超声波辅助固液反应球磨制备ZnFe2O4纳米晶的研究

以α-Fe2O3和ZnO粉体为原料,在超声波辅助高能球磨作用下通过诱发固液相反应,并在低温下烧结合成了ZnFe2O4纳米晶粉末.采用X射线、透射电镜(TEM)对前驱体和烧结产物进行了表征,分析了球磨过程对粉体晶粒尺寸的影响和znFe2O4的形成过程.实验结果表明:超声波辅助固液球磨能在低温下烧结合成ZnFe2O4纳米晶,纳米晶的晶粒尺寸为15～25 nm;相比无超声波辅助下的固液球磨,超声波球磨降低znFe2O4烧结温度约50℃;同一烧结温度下,球磨时间越长,ZnFe2O4转化率越高,晶粒尺寸越小.     

ZnFe2O4纳米棒的制备和性能研究

以硫酸锌、氯化亚铁和草酸铵为原料,采用水热法和热分解法成功制备了ZnFe2O4纳米棒,并利用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、X射线能量色散分析谱仪(XEDS)、高分辨透射电子显微镜(HRTEM)、选区电子衍射(SAED)和振动样品磁强计(VSM)等测试手段对样品的化学成分、形貌、晶体结构和磁性能进行了表征.结果表明,制备的ZnFe2O4为结晶良好的单相尖晶石型结构,没有杂峰出现.样品形貌为一维纳米棒状结构,分散性良好.ZnFe2O4纳米棒直径约为200nm,长度约为1～2 μm,纳米棒由晶粒尺寸在15 ～ 20 nm范围内的ZnFe2O4单晶颗粒构成.ZnFe2O4纳米棒在室温下具有超顺磁特性.     

溶胶-凝胶法制备Li3V2 (PO4)3粉体的形貌控制研究

以LiOH·H2O,NH4VO3,H3PO4和柠檬酸为原料,十二烷基苯磺酸钠(SDBS)为表面活性剂,采用溶胶凝胶法实现了Li3V2(PO4)3粉体的制备.添加不同剂量的十二烷基苯磺酸钠(SDBS)探究其对Li3V2(PO4)3粉体物相形貌的控制作用,采用热分析、X射线衍射和场发射扫描电子显微镜对其晶型结构,形貌特征进行表征,从而研究Li3V2(PO4)3的合成温度及十二烷基苯磺酸钠(SDBS)加入量对粉体物相形貌的影响.结果表明,用溶胶凝胶法制备合成了单斜结构Li3V2(PO4)3粉体.SDBS的加入对样品的晶粒尺寸和表面形貌有一定的影响.     

镧掺杂混晶结构TiO2纳米粉体的制备及其光催化性能

以钛酸四丁酯为Ti源,采用溶胶-凝胶自蔓燃法制备了镧掺杂的La-TiO2(简写为LT)纳米粉体.利用X射线粉末衍射(XRD)、红外光谱(FIIR)、透射电子显微镜(TEM)等对掺杂型TiO2粉体的晶型结构与颗粒尺寸等进行表征.利用紫外-可见光吸收光谱(UV-vis)研究了H2O2改性、镧掺杂量以及混晶结构对TiO2纳米粉体降解甲基橙的影响.结果表明:镧掺杂混晶TiO2粉体的光催化活性明显优于未掺杂的锐钛矿TiO2粉体.当La3+掺杂量为0.5;,合成温度为475℃(金红石相含量为26.0;)时,得到的TiO2粉体光催化活性最好.H2O2的加入有助于TiO2光催化剂表面的电子-空穴对生成,提高光催化剂对甲基橙的降解率,当H2O2浓度为6;时,光照3h后,降解率达到了91.97;.     

微波辅助低温合成Bi4Ti3O12纳米晶及其性能研究

采用微波辅助低温合成了正交相铋层状结构Bi4Ti3O12 (BIT)纳米粉体.采用X射线粉末衍射(XRD)、红外光谱(IR)、扫描电子显微镜(SEM)等分析手段对粉体进行分析表征.基于电荷平衡与质量平衡理论,对络合物体系的反应平衡常数进行理论计算,确定了前驱体溶液的最佳pH值范围.然后通过改变合成工艺中溶液pH值范围、柠檬酸与硝酸根离子的配比n(CA) /n(NO3-)、热处理温度等参数,获得了BIT的优化工艺参数:溶胶pH值为6～7,柠檬酸与硝酸根离子配比为1.25:1,热处理温度为450℃,保温时间为2h时.微波辅助低温合成的粉体呈球状均匀分布,粒径在20～50 nm.相较于传统工艺,微波辅助加热处理可显著降低粉体的团聚程度和合成温度.     

柠檬酸燃烧法制备Sr3Y2(BO3)4∶Eu3+荧光粉及特性研究

以柠檬酸为络合物及助燃剂,使用简单的凝胶燃烧法,通过调整B2O3用量,制备出了不同含量Eu3+掺杂的Sr3 Y2( BO3)4基红光荧光粉.对所得样品进行了X射线衍射分析(XRD)、差热分析(DTA),扫描电镜分析(SEM)及荧光光谱分析(FDS).分析结果显示,样品的烧结温度比固相法降低了100℃,且其粉体的分散性和颗粒度都得到了改善,并且得到Eu3+最佳的掺杂浓度为12mol;.     

溶胶-凝胶法制备Y_(3-x)Ce_xAl_5O_(12)纳米粉体的研究

以Y(NO3)3.6H2O、Ce(NO3)3.6H2O、Al(NO3)3.9H2O、柠檬酸为主要原料,以聚乙二醇作为分散剂,采用溶胶-凝胶法合成了纳米级YAG∶Ce3+粉体。研究了煅烧温度、溶液中金属离子浓度、溶液pH值及Ce3+掺杂量等因素对制备纳米YAG∶Ce3+粉体的颗粒尺寸、颗粒形貌、物相的影响。结果表明:当溶液pH为=4.0、金属离子浓度为0.50 mol/L、煅烧温度为1000℃时,可以制备出具有良好的分散性,平均粒径在30 nm的粉体。     

凝胶燃烧制备中温固体电解质La0.9Sr0.1Ga0.8Mg0.2O3-δ

本文采用凝胶燃烧法制备La0.9Sr0.1Ga0.8Mg0.2O3-δ固体电解质(LSGM),讨论了溶液浓度、pH值、柠檬酸的加入量、加热温度等工艺条件对成胶的影响,X射线衍射分析表明,凝胶经1400℃煅烧10h制备得到单相粉体,制备的粉体颗粒尺寸平均为150nm.     

溶液燃烧法合成ZnxCo1-xAl2O4尖晶石型超细陶瓷色料

以Zn(NO3)2·6H2O、Co(NO3)2·6H2O、Al(NO3)3·9H2O和C12H22O11为原料,采用溶液燃烧法合成ZnxCo1-xAl2O4(0≤x≤1)尖晶石型陶瓷色料.采用X射线衍射(XRD)、扫描电子显微镜(SEM)和色度分析仪等检测方法对Zn2+的掺杂量和热处理温度对合成粉体的物相组成、微观形貌和呈色性能的影响规律进行了表征.结果表明:在Zn2掺杂量x=0.2、前驱体溶液中(Zn2++Co2+)浓度为0.3 mol/L、点燃温度400℃、后续热处理温度1200℃和保温时间30 min条件下,合成色料的蓝度值(-b*)达47.03的最大值,其平均晶粒尺寸为120 nm.     

共沉淀法制备BiFeO_3粉体

以Bi(NO_3)_3·5H_2O和Fe(NO_3)_3·9H_2O为原料,冰醋酸做溶剂,柠檬酸为络合剂,采用共沉淀法制备前驱物,对前驱物沉淀进行退火处理,制备出BiFeO_3纳米粉体.研究了煅烧温度和冰醋酸的加入量对BiFeO_3纳米粉体的晶粒尺寸及形貌的影响.采用X射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)对所制备的BiFeO_3纳米粉体进行表征,用EDS确定了样品的表面成分组成.结果表明:退火温度为450 ℃时出现BiFeO_3衍射峰,但存在杂相;退火温度为600 ℃时制备出了BiFeO_3纯相粉体,粉体为立方体结构.冰醋酸加入量由1 mL增大到1.8 mL时,粉体的晶粒尺寸由14.21 nm减小到11.65 nm.通过EDS能谱分析得出BiFeO_3粉体由Bi,Fe和O 三种元素组成.     

Triethyl ammonium salt of O,O′-bis(p-tolyl)dithiophosphate, [Et3NH]+[(4-MeC6H4O)2PS2]−

Triethyl ammonium Salt of O,O′-bis(p-tolyl)dithiophosphate and O,O′-bis(m-tolyl)dithiophosphate have been obtained by reaction of p- and m-cresol, respectively with P₂S₅ in toluene and have been characterized by elemental analysis, IR, ¹H and ³¹P NMR spectroscopy. The molecular structure of O,O′-bis(p-tolyl)dithiophosphate has been determined. Crystal data: [Et₃NH]⁺[(4-MeC₆H₄O)₂PS₂]⁻: Monoclinic, P2₁/c, a=15.2441(9) ?, b=10.415(2) ?, c=3.9726(9) ?, β=91.709(7)°, V=2217.5(1) ?⁻³, Z=4.Supplementary materials Additional material available from the Cambridge Crystallographic Data Centre (CCDC no. 600927 for [Et₃NH]⁺[(4-MeC₆H₄O)₂PS₂]⁻ comprises the final atomic coordinates for all atoms, thermal parameters, and a complete listing of bond distances and angles. Copies of this information may be obtained free of charge on application to The Director, 12 Union Road, Cambridge CB2 2EZ, UK (fax: +44-1223-336033; email: deposit@ccdc.cam.ac.uk or www:http://www.ccdc.cam.ac.uk).     

Crystal structure of Zn4Na(OH)6SO4Cl·6H2O

The structure of Zn₄Na(OH)₆SO₄Cl·6H₂O, a secondary mineral from Hettstedt, Germany, was determined by single-crystal X-ray diffraction. The crystals are hexagonal,a=8.413(8),c=13.095(24) Å, space group $P\bar 3$ , Z=2. The structure was refined to R=0.0554 and R_w=0.0903 for 970 reflections with I≥3σ(I). The structure can be described as zinc hydroxide layers perpendicular toc, from which sulfates and chlorides extend. The layers are held together by a system of hydrogen bonds involving hexaaquo Na⁺ ions which occupy the interlayer space.     

Synthesis and Crystal Structure of 5-[2-(6-bromonaphthalenyloxymethyl)]-3-(4-morpholinomethyl)-1,3,4-oxadiazole-2(3<Emphasis Type="Italic">H</Emphasis>)-thione

Abstract  The title compound, C₁₈H₁₈BrN₃O₃S, a derivative of 1,3,4-oxadiazole, crystallizes in the triclinic space group P-1 with unit cell parameters a = 6.8731(3), b = 8.9994(4), c = 15.7099(6) ?, α = 92.779(3)°, β = 130.575(3)°, γ = 107.868(4)°, Z = 2. The dihedral angle between the mean planes of the planar naphthyl and morpholine (chair) rings with the planar oxadiazol ring is 50.1(8) and 76.8(6)°, respectively. The planar naphthyl ring is twisted 52.2(5)° with the mean plane of the morpholine ring. A group of four intermolecular close contacts are observed between a bromine atom and hydrogen atoms from the closely packed naphthyl, morpholine and oxy–methyl groups in the unit cell. These molecular interactions in concert with an additional series of π–π stacking interactions that occur between the center of gravity of the two 6-membered rings of the naphthalene group influence the twist angles of each of these three groups. A MOPAC AM1 calculation of the conformation energy of the crystal structure [226.0128(9) kcal] compared to that of the minimum energy structure after geometry optimization [29.9744(1) kcal] reveals a significantly reduced value. The twist angles of the three groups above also change after the AM1 calculation giving support to the influence of both intermolecular C–H···Br short-range interactions and Cg π–π stacking interactions on these angles which therefore play a role in stabilizing crystal packing. Graphical Abstract  Crystal structure of 5-{[(6-bromonaphthalen-2-yl)oxy]methyl}-3-(morpholin-4-ylmethyl)-1,3,4-oxadiazole-2(3H)-thione, C₁₈H₁₈BrN₃O₃S, is reported and its geometric and packing parameters described and compared to a MOPAC computational calculation. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Crystal structure of irisolidone from the flowers of Pueraia lobata

Irisolidone (5,7-dihydroxy-6,4′-dimethoxyisoflavone) was isolated from the flowers of Pueraia lobata and its crystal structure was examined by X-ray single crystal diffraction. The crystal structure of irisolidone is monoclinic, space group P2₁/c with a = 15.491(9) ?, b = 7.895(4) ?, c = 13.321(7) ?, β = 110.546(9)° and Z = 4. Hydrogen bonding and aromatic π–π stacking assemble the title compound into a three-dimensional networking structure.     

Synthesis of spinacine and spinacine derivatives: crystal and molecular structures of Nπ-hydroxymethyl spinacine and Nα-methyl spinaceamine

The natural amino acid L-Spinacine (4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid) has been synthesized following a new pathway which gives a chemically and optically pure product with an excellent yield. The crystal structures of a synthetic intermediate, N^π-hydroxymethyl-spinacine, and a spinacine derivative, N^α-methyl-spinaceamine, have been investigated through X-ray diffraction: Spi(πMeOH)·H₂O, monoclinicP2 _i,a=8.571(1),b=6.682(1),c=8.588(1) Å, and β=94.67(1)^o. Spm(αMe)·2HCl·H₂O, triclinicP l,a=7.492(4),b=10.799(3),c=7.040(2) Å, α=91.88(2), β=98.36(3) and γ=73.34(3)^o. Spi(πMeOH) crystallizes with a water molecule and displays a zwitterionic character. The carboxylate group is in equatorial position and forms a short electrostatic interaction of 2.618(2) Å between one of its oxygens and the protonated nitrogen of the tetrahydropyridine ring. The crystal packing is assured by strong O?H???O, O?H???N, N?H???N intermolecular hydrogen bonds and C?H???O close contacts. The biprotonated compounds Spm(αMe) crystallizes with two Cl^? anions and a water molecule. The positive charge on the imidazole ring is delocalized on the conjugated moiety N=C?N. The crystal is built up by clusters formed by two biprotonated Spm(αMe) molecules, four Cl^? anions and two water molecules linked together by hydrogen bonds.     

X-ray Crystal Structures of [Et3NH][{(CO)5Mo(P(OCH2CMe2CH2O)O)}2H] and (CO)5Mo{μ-Ph2POPPh2}Mo(CO)5, Two Complexes Derived from the Hydrolysis of Coordinated Chloro-Phosphorous-Donor Ligands

Abstract X-ray crystal structures of [Et₃NH][{(CO)₅Mo(P(OCH₂CMe₂CH₂O)O)}₂H], 3, and (CO)₅Mo{μ-Ph₂POPPh₂}Mo(CO)₅, 2, are reported. Crystallization of 3 occurs in P-1 space group with a = 9.6944(19) ?, b = 10.814(2) ?, c = 19.730(4) ?, α = 94.24(3)°, β = 92.23(3)°, γ = 113.47(3)°, Z = 4. Crystallization of 2 occurs in C2/c space group with a = 10.357(2) ?, b = 20.149(4) ?, c = 17.155(3) ?, α = 90°, β = 97.28(3)°, γ = 90°, Z = 8. Compound 2 is a bimetallic complex with a P–O–P bridging group containing bond distances similar to that of other complexes in which two metal centers are bridged by a single R₂POPR₂ ligand. Compound 3 contains intermolecular hydrogen bonded P–O–H–O–P linkages with bond distances comparable to those seen in similar structures with intramolecular hydrogen bonding suggesting that the distance is a function of the nature of the bond and not affected by the cis arrangement of the ligands about the metal center. Graphical abstract X-ray Crystal Structures of [Et ₃ NH][{(CO) ₅ Mo(P(OCH ₂ CMe ₂ CH ₂ O) O)} ₂ H] and (CO) ₅ Mo{μ-Ph ₂ POPPh ₂ }Mo(CO) ₅ , Two Complexes Derived from the Hydrolysis of Coordinated Chloro-Phosphorous-Donor Ligands Samuel B. Owens Jr., Abha A. Kaisare and Gary M. Gray X-ray crystal structures of [Et₃NH][{(CO)₅Mo(P(OCH₂CMe₂CH₂O)O)}₂H], 3, and (CO)₅Mo{μ-Ph₂POPPh₂}Mo(CO)₅, 2, have been determined.      

Preparation,spectral studies and X-ray crystal structure of 1,3,5-triphenyl-1,5-pentanedione,C23H20O2

1,3,5-triphenyl-1,5-pentanedione, C₂₃H₂₀O₂, has been prepared and characterized by spectroscopic methods and single crystal X-ray analysis. Crystals are monoclinic, space groupP2₁/n, a=28.124(4),b=5.997(1),c=10.434(1)Å, -98.42(1)Å,Z=4. The structure has been refined to a finalR-value of 0.040 for 1625 reflections withF _o>3(F _o). The compound contains the two carbonyl groups in a mutuallycis arrangement.     

Isotope Effects in Liquid Crystal Systems: I: Phase Relationships in the Dodecylamine-H2O,Dodecylamine-D2O Systems

The phase diagrams and heats of fusion and transition have been determined for the dodecyl amine (-NH₂)/H₂O and dodecyl amine (-ND₂)/D₂O systems using direct optical observation and differential scanning calorimetry.     

Spherulitic crystallization of β‐In2Te3 by physical vapour deposition

Different morphologies of indium telluride (In₂Te₃) including novel spherulites were crystallized using the physical vapour deposition (PVD) method, by varying the difference in the growth and source zone temperature (ΔT) of a dual zone horizontal furnace assembled indigenously. Whiskers and kinked needles of In₂Te₃were grown at ΔT = 250 K and 300 K respectively, maintaining the growth zone at 500 °C. At high supersaturation (Δ T = 400 K), spherulitic crystals were obtained. The stoichiometric composition of these crystals has been confirmed using energy dispersive analysis by x‐rays (EDAX). The structure of β‐In₂Te₃ spherulitic crystals is identified as zinc blende with lattice parameter a = 6.159 Å, from x‐ray diffraction (XRD) studies. The scanning electron microscope (SEM) images revealed the radial structure of the grown spherulites. The growth mechanism for the spherulitic crystallization of β‐In₂Te₃ crystals has been discussed based on the theoretical models. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)