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以糯米浆为有机调控物质,二氧化碳提供碳源仿生制备出多种形貌的碳酸钙晶体.探索了矿化时间、钙离子浓度对碳酸钙晶体形貌和晶型的影响.采用扫描电子显微镜(SEM)、傅里叶红外光谱仪(FT-IR)和X射线衍射仪(XRD)对制备的碳酸钙表观形貌及结构进行表征.扫描电镜结果表明:以糯米浆为有机调控物质,钙离子浓度和矿化时间对碳酸钙晶体的形貌有一定的影响;XRD及FT-IR图谱表明制备的碳酸钙晶型为方解石和球霰石. 相似文献
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在碱性环境下(pH> 12)采用衬底溶液双滴加法制备了形貌均匀且长径比大于10的文石型碳酸钙晶须.探讨了衬底液浓度、温度等因素对碳酸钙晶须生长的影响;研究了硫化钠、硫酸钠、硫代硫酸钠对碳酸钙晶须生长过程的影响;通过扫描电子显微镜和X射线衍射对样品的形貌和物相进行了表征.结果表明:衬底液Ca2+浓度为0.4 mol/L、温度为80 ℃时最有利于文石型碳酸钙晶须的生长;随着含硫化合物的增加,文石型碳酸钙晶须的长径比与质量分数均逐渐减小,且方解石型碳酸钙含量逐渐增加. 相似文献
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根据生物矿化原理,通过CO2的缓慢扩散,在硫酸软骨素(CSB)/L-谷氨酸二元体系中,与富集在有机/无机界面钙离子的结合,合成了不同形貌的碳酸钙.系统地研究了室温下各种因素对碳酸钙晶体形貌和晶型的影响.产物用XRD、SEM和FT-IR进行表征,FT-IR和XRD分析表明:所得的晶体为方解石的晶型,SEM表明体系中CSB的浓度,pH值,CSB/L-谷氨酸的浓度比对碳酸钙形貌起着重要作用.通过改变实验条件得到了椭球型,哑铃型等形貌碳酸钙晶体,并对其可能的形成机理进行了分析. 相似文献
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碳酸钙有不同的晶体特征,使其在各个领域发挥不同的作用,对碳酸钙晶型、形貌和尺寸的控制是无机材料制备的研究热点。以电石渣为原料制备纳米碳酸钙能够实现变废为宝,是含钙固废综合利用的研究方向之一。因此在电石渣制备纳米碳酸钙过程中同步实现晶型、形貌的调控,能够将低附加值的电石渣固废转化为高附加值的纳米碳酸钙产品,具有良好的环境效应和经济效益。本文总结了电石渣制备纳米碳酸钙的方法,重点讨论了制备过程中晶型和形貌控制方面的研究进展。结果表明,在碳酸钙晶体成核和生长的过程中,控制工艺条件可以通过影响过饱和度进一步实现对晶型和形貌的调控,且不同种类的添加剂作用机理也不尽相同。热力学、动力学作为控制结晶各过程平衡的基础,可以用来解释各影响因素的作用机理。 相似文献
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The syntheses, properties, and structures of N-phenylmaleimidetriazole derivatives are described. Intermediates and by-products are also discussed. 1b. a = 43.997(7) Å, 5.7610(9) Å, 8.245(1) Å, = 99.339(4), C2/c; 2a. a = 13.646(4) Å, b = 7.744(2) Å, c = 10.612(3) Å, = 91.979(6), P21/c. 3a. a = 22.245(1) Å, b = 22.245(1) Å, 10.010(1) Å, P42/n. 3a. a = 11.727(2) Å, b = 14.075(3) Å, c = 16.080(3) Å, = 105.859(3), = 105.331(3), = 98.187(3), P-1. 3b. a = 8.561(3) Å, b = 14.755(5) Å, c = 22.771(7) Å, = 97.006(5), P21/c. 3c. a = 10.500(2) Å, b = 12.189(2) Å, c = 13.040(2) Å, = 109.091(3), = 106.089(3), = 101.022(3), P-1. 8a. a = 16.389(8) Å, b = 5.749(3) Å, c = 19.316(3) Å, = 97.467(9), P21/n. 8b. a = 5.822(2) Å, b = 10.114(3) Å, c = 16.705(4) Å, = 84.681(5), = 82.840(5), = 75.769(4), P-1. 9b. a = 11.251(1) Å, 13.335(3) Å, 13.376(3) Å, = 102.456(4), P21/n. 9c. a = 15.836(3) Å, b = 8.236(2) Å, c = 5.447(3) Å, = 92.551(3), P21/c. 10a. a = 13.177(2) Å, b = 14.597(2) Å, c = 5.5505(8) Å, = 110.979(2), Cc. 11a. a = 14.720(2) Å, b = 13.995(2) Å, c = 38.245(6) Å, = 94.430(3), P21/n. 12b. a = 15.067(5) Å, b = 20.378(6) Å, c = 8.669(5) Å, = 99.16(4), = 99.32(3), = 105.23(3), P-1. 13b. a = 8.2824(6) Å, b = 10.5245(7) Å, c = 15.518(1) Å, = 92.305(1), = 100.473(1), = 100.124(1), P-1. 15a. a = 15.357(3) Å, b = 7.778(2) Å, c = 22.957(2) Å, Pbca. 16b. a = 18.0384(4) Å, b = 12.474(3) Å, c = 20.078(5) Å, Pbca. 相似文献
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Using sol-gel method, mesoporous and photoluminescent silica nanocomposites of soluble starch have been synthesized and characterized. Different ratios of H2O, TEOS and EtOH were used at fixed template (soluble starch) and catalyst (NH4OH) concentrations to obtain materials of different performances in terms of heavy metal binding from a solution which has been monitored using Cd(II) as representative divalent heavy metal ion. Optimum material was obtained when H2O, TEOS and EtOH were used in 14:1:2 ratio. This sample was not only an efficient metal ion adsorbent but also had an intense luminescence in ultra-violet region and potentially may be used in silicon-based UV-emitting devices. Metal binding by the material was further enhanced after calcination (at 800 °C in air) while its luminescence had a multipeak profile in UV-visible region. In a batch adsorption study, calcined hybrid composite (0.25 g/L) could remove 98.5% Cd(II) from 100 mg/L Cd(II) solution in 2 h. The chemical, structural and textural characteristics of the synthesized materials have been investigated using Fourier Transform Infrared Spectroscopy (FTIR), X-rays Diffraction (XRD), Thermal Analysis (TGA/DTA), Photoluminescence (PL), Brunauer-Emmett-Teller Analysis (BET) and Scanning Electron Microscopy (SEM). 相似文献
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E. M. Engler R. Greene P. Haen Y. Tomkiewicz K. Mortensen J. Berendzen 《Molecular Crystals and Liquid Crystals》2013,570(1):371-380
Abstract Considerable variation in the conditions of electrochemical crystal growth of TMTSF2X (i.e., constant current versus constant potential, ambient versus inert atmosphere, etc.) and in the purity of the constituents (donor, electrolyte, solvent) does not significantly affect the unusual low-temperature properties of this class of materials. Our results suggest that the electrocrystallization procedure may be self-purifying by selecting for conducting crystal phases with constituents having specific oxidation potentials and solubility properties. However, doping solutions with structurally and chemically similar constituents (i.e., TMTTF, and IO? 4 in CIO? 4) leads to their incorporation in the crystal structure where they have a profound effect. Several mole percent of these dopants suppress superconductivity in the PF? 6 and CIO? 4 salts, and increase and broaden the metal-insulator phase transition. 相似文献
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Filiz Ercan S. Gül Öztas Nilgün Ancm Tuncer Hökelek Mürside Tüzün Dinçer Ülkü 《Journal of chemical crystallography》1996,26(3):243-247
N-trans-cinnamylidene-m-toluidine (1) C16H15N, and N-trans-cinnamylidene-m-chloroaniline (2) C15H12NCl form isomorphous crystals which are monoclinic, space group P2l/c, with unit cell dimensionsa=5.967(2),b=13.793(3),c=15.048(5) Å, =91.97(3)° anda=5.868(2),b=13.788(4),c=15.191(4) Å, =91.87(3)°, respectively. The single-crystal X-ray structure determinations of the title compounds revealtrans structures. Ring (A) C10–15 and ring (B) C1–6, are practically planar in both structures with dihedral angels of 61.3(3) and 63.6(2)°, respectively.1H nmr, u.v. and i.r. spectra are also reported. 相似文献
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Mark R. Mason Thomas S. Barnard Mawuto F. Segla Baohan Xie Kristin Kirschbaum 《Journal of chemical crystallography》2003,33(7):531-540
4-Bromophenyldi(3-methylindol-2-yl)methane (2) and 2-methoxyphenyldi(3-methylindol-2-yl)methane (3) were prepared by sulfuric-acid-catalyzed reactions of 3-methylindole with 4-bromobenzaldehyde and o-anisaldehyde, respectively. Di(3-methylindol-2-yl)phenylmethane (1) and tri(3-methylindol-2-yl)methane (4) were similarly prepared as described previously. Spectroscopic data (1H, 13C NMR) and the X-ray crystal structures for 1
C2H5OH and 2–4 are reported. The molecular structure of 1
C2H5OH shows hydrogen bonding of both indolyl NH protons to the oxygen of an ethanol molecule. Crystal data for 1
C2H5OH: Orthorhombic, Pca21, a = 23.9782(17) Å, b = 8.4437(7) Å, c = 11.3029(9) Å, V = 2288.4(3) Å3, R
1 = 0.0597. Crystal data for 2: Orthorhombic, P212121, a = 8.911(3) Å, b = 9.584(4) Å, c = 24.040(11) Å, V = 2053.0(14) Å3, R
1 = 0.0454. Crystal data for 3: Monoclinic, P21/c, a = 9.737(2) Å, b = 25.035(6) Å, c = 9.359(2) Å, = 114.853(4), V = 2070.2(8) Å3, R
1 = 0.0511. Crystal data for 4: Trigonal, R3, a = 14.2214(10) Å, c = 9.6190(10) Å, V = 1684.8(2) Å3, R
1 = 0.0425. 相似文献
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Synthesis and crystal structure of indium arsenate and phosphate dihydrates with variscite and metavariscite structure types 总被引:1,自引:0,他引:1
XueJiao Tang Maria J. Gentiletti Abdessadek Lachgar 《Journal of chemical crystallography》2001,31(1):45-50
The hydrothermal synthesis, crystal structure analysis, and spectroscopic studies of InPO4·2H2O (1) and InAsO4·2H2O (2) are reported. Compound 1 is isomorphic with metavariscite: monoclinic P21/n (No. 14), a = 5.4551(3) Å, b = 10.2293(4) Å, c = 8.8861(3) Å, = 91.489(4)°, Z = 4, and compound 2 is isomorphic with variscite: orthorhombic Pbca (No. 61), a = 10.478(1) Å, b = 9.0998(8) Å, c = 10.345(1) Å, Z = 8. Their three-dimensional frameworks are built of corner sharing InO4(H2O)2 octahedra and MO4 (M = P5+ or As5+) tetrahedra. The water molecules in both compounds have different environments and are involved in different types of hydrogen bonding. Infrared spectroscopy indicates that water molecules are true H2O species. 相似文献
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Miguel A. Mendez-Rojas Satish G. Bodige Krzysztof Ejsmont William H. Watson 《Journal of chemical crystallography》2001,31(1):17-28
A series of organosulfur compounds was characterized by NMR, IR, mass spectroscopy, cyclic voltammetry, and chemical analyses. The crystal structures of six compounds were determined: 1,3-dithioleno[4,5-e]naphtho[2,3-b]1,4-dithiin-2,5, 10-trione (1b), P
, a = 7.665(4), b = 7.997(4), c = 11.443(5) Å, = 91.311(8), = 92.516(8), = 117.53(7)° 6,7-dimethylbenzo[1,2-b]1,3-dithioleno[4,5-e]1,4-dithiin-2,5,8-trione (2b), P21/m, a = 3.933(1), b = 12.864(2), c = 11.943(3) Å, = 99.161(4)° 6-phenyl-2-thioxo-6-hydrocyclopenta[2,1-b]1,3-dithioleno[4,5-e]1,4-dithiin-5,7-dione (3a), C2/c, a = 32.408(6), b = 3.8743(8), c = 27.123(5) Å, = 125.171(7)° 6-phenyl-1,3-dithioleno[4,5-e]3-pyrrolino[3,4-b]1,4-dithiin-5,7-trione (3b), P21/n, a = 7.9712(9), b = 6.1976(7), c = 55.978(6) Å, = 91.096(1)° 2,3,7,8-tetramethylthianthrene-1,4,6,9-tetraone (4), P21/c, a = 4.195(1), b = 17.924(5), c = 9.682(3) Å, = 98.509(5)° 3H,6H-1,4-oxathiino[6,5-2,1]naphtho[3,4-e]1,4-oxathiin-2,7-dione (5), P21/n, a = 9.3522(7), b = 7.8782(6), c = 17.118(1) Å, = 93.171(1)°. Several structures exhibited significant S—S intermolecular interactions, suggesting that the molecules might be precursors for preparing nonmetallic conductors. 相似文献
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The role that disorder plays in shaping the functional form of the optical absorption spectra of both amorphous silicon and amorphous germanium is investigated. Disorder leads to a redistribution of states, which both reduces the empirical optical energy gap and broadens the optical absorption tail. The relationship between the optical gap and the breadth of the absorption tail observed in amorphous semiconductors is thus explained. 相似文献
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Floris Akkerman Jürgen Buschmann Dieter Lentz Peter Luger Eva Rödel 《Journal of chemical crystallography》2003,33(12):969-975
A single crystal of phase 1 of 1,2-difluoroethane was grown from the melt directly on an X-ray diffractometer close to the melting point of 169 K. It crystallizes in the monoclinic space group C2/c with lattice parameters a = 7.775(4), b = 4.4973(7), c = 9.024(3) Å, = 101.73(1)°, V = 308.9(2) Å3, d
calc = 1.420 g cm–3 for Z = 4. A second phase of 1,2-difluoroethane was obtained under similar conditions which crystallizes in the orthorhombic space group P212121 with the unit cell parameters a = 8.0467(16), b = 4.5086(9), c = 8.279(2) Å,V = 300.36(11) Å3, d
calc = 1.461 g cm–3 for Z = 4. In both phases the 1,2-difluoroethane molecules adopt the gauche conformation with F–C–C–F torsion angles close to 68°. Crystals of 1,2-diiodoethane C2H4I2 were grown from pentane at –30°C. A platelet single crystal of the size 0.35 × 0.25 × 0.03 mm was measured with Mo K-radiation at 153 K. 1,2-Diiodoethane crystallizes in the monoclinic space group P21/n with a unit cell of a = 4.6051(7), b = 12.939(2), c = 4.7318(7) Å, = 104.636(3)°, V = 272.79(7) Å3, Z = 2, d
calc = 3.431 g cm–3, (MoK) = 11.353 mm–1. In the molecule the two neighboring iodine atoms are positioned anti. The shortest intermolecular contacts occur via iodine–iodine interactions resulting in layers of molecules in the crystal. 相似文献