共查询到20条相似文献,搜索用时 31 毫秒
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YU Yang LIU Dan HU Wei-wei LI Jia PENG Yu ZHOU Qi YANG Fen LI Guang-hua SHI Zhan FENG Shou-hua 《高等学校化学研究》2012,28(2):186-190
Three metal molybdate hydrates,Fe(H2O)2(MoO4)2·H3O(FeMo),NaCo2(MoO4)2(H3O2)(CoMo)and Mn2(MoO4)3·2H3O(MnMo),were synthesized by the mixed-solvent-thermal methods and characterized by singlecrystal X-ray... 相似文献
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层状嵌锂多元过渡金属氧化物具有比容量高、循环性能好、价格便宜、环境友好等优点,是近年来国内外能源界研究热点之一。其中,Ni、Co、Mn三元复合体系(LiNixCo1-x-yMnyO2)安全性能十分优良,在中小型储能和动力电池方面有着广阔的应用前景,广受学术和产业界的关注。 相似文献
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《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1990,46(11):1629-1638
The infrared absorption spectra of the series MF2·4H2O (M = Fe, Co, Ni or Zn) and of the respective deuterates were recorded at 296 and ∼ 100 K in the 1200-400 cm−1 wavenumber region. Using the known ZnF2·4H2O structure as a model, the number of i.r. active librations and MF2 vibrations was predicted with the aid of a group theoretical treatment. The librations were distinguished from the MF2 and MO vibrations and assigned, using isotopic ratios and correlations between the unit cell volumes, the uncoupled OH and OD stretch vibrations of HDO and the twisting libration. The six librations are assigned to two types of water molecules with low symmetry and with different hydrogen bond strengths, and are compatible with an orthorhombic Pca21 structure. The v1 and v3 intramolecular MF2 vibrations are assigned, using ZnF2·4H2O crystal data and matrix-isolated v1 and v3 (v1.3) values as guide. Shifts of v1.3 and v1/v3 relative to the matrix-isolated values suggest smaller MF bond lengths. The shifts in the values of v1.3 and v1/v3 upon deuteration and lowering of the temperature indicate smaller MF bond lengths and FMF angles. 相似文献
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Shilov G. V. Nikitina Z. K. Dobrovolskii Yu. A. Leonova L. S. Chernyak A. V. Tarasov V. P. Atovmyan L. O. 《Russian Journal of Coordination Chemistry》2004,30(11):759-764
Single crystals of the Rb4H2I2O10· 4H2O were synthesized for the first time and studied by X-ray diffraction analysis. The crystals are monoclinic, a = 7.321(6) Å, b = 12.599(8) Å, c = 8.198(8) Å, = 96.30(7)°, Z = 2, space group P21/c. The H2I2O10
4– anion is formed by the edge-sharing IO6 octahedra. The anions are united by hydrogen bonds into a chain running along the x axis. The chains are combined by water molecules into a three-dimensional structure through hydrogen bonds. The compound is a proton conductor. The conductivity values measured at 20–60°C vary within 10–6 to 10–4 ohm–1 cm–1. 相似文献
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A new borophosphate compound with the composition (NH4) χ Mn((3?χ)/2)(H2O)2 [BP2O8]·(1?x)H2O was prepared under mild hydrothermal conditions and characterized by X-ray powder diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) methods. The title compound was synthesized from MnCl2·2H2O, H3BO3, and (NH4)2HPO4 with variable molar ratios by heating at 180 °C for 7 days in an autoclave. The X-ray diffraction data of the water insoluble polycrystalline powder was indexed using the TREOR program in hexagonal system with the unit cell parameters of a = 9.5104, c = 15.7108 Å, Z = 6 and the space group P65 (No.176). (NH4) χ Mn((3?χ)/2)(H2O)2 [BP2O8]·(1?x)H2O is isostructural with (NH4) χ M ((3?χ) 2)/II (H2O)2 [BP2O8]·(1?x)H2O (MII = Co, Cd, Mg; x = 0.5–1). Its unit cell parameters and hkl values were in good agreement with the other isostructural compounds. This is the first report presenting both the synthetic details and the indexed X-ray powder diffraction pattern of this compound along with the characterization by FTIR, thermal gravimetric analysis, scanning electron microscopy and EPR. 相似文献
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A novel Mn4 mixed salt, {[(n-Bu4N)(ClO4)2]2[Mn4O6(Tacn)4](ClO4)} · 2H2O (I) and its analogue [Mn4O6(Tacn)4](ClO4)4 · 2H2O (II) (Tacn = 1,4,7-triazacyclononane), have been constructed and structurally characterized by X-ray crystallography. The [Mn4O6]4+ core of these two complexes presents an adamantine-like skeleton. Each Mn atom of both complexes is coordinated by three nitrogen atoms of Tacn and connects other Mn atoms through a single-oxo bridge in an octahedral environment. Two complexes crystallize in monoclinic crystal system, space group C2/c with a = 24.296(11) Å, b = 10.986(5) Å, c = 32.746(15) Å, β = 101.975(6)°, Z = 8 for I and space group P21/n with a = 21.141(10), b = 11.306(5), c = 21.576(10) Å, β = 111.155(5)°, Z = 4 for II. 相似文献
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Wenhui Yuan Xiaofang Hu Li Li College of Chemical Engineering Energy South China University of Technology Guangdong Key Laboratory of Green Chemicals Guangzhou China 《天然气化学杂志》2006,15(1):58-62
Single-phase perovskite La0.6Sr0.4Co0.8Fe0.2O3-δ has been successfully prepared by using citrate-EDTA complexation method at relatively low calcination temperature. The structure and thermal decomposition process of the complex precursor have been investigated by means of differential scanning calorimetry-thermal gravimetric analysis (DSC/TGA), X-ray diffraction (XRD), and Fourier transform infrared spectroscopic (FT-IR) measurements. The precursor decomposed completely and started to form perovskite-type oxide above 420℃ according to the differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results. Single-phase perovskite La0.6Sr0.4Co0.8Fe0.2O3-δ obtained has been confirmed from the XRD pattern, and no peak of SrCO3 was found by XR.D of the oxides synthesized at a relatively low temperature of 800 ℃. The reducibility of La0.6Sr0.4Co0.8Fe0.2O3-δ was also characterized by the temperature programmed reduction (TPR) technique. Disk shaped dense La0.6Sr0.4Co0.8Fe0.2O3-δ membrane was prepared by the isostatical pressing method. The oxygen flux rate of dense La0.6Sr0.4Co0.8Fe0.2O3-δ membrane was (2.8-18)×10-8 mol/(cm2·s) in the temperature range of 800-1 000℃. 相似文献
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Abdülhadi Baykal Nermin Kasapoğlu Yüksel Köseoğlu Ali Cemil Başaran Hüseyin Kavas Muhammet S. Toprak 《Central European Journal of Chemistry》2008,6(1):125-130
A series of Ni-doped cobalt ferrites NixCo1−xFe2O4 (x = 0.0, 0.4, 0.6, 0.8, and 1.0) were prepared using microwave-induced combustion. Nickel, cobalt, and ferric nitrates were
used as starting materials and glycine as fuel. The influence of Ni content on the lattice parameter, stretching vibrations,
and magnetization was studied. XRD, FTIR, and SEM were used for structure, composition, and morphology investigation. A porous
network structure was observed with average particle size 60–67 nm. All samples had a cubic spinel structure. The unit cell
parameter “a” decreases linearly with nickel concentration due to the smaller ionic radius of nickel. Magnetization measurements
showed that coercivity decreased as Ni content increased; it increased with decreasing temperature.
相似文献
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Sm0.5Sr0.5Co0.4M0.6O3 (M=Co,Mn, Fe)作为IT-SOFCs阴极的结构与性能 总被引:1,自引:0,他引:1
通过X射线衍射(XRD)、热重、热膨胀、电导率以及交流阻抗等测试方法, 研究了Sm0.5Sr0.5Co0.4M0.6O3(M=Co, Mn, Fe; 分别简写为SSCC, SSCM, SSCF)作为中低温固体氧化物燃料电池(IT-SOFCs)阴极的结构与性能. 研究表明, 固相法合成的Sm0.5Sr0.5Co0.4M0.6O3均为正交钙钛矿型结构, 材料的结构参数和性能都与M元素半径及M—O的键能有关. 晶胞参数随着Co、Mn、Fe的顺序增大.材料的氧空位浓度、热膨胀系数、电导率、电极催化活性随着Co、Fe、Mn的顺序降低. 同时由于SSCM较低的氧空位浓度, 使得电极反应受到氧在电极内的扩散过程控制, 具有较差的电极催化性能, 而SSCC和SSCF较高的氧空位浓度, 电极反应同时受到电极表面氧还原反应和氧离子在电极中的扩散过程混合控制. 由于SSCF具有较高的氧扩散系数, 使得700 ℃以上SSCF电极表面氧还原电阻(ASR)也低于SSCC的, 因而出现了SSCF的总电极催化活性高于SSCC的现象. 相似文献
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《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1991,47(2):243-253
The infrared spectra of the series MF2·4X2O (M = Fe, Co, Ni, Zn; X = H, D) are reported in the frequency ranges of the bending vibrations of the water molecules (ν2) at 296 and ∼100 K and the MO lattice vibrations (νMO) at 296 K. Four νMO vibrations consisting of two doublets are identified using deuterium substitution. The various νZnO vibrations correlate well with the metal-oxygen distances R(ZnO), and this correlation is further used to calculate R(MO)'s of the remainder of the series and to refine R(ZnO). Four ν2(H2O, HDO, D2O) vibrations, consisting of two sharp overlapping bands flanked by two broad shoulders, are identified. The number of ν2(H2O) components, the sequence of ν2 in the series and the correlation with R(MO) suggest that the ν2 frequencies are mainly determined by R(MO). Using this assignment the two types of ν2 bands are assigned to the two types of crystallographically distinct water molecules found in the MF2·4H2O structure. 相似文献
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《Journal of Coordination Chemistry》2012,65(11):967-973
Reaction of a freshly prepared Ni(OH)2?2 x (CO3) x ·yH2O with maleic acid in H2O at room temperature afforded [Ni(H2O)6][Ni(H2O)2(C4H2O4)]·4H2O, which consists of [Ni(H2O)6]2+ cations, [Ni(H2O)2(C4H2O4)]2? anions and lattice H2O molecules. Ni atoms in cations are octahedrally coordinated and Ni atoms in anions are each octahedrally coordinated by bidentate chelating maleato ligands and two water molecules at trans positions. Cations and anions are interlinked by hydrogen bonds to form 1D chains, which are hexagonally arranged and connected by the lattice water molecules. When heated in a flowing argon stream, the compound decomposes, with complete dehydration being followed by dissociation of nickel maleate into NiO and maleic anhydride. 相似文献
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Ting-Feng Yi Chun-Yan Li Yan-Rong Zhu Jie Shu Rong-Sun Zhu 《Journal of Solid State Electrochemistry》2009,13(6):913-919
Spinel LiNi0.5Mn1.5O4 and LiMn1.4Cr0.2Ni0.4O4 cathode materials have been successfully synthesized by the sol–gel method using citric acid as a chelating agent. The structure
and electrochemical performance of these as-prepared powders have been characterized by X-ray diffraction (XRD), scanning
electron microscopy (SEM), and the galvanostatic charge–discharge test in detail. XRD results show that there is a small Li
y
Ni1-y
O impurity peak placed close to the (4 0 0) line of the spinel LiNi0.5Mn1.5O4, and LiMn1.4Cr0.2Ni0.4O4 has high phase purity, and the powders are well crystallized. SEM indicates that LiMn1.4Cr0.2Ni0.4O4 has a slightly smaller particle size and a more regular morphological structure with narrow size distribution than those
of LiNi0.5Mn1.5O4. Galvanostatic charge–discharge testing indicates that the initial discharge capacities of LiMn1.4Cr0.2Ni0.4O4 and LiNi0.5Mn1.5O4 cycled at 0.15 C are 129.6 and 130.2 mAh g−1, respectively, and the capacity losses compared to the initial value, after 50 cycles, are 2.09% and 5.68%, respectively.
LiMn1.4Cr0.2Ni0.4O4 cathode has a higher electrode coulombic efficiency than that of the LiNi0.5Mn1.5O4 cathode, implying that Ni and Cr dual substitution is beneficial to the reversible intercalation and de-intercalation of
Li+. 相似文献
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《Journal of Coordination Chemistry》2012,65(21):3420-3437
Two Cu(II) hydroxo succinates [Cu3(H2O)2(OH)2(C4H4O4)2]?·?4H2O (1) and [Cu4(H2O)2(OH)4(C4H4O4)2]?·?5H2O (2) and one Cu(II) hydroxo glutarate [Cu5(OH)6(C5H6O4)2]?·?4H2O (3) have been prepared and structurally characterized by single crystal X-ray diffraction methods. They feature 1D and 2D copper oxygen connectivity of elongated {CuO6} octahedra in “4?+?1?+?1” and “4?+?2” coordination geometries. Within 1, linear trimers of three edge-sharing {CuO6} octahedra are connected into copper oxygen chains, which are bridged by the anti conformational succinate anions to generate 2D layers with mono terminally coordinating gauche succinate anions on both sides. The layers are assembled into a 3D framework by interlayer hydrogen bonds with lattice H2O molecules distributed in channels. Different from 1, the principal building units in 2 are linear tetramers of four edge-sharing {CuO6} octahedra. The tetramers are condensed into copper oxygen chains and the succinate anions interlink them into a 3D framework with triangular channels filled by lattice H2O molecules. The {CuO6} octahedra in 3 are edge-shared to form unprecedented 2D inorganic layers with mono terminally coordinating glutarate anions on both sides. Interlayer hydrogen bonding interactions are responsible for supramolecular assembly of the layers into a 3D framework with lattice H2O molecules in the channels. The inorganic layers in 3 can be described as hexagonal close packing of oxygen atoms with the Cu atoms in the octahedral cavities. The title compounds were further characterized by elemental analyses, IR spectra and thermal analyses. 相似文献
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《Journal of solid state chemistry》1987,66(2):304-310
The three-component systems RbClMnCl2H2O, 2RbCl · CoCl2 · 2H2O2RbCl · CuCl2 · 2H2OH2O, 2RbCl · CoCl2 · 2H2O2RbCl · MnCl2 · 2H2OH2O have been studied at 25°C. In the 2RbCl · CoCl2 · 2H2O2RbCl · CuCl2 · 2H2OH2O system, a discontinuous series of mixed crystals is formed and in the 2RbCl · CoCl2 · 2H2O2RbCl · MnCl2 · 2H2OH2O system, a continuous series is present.The unit cell parameters of the 2RbCl · CoCl2 · 2H2O double salt were determined: a = 5.586(2) Å, b = 6.469(3) Å, c = 6.988(2) Å, α = 65.31(3)°, β = 87.69(3)°, γ = 84.65(4)°, volume 228.4 Å3, Z = 1.The results obtained and discussed in conjunction with the crystal structure data suggest that for 2MICl · MIICl2 · 2H2O type salts the triclinic structure is stable only when the large rubidium and cesium ions participate in combinations with non-Jahn-Teller metal(II) ions. In the cases of Jahn-Teller metal(II) ions or with potassium or ammonium ions a tetragonal structure is always stable. 相似文献
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K. I. Turte S. G. Shova F. A. Spatar M. D. Mazus T. I. Malinovskii 《Journal of Structural Chemistry》1994,35(2):248-255
Results of X-ray structural analysis, IR spectroscopy, and quantum chemical study of the [Fe3O(CH3COO)6(H2O)3]NO3·4H2O complex are reported. The crystal belongs to the monoclinic system with a=15.688(3), b=11.767(2), c=15.318(4) Å, γ=92.54(3)o, space group P21/a, R=0.078. The molecule has a trinuclear structure: three iron atoms occupy the vertices of an equilateral, triangle with
an Fe−Fe distance of 3.29 Å and are bonded by the μ3-oxo and μ-CH3COO− (O,O′) ligands. To each iron atom, one water molecule is coordinated. Using the obtained values of populations on 3d AO of
Fe (d
xy
1.34
; d
xz
1.39
; d
yz
1.46
;
;
) and charges on oxygen atoms (O
c
−0.5
; O
ac
−0.31
; O
w
−0.31
), we estimated the values of isomeric shift and quadrupole splitting (0.75 and 0.70 mm/sec, respectively; these are close
to the experimental values of 0.75 and 0.58 mm/sec, (300 K)).
Institute of Chemistry, Moldovian Academy of Sciences. Moldovian State University. Institute of Applied Physics, Moldovian
Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii., Vol. 35, No. 2, pp. 112–120, March–April, 1994.
Translated by T. Yudanova 相似文献