 纳米微粒为前驱体 ,首次在高压高温 (3 .1 GPa,1 0 73 K)下合成了单相 Ce0 .5Zr0 .5O2 面心立方固溶体 .使用 X射线衍射、TG-DTA、XPS、Raman、电子自旋共振谱和交流阻抗谱等对样品的结构、Ce离子的价态和导电性进行了表征 .实验结果表明 ,纳米 Ce O2 -50 % Zr O2 混合物在高压 (0 .9GPa以上 )高温 (1 0 73 K以上 )条件下可以发生固态反应 ,高压下固溶温度明显降低 .Ce0 .5Zr0 .5O2 面心立方固溶体在 773 K以下是热稳定的 ,不发生结构转变 ,固溶体中 Ce离子完全以 Ce4 + 形式存在 ,773 K退火也不引起 Ce4 + 向 Ce3 + 转变 ,晶格中氧缺位非常少 .Ce0 .5Zr0 .5O2 面心立方固溶体是离子导电 ,82 3 K时电导率 σ=1 .2× 1 0 -5S/cm,与纯 Ce O2 在同温度下的电导率同数量级 ;1 1 2 3 K时 σ=2 .1× 1 0 -3 S/cm,小于掺入稀土或碱土氧化物的氧化锆和氧化铈基电解质的电导率 .在高温区和低温区 ln(σT)与 1 /T的关系满足斜率不同的二条直线 ,低温活化能小于高温活化能 .固溶体的显微硬度 (50 g载荷 )为 572 HV.  相似文献   

4.
类钙钛矿结构新钽酸盐KSr2Ta3O10的合成、结构与层间特性   总被引:2,自引:0,他引:2  
类钙钛矿结构氧化物是由钙钛矿结构基元与其它类型结构基元组合而成的一种超结构复合氧化物.  相似文献   

5.
A new niobate compound with the chemical composition of Ba5LiTiNb9O30 was synthesized by doping Li^ into the system BaO-TiO2-Nb2O5 in conventional solid state reaction method. The crystalline structure was determined by X-ray diffraction analysis (XRD). The results showed that crystal structure of Ba5LiTiNb9O30 belongs to tetragonal tungsten bronze structure with space group P4bm and its unit cell parameters: a=b=1.2512(2) nm, c=0.4008(5)nm. The microstructure of reaction products was observed by scanning electron microscopy (SEM).  相似文献   

6.
类钙钛矿新铌酸盐Ba5LaTi2Nb3O18的合成、结构与介电特性   总被引:2,自引:0,他引:2  
为满足现代通信技术小型化、集成化与高可靠性的迫切要求,探索具有高介电常数、低介电损耗与低温度系数的微波介电材料引起了材料科学、化学、物理和电子科学等领域科学工作者的广泛关注,并已开发出复合钙钛矿结构的Ba(Mg1/3Ta2/3)O3、Ba(Zn1/3Ta2/3)O3和钨青铜结构的Ba6-3xLn8+2x·Ti18O54及Ba2Ti9O20等实用化的高性能材料[1~7].这类材料均由氧八面体共顶连接,而且氧八面体内(B位)、外(A位)阳离子比例等于或略大于1,由此,我们推测在B位与A位阳离子比例略小于1的类钙钛矿结构中也极有可能存在具有优良介电性能的新材料,因此对通式为AnBn-1O3n(n=5,6,7,8)的系列新化合物进行了系统的合成、结构与介电性能研究[8,9].本文报道在BaO-La2O3-TiO2-Nb2O5体系中合成的具有5层类钙钛矿结构的新铌酸盐Ba5LaTi2Nb3O18,发现该材料具有较好的介电性能.  相似文献   

7.
1 INTRODUCTION The design and assembly of organic-inorganic solid-state materials with active physical properties, such as materials with electrical, magnetic and opti- cal properties, has become a focus of a great deal of interest in recent years[1, 2].…  相似文献   

8.
A novel organic fluorophor with high solid state luminescent efficiency based on 1,4-bis(2,2-di(pyridin-2-yl)- vinyl)benzene (BDP2VB) was designed and synthesized. It emits faintly in solution, but becomes a strong emitter in the aggregate state, demonstrating its aggregation induced emission (AIE) property. According to the crystal struc- ture analysis, J-type aggregation was formed in the packing mode of the molecule, which was demonstrated to be beneficial to gain high fluorescent quantum efficiency in solid state. Additionally, the emission color of BDP2VB can change dramatically in solid state as well as in solution by the protonation stimuli.  相似文献   

9.
The crystal structure of a sodium titanium oxide Na2TiO3 obtained by high temperature solid state reaction method was determined from single-crystal X-ray diffraction study. The compound crystallizes in the monoclinic system, space group C2/c, Mr = 141.88, a = 9.885(1), b = 6.4133(8), c = 5.5048(7) , β = 115.50(3)o, V = 314.99(7) 3, Z = 4, Dc = 2.992 g/cm3, λ = 0.71073 , μ = 27.80 cm–1, F(000) = 272, T = 295 K, R = 0.0189 and wR = 0.0512 for 30 variables and 370 contributing unique reflections. The three-dimensional structure in Na2TiO3 is constructed by the TiO(1)4O(2) and NaO(1)3O(2)2 groups. The titanium atoms are grouped in the form of trigonal bipyramid and arranged along the c axis by sharing the edges. The structure is compared with other structures of related A2BO3 compounds.  相似文献   

10.
The single crystal of [Ba(H2O)2(C6H12O6)2Cl2] was obtained based on the phase equilibrium results. Its structure was determined by X-ray crystallographic analysis. The crystals are monoclinic and in space group C2/c with a=1.901 7(2) nm, b = 0.682 13(8) nm, c = 0.162 60(2) nm,β=96.593(2)°and V= 2.095 3(4) nm3, Z= 4, DC=1.917 g·cm-3. In its solid state, this supramolecular complex is a three-dimensional network with double layers connected by hydrogen bondings. The molecule structure of [Ba(H2O)2(C6H12O6)2Cl2] has a central barium ion that is coordinated to two water molecules, two chlorides, and four hydroxyls from the two inosi-tols. Losing the coordinating water is controlled by random nucleation and growth mechanism (n = 2/3) and 3-dimensional diffusion mechanism (n=2).  相似文献   

11.
新化合物PbCuP2O7的单晶通过高温固相反应制备得到,使用X一射线四园衍射仪测定了它的单晶结构.PbCuP2O7属单斜晶系,空间群为P21/n,晶胞参数:α=5.381(1),b=8.2O5(2),C=12.57O(3)A,β=90.49(3)°,Z=4.使用1311个I>2σ(I)反射修正101个变量参数,最终收敛到R=0.O54.其晶体结构是由共顶点的CuO5四方锥和P2O7集团沿α轴形成较大的孔道所组成,Pb原子位于由两个四方锥和三个PO4四面体的棱所夹的五角形孔道中.  相似文献   

12.
New mixed-valent, Ni1+/Ni2+, metastable nickelate, La3Ni2O6, was synthesized by low-temperature reduction of La3Ni2O7 with CaH2. The crystal structure of La3Ni2O6 (space group: I4/mmm, a = 3.9686(1) A and c = 19.3154(6) A) was determined from powder neutron diffraction data by Rietveld analysis. The structure can be described as an intergrowth of LaO2 fluorite and double infinite layer (LaNiO2)2 blocks and represents the n = 2 homologue of the T'-type series Lan+1NinO2n+2. Such double T'-type structural arrangement has never been observed before. The 3d9/3d8 electronic configuration of Ni1+/Ni2+ and the presence of NiO2 infinite layers resemble electronic and structural features of the superconducting cuprates. X-ray absorption spectroscopy supports the 1+/2+ oxidation state and planar coordination of Ni in agreement with the structure determination.  相似文献   

13.
A novel polyoxometalate-based organic-inorganic polymer [{Ca(DMF)5}2SiMo12O40]n has been synthesized and characterized by elemental analysis, IR, UV and X-ray single-crystal structural analysis. The title compound crystallizes in a monocline lattice, P21/n, with a =1.3379(3), b = 1.9796(4), c = 1.4574(3) nm, β = 92.24(3)°, V = 3.8568(13) nm3, Z = 2, R1 = 0.083 and Rw = 0.2065. The result of crystal structure analysis indicates that Ca2+ is surrounded by seven coordination oxygen atoms with pentagonal bipyramidal geometry and bridged with terminal oxygen atom of polyanion in the structure. The compound contains an unprecedented one-dimensional linear chain built by alternate polyanions and cationic units through Mo-Od-Ca-O-Ca links in crystal. The IR spectra and X-ray crystallography analysis exhibit that there is a strong interaction between the polyanion and organic group in solid state. The electronic spectra (λ = 200-500 nm) for the title compound dissolved in the mixed solvent of acetonitrile and  相似文献   

14.
张登  吕赟  许新  丁少华  许岩 《无机化学学报》2012,28(6):1298-1304
本文分别采用水热和溶剂热的方法,以乙二胺和哌嗪为有机模板剂分别合成了两种新的三维孔道结构的稀土硫酸盐[Gd2(SO4)5(H2O)2][C2N2H10]2(1),[Eu2(SO4)5(H2O)2][C4N2H12]2(2),并且通过单晶X射线衍射、元素分析、红外、热重对两种化合物进行了表征。化合物1和2都属于单斜晶系,P21/c空间群。化合物1:a=0.652 1(4)nm,b=1.692 0(9)nm,c=2.023 3(11)nm,β=95.168(7)°,Z=4。化合物2:a=1.972 1(2)nm,b=1.927 1(2)nm,c=1.323 20(14)nm,β=92.307 0(10)°,Z=8。单晶结构分析表明,这两种化合物的无机骨架都是由SO4连接具有交替十六元环与八元环二维层形成的三维孔道结构。化合物2的固体荧光分析表明,在396 nm的激发波长下表现出Eu3+的特有发光性质。  相似文献   

15.
N,N-Dimethylaminoxygermane, H3GeONMe2, was prepared by the reaction of H3GeBr with LiONMe2 in dimethyl ether at -96 degrees C. The identity of H3GeONMe2 was proven by gas-phase IR and solution NMR spectroscopy (1H, 13C, 15N, 17O). It is an unstable volatile liquid compound. It decomposes by cleavage of a Ge-O and a Ge-H bond giving HONMe2 and an insoluble germanium hydride polymer (GeH2)n. This decomposition reaction has been modeled at the MP2/6-311G(d,p) level of theory by the homodesmotic reaction H3GeONMe2 + Ge2H6-->Ge3H8 + HONMe2, which is predicted slightly exothermic by 14 kJ mol-1. The molecular structure of H3GeONMe2 was determined by gas-phase electron diffraction supported by an ab initio geometry [MP2/6-311G(d,p)] and a force field [MP2/6-31G(d)]. The structure of the compound in the crystal lattice was determined by low-temperature crystallography using a single crystal of H3GeONMe2 grown in situ [C2H9NOGe, orthorhombic, Pnma, Z = 4, a = 8.1280(12) A, b = 9.7037(15) A, c = 7.0722(12) A]. Important bond lengths and angles (gas phase/solid state, A/deg) are Ge-O 1.785(2)/1.815(1), O-N 1.462(7)/1.460(2), N-C 1.460(4)/1.453(2), Ge-O-N 105.2(5)/104.6(1), O-N-C 105.8(5)/105.8(1), C-N-C 110.8(9)/111.2(2), Ge...N 2.587(6)/2.601(1). In the solid state the compound forms infinite chains by intermolecular Ge...O contacts of 2.808 A. The question of the attraction between Ge and N atoms is discussed with respect to reference Ge/O and N/O compounds, which have wider angles at oxygen than H3GeONMe2. For comparison the structures of the compounds H3CONMe2, H3SiONMe2, and H3SnONMe2 were also calculated to reflect the influence of the group 14 atom on the structure and to discuss the occurrence of weak E...N interactions in the compounds H3EONMe2.  相似文献   

16.
A series of Sc3+-doped spinel lithium manganese oxides Li1+xScyMn2-yO4(y=0.01, 0.02, 0.06, and 0.10)were synthesized by solid state reaction using LiOH·H2O, MnO2, and Sc2O3 as starting materials. The results of powder X-ray diffraction indicated that the doped Li1+xScyMn2-yO4 maintain the cubic structure of spinel phase Fd3m. The electrochemical properties were characterized by electrochemical methods. The initial discharge capacity reached 135 mAh/g and the capacity fading rate was less than 2% after 40 cycles. The spinel phase was well preserved after 40 cycles. The doping of Sc3+ effectively improved the cycleability of spinels, and was a promising way for the improvement of spinel LiMn2O4 cathode materials.  相似文献   

17.
在K2O-Fe2O3-Ta2O5三元系统中,新发现存在钽酸盐K6FeTa15O42,使用X射线衍射(XRD)、电子探针微区分析(EPMA)、扫描电镜(SEM)、差热分析(DTA)等方法对该化合物的晶体结构、成分、形态、光学性质、溶解性、熔点及密度进行了研究。新化合物K6FeTsa14O42晶体属于六方晶系,空间群P63/mcm,晶胞参数a=0.91221(1)nm,c=1.21084(4)nm,Z=1,V=0.87258nm^3。  相似文献   

18.
类钙钛矿新铌酸盐Ba3La2Ti2Nb2O15的合成、结构与介电特性   总被引:2,自引:0,他引:2  
为满足现代通信技术的小型化、集成化与高可靠性的迫切要求,探索具有高介电常数、低介电损耗与低温度系数的微波介电材料引起了材料科学、化学、物理和电子学等领域科学工作者的广泛关注,并已开发出复合钙钛矿结构[Ba(Zn1/3Ta2/3)O3]和钨青铜结构[Ba6-3xLn8+2xTi18O54]等实用化的高性.  相似文献   

19.
在K2O -Fe2O3-Ta2O5 三元系统中 ,新发现存在钽酸盐K6FeTa15O42,使用X射线衍射(XRD)、电子探针微区分析(EPMA)、扫描电镜(SEM)、差热分析(DTA)等方法对该化合物的晶体结构、成分、形态、光学性质、溶解性、熔点及密度进行了研究。新化合物K6FeTa15O42 晶体属于六方晶系,空间群P63/mcm,晶胞参数a=0.91221(1)nm,c=1.21084(4)nm,Z=1,V=0.87258nm3。  相似文献   

20.
A new bismuth oxalate Na(C5NH6)[Bi(H2O)(C2O4)2]2.4H2O has been obtained under hydrothermal conditions and characterized by X-ray diffraction.It crystallizes in mono-clinic, space group C2/m with a = 12.020(5), b = 11.190(8), c = 11.067(10)(A), β= 121.78(2)°,NaBi2CI3NH18O22, Mr= 981.24, V = 1265.4(16)(A)3, Z = 2, Dc = 2.575 g/cm3, μ(MoKα) = 14.005 mm-1, F(000) = 912, R = 0.0179 and wR = 0.0394.In the structure, the Bi(Ⅲ) centers are interconnected by oxalate ligands to produce honeycomb-like layers, which are further pillared by bridging ligand oxalate molecules to form a 3-D open-framework structure.Furthermore, the title compound exhibits blue luminescence with the emission peaks located at 394nm in the solid state at room temperature, and thus it could be useful in the field of photoactive materials.  相似文献   

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