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1.
V. V. Drozdova E. A. Malinina L. V. Goeva I. N. Polyakova N. T. Kuznetsov 《Russian Journal of Inorganic Chemistry》2010,55(1):34-39
A method for the synthesis of the silver(I) complex with the closo-decaborate anion and triphenylphosphine [Ag2(Ph3P)2B10H10]
n
was developed and the structure of this complex was studied. The polymeric chain of the complex is formed with participation
of Ag(I) atoms, which coordinate the B10H102− anions through the apical (B(1)–B(2), B(9)–B(10)) and equatorial (B(3)–B(6), B(5)–B(8)) edges, the metalligand bonding occurring
through three-center two-electron bonds (MHB). The P atoms of two triphenylphosphine molecules are also incorporated in the
inner coordination sphere of the metal: the CN of the silver atom is 4 + 1. 相似文献
2.
Phase relations in
the solid state in the FeVO4–Co3V2O8
system, in the whole range of components concentration have been studied.
It was found that the composition of the phase of the howardevansite type
structure, formed in the investigated system, corresponds with the Co2.616Fe4.256V6O24 formula. The phase of the lyonsite type structure
has a homogeneity range with the Co3+1.5xFe4–xV6O24 formula (0.476 formula (0.476<x<1.667).
The melting temperature and the volume of the unit cell of the lyonsite type
structure phase increases together with the rise of cobalt quantity contained
in it. Basing on the results of the DTA and XRD measurements a phase diagram
of the FeVO4–Co3V2O8
system up to the solidus line was constructed. 相似文献
3.
Li Chen Haixia Shen Zhen Lu Cang Feng Su Chen Yanru Wang 《Colloid and polymer science》2007,285(13):1515-1520
TiO2–SiO2 composite nanoparticles were prepared by a sol–gel process. To obtain the assembly of TiO2–SiO2 composite nanoparticles, different molar ratios of Ti/Si were investigated. Polyurethane (PU)/(TiO2–SiO2) hybrid films were synthesized using the “grafting from” technique by incorporation of modified TiO2–SiO2 composite nanoparticles building blocks into PU matrix. Firstly, 3-aminopropyltriethysilane was employed to encapsulate TiO2–SiO2 composite nanoparticles’ surface. Secondly, the PU shell was tethered to the TiO2–SiO2 core surface via surface functionalized reaction. The particle size of TiO2–SiO2 composite sol was performed on dynamic light scattering, and the microstructure was characterized by X-ray diffraction and
Fourier transform infrared. Thermogravimetric analysis and transmission electron microscopy (TEM) employed to study the hybrid
films. The average particle size of the TiO2–SiO2 composite particles is about 38 nm when the molar ratio of Ti/Si reaches to1:1. The TEM image indicates that TiO2–SiO2 composite nanoparticles are well dispersed in the PU matrix. 相似文献
4.
Jianxia Jiao Qun Xu Limin Li Takano Tsubasa Takaomi Kobayashi 《Colloid and polymer science》2008,286(13):1485-1491
Titania–silica composite have been prepared using polyethylene glycol (PEG) with different molecular weights (M
w), PEG20000, PEG10000, and PEG2000, as template in supercritical carbon dioxide (SC CO2). The composite precursors were dissolved in SC CO2 and impregnated into PEG templates using SC CO2 as swelling agent and carrier. After removing the template by calcination at suitable temperature, the titania–silica composite
were obtained. The composite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and nitrogen
sorption–desorption experiment. Photocatalytic activity of the samples has been investigated by photodegradation of methyl
orange. Results indicate that there are many Si–O–Ti linkages in the TiO2/SiO2 composite; the PEG template has a significant influence on the structure of TiO2/SiO2. In addition, the TiO2/SiO2 prepared with PEG10000 exhibited high photocatalytic efficiency. So this work supplies a clue to control and obtain the TiO2/SiO2 composite with different photocatalytic reactivity with the aid of suitable PEG template in supercritical CO2. 相似文献
5.
Ya-Guang Chen Fan-Xia Meng Hai-Jun Pang Dong-Mei Shi Yu Sun 《Journal of Cluster Science》2007,18(2):396-405
A novel uranyl complex with dimeric lacunary polyoxoanion like open-mouthed clam, Na5[(A-α-SiW9O33H3)2K{UO2(H2O)}2], was prepared and characterized by elemental analysis, infrared and ultraviolet–visible spectroscopy and single crystal
X-ray diffraction. In the anion, two A-α-SiW9O3410− groups share two terminal oxygen atoms Od′ derived from removal of three corner-shared W atoms from saturated α-Keggin anion, forming a dimeric anion with an open
mouth in which potassium ion and uranyl ions are coordinated. Uranium atom adopts a pentagonal bipyramidal geometry. The coordinating
anions are linked by sodium ions via coordination of terminal or bridging oxygen atoms, forming two-dimensional layer arrangement.
Between the layers are the hydrogen bonds from which a supramolecular architecture is created. UV–VIS spectrum gives W–O and
U–O charge transfer transitions at 230–265 and 432 nm, showing the change of geometry of the polyanion and weakening of the
U–O bonds of the uranyl cation.
Electronic supplementary material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
6.
Fe3O4 nanorods and Fe2O3 nanowires have been synthesized through a simple thermal oxide reaction of Fe with C2H2O4 solution at 200–600°C for 1 h in the air. The morphology and structure of Fe3O4 nanorods and Fe2O3 nanowires were detected with powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy.
The influence of temperature on the morphology development was experimentally investigated. The results show that the polycrystals
Fe3O4 nanorods with cubic structure and the average diameter of 0.5–0.8 μm grow after reaction at 200–500°C for 1 h in the air.
When the temperature was 600°C, the samples completely became Fe2O3 nanowires with hexagonal structure. It was found that C2H2O4 molecules had a significant effect on the formation of Fe3O4 nanorods. A possible mechanism was also proposed to account for the growth of these Fe3O4 nanorods.
Supported by the Fund of Weinan Teacher’s University (Grant No. 08YKZ008), the National Natural Science Foundation of China
(Grant No. 20573072) and the Doctoral Fund of Ministry of Education of China (Grant No. 20060718010) 相似文献
7.
Daixin Ye Yanhong Xu Liqiang Luo Yaping Ding Yulong Wang Xiaojuan Liu 《Journal of Solid State Electrochemistry》2012,16(4):1635-1642
A novel electrochemical sensor based on LaNi0.5Ti0.5O3/CoFe2O4 nanoparticle-modified electrode (LNT–CFO/GCE) for sensitive determination of paracetamol (PAR) was presented. Experimental
conditions such as the concentration of LNT–CFO, pH value, and applied potential were investigated. Under the optimum conditions,
the electrochemical performances of LNT–CFO/GCE have been researched on the oxidation of PAR. The electrochemical behaviors
of PAR on LNT–CFO/GCE were investigated by cyclic voltammetry. The results showed that LNT–CFO/GCE exhibited excellent promotion
to the oxidation of PAR. The over-potential of PAR decreased significantly on the modified electrode compared with that on
bare GCE. Furthermore, the sensor exhibits good reproducibility, stability, and selectivity in PAR determination. Linear response
was obtained in the range of 0.5 to 901 μM with a detection limit of 0.19 μM for PAR. 相似文献
8.
L. G. Bulusheva A. V. Okotrub V. V. Bashilov V. I. Sokolov 《Russian Chemical Bulletin》2005,54(12):2730-2734
The electronic structure of the (η2-C60)Pd[P(Ph2)C5H4]2Fe complex was calculated by the “hybrid” B3LYP method. Comparison of the experimental X-ray emission C-Kα spectrum and theoretical
spectrum of the compound demonstrated that the electron interactions between the C60 core, palladium atom, and organometallic fragment are described correctly in the framework of the quantum chemical method
used. The electronic structure of the organometallic fullerene complex can be presented as a set of blocks of orbitals corresponding
to different types of chemical bond.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2640–2644, December, 2005. 相似文献
9.
Atmospheric plasma sprayed alumina–titania (Al2O3–13%TiO2), coated on stainless steel (XC18), were characterized. The coating structure and morphology were studied by scanning electron
microscopy. Their presented micro cracks, laminar splats. The coatings were studied by X-ray diffraction. The main phase transformation
is that of α-Al2O3 into metastable γ-Al2O3. The α-Al2O3 phase is due to the occurrence of partially melted particles Electrochemical behaviours of coatings were mainly investigated
by potentiodynamic polarization and electrochemical impedance spectroscopy in 0.01 M [K3Fe(CN)6/K4Fe(CN)6] as a function of process parameters. Also, schematic equivalent circuit was proposed. The results were expected to facilitate
the understanding and improvement of the coating behaviours. 相似文献
10.
Marcin Środa 《Journal of Thermal Analysis and Calorimetry》2009,97(1):239-243
Glasses have been synthesized in the system SiO2–Al2O3–Na2O–AlF3–LaF3–Er2O3. A base glass (in mol% 67SiO2–9Al2O3–20Na2O–Al2F6–3La2F6) was modified by 0.5, 0.75, 1, 1.25, 1.5, 2 and 5 mol% Er2O3, respectively. Glasses were prepared by conventional fusion method from 20 g batches. The glass transition temperature (T
g), the jump-like changes of the specific heat (ΔC
p) accompanying the glass transition and the enthalpy of crystallization (ΔH) were calculated. DTA measurements clearly reveal that the increase of the Er2O3 content in the glass changes the effects of crystallization and diminishes the thermal stability of the glassy network. In
the same time the changes in the transition temperature are observed. The formation of NaLaF4 and Na1.45La9.31(SiO4)6(F0.9O1.1) as a main phase was confirmed. The diminishing of the thermal stability was connected with erbium which incorporated into
Na1.45La9.31(SiO4)6(F0.9O1.1) structure. 相似文献
11.
Carrying out crystallization studies for both Se0.95In0.05 and Se0.90In0.10 chalcogenide glasses under non-isothermal conditions at different heating rates, it was realized that a rate controlling
process occurs where random nucleation of one- to two-dimensional growth is accompanied with the introduction of up to 10 at%
In into glassy Se matrix. The crystallization kinetics together with its dimensionality has been studied using the four currently
used isoconversional models (Kissinger–Akahira–Sunose, Ozawa–Flynn–Wall, Tang, and Starink). The activation energy of crystallization
(E
c) has been determined using these indicated four models where a satisfactory concurrence is achieved. The value of E
c shows a decrease while increasing both the In-content as well as the extent of crystallization. 相似文献
12.
Magdalena Szumera Irena Wacławska Zbigniew Olejniczak 《Journal of Thermal Analysis and Calorimetry》2010,99(3):879-886
Glasses of the SiO2–P2O5–K2O–MgO–CaO–B2O3 system acting as nutrients carriers in the soil environment were synthesised by the melt-quenching technique. Thermal properties
were studied using DTA/DSC methods and the influence of B2O3 and P2O5 content on thermal stability and crystallization process of these glasses was examined. The structure of the glass network
was characterized by FTIR, 31P, and 11B MAS NMR. The chemical activity of the glasses in the 2 mass% citric acid solution was measured by the ICP-AES method. The
analysis indicated that the formation of P–O–B units with chemically stable tetrahedral borate groups decreases the glass
solubility in conditions simulating the soil environment. 相似文献
13.
M. Chromčíková M. Rodová K. Nitsch M. Liška 《Journal of Thermal Analysis and Calorimetry》2010,102(3):961-964
Structural relaxation of scintillating Ce-doped Na–Gd phosphate glass with a nominal composition of Ce:NaGd(PO3)4 was experimentally studied using non-isothermal thermo-mechanical analysis, and the relaxation process was described by the
Tool–Narayanaswamy–Mazurin model. The distribution of relaxation times was expressed by the empirical Kohlrausch–Williams–Watts
relaxation function with relaxation time directly proportional to dynamic viscosity. The model parameters and material constants
were obtained by the nonlinear regression analysis of thermo-mechanical data. It has been concluded that the model used of
structural relaxation correctly describes relaxation processes in studied Ce-doped NaGd(PO3)4 glass. 相似文献
14.
I. V. Bodnar’ 《Russian Journal of Inorganic Chemistry》2010,55(6):835-840
Homogeneous MnIn2S4 single crystals ∼14 mm in diameter and ∼40 mm long were grown by directional solidification of melt. For these MnIn2S4 single crystals, the composition was determined by electron probe microanalysis, structure by X-ray diffraction, and melting
temperature by differential thermal analysis. Transmission spectra were studied in these single crystals, in the region of
the intrinsic absorption edge within 10–300 K. The transmission spectra were used to determine the bandgap width, and it was
plotted as a function of temperature. The thermal expansion of MnIn2S4 single crystals was studied dilatometrically in the range 80–700 K, and the thermal expansion coefficient was determined. 相似文献
15.
Stephen D. Williams Timothy J. Johnson Thomas P. Gibbons Christopher L. Kitchens 《Theoretical chemistry accounts》2007,117(2):283-290
The accuracy of various computational methods (Hartree–Fock, MP2, CCSD, CAS-SCF, and several types of DFT) for predicting
relative intensities in Raman spectra for C6H6, C6D6, and C6F6 was compared. The predicted relative intensities for ν1 and ν2 were compared with relative intensities measured by an FT-Raman spectrometer. While none of these methods excelled at this
prediction, Hartree–Fock with a large basis set was most successful for C6H6 and C6D6, while PW91PW91 was the most successful for C6F6. 相似文献
16.
Tim Dinges Rolf-Dieter Hoffmann Leo van Wüllen Paul Henry Hellmut Eckert Rainer Pöttgen 《Journal of Solid State Electrochemistry》2011,15(2):237-243
The lithium-rich silicide Li4Pt3Si was synthesised from the elements by high-temperature synthesis in a sealed niobium ampoule. Its structure was refined
on the basis of single-crystal X-ray diffraction data: R32, a = 693.7(2), c = 1627.1(4) pm, wR2 = 0.0762, 525 F2 values and 21 variables. The striking structural motifs of the Li4Pt3Si structure are silicon atoms with a slightly distorted trigonal prismatic platinum coordination with short Si–Pt distances
(238–246 pm). Always two trigonal prisms are condensed via a common Pt3 triangle, and these double units built up a three-dimensional network by condensation via common corners. The channels left
by this prismatic network are filled by two crystallographically independent lithium sites in a 3:1 ratio. The single crystal
X-ray data were fully confirmed by neutron powder diffraction and 7Li magic-angle spinning (MAS)–nuclear magnetic resonance (NMR) results. The two distinct lithium sites are well differentiated
by their 7Li isotropic chemical shift and nuclear electric quadrupolar interaction parameters. MAS-NMR spectra reveal signal coalescence
effects above 300 K, indicating chemical exchange between the lithium sites on the millisecond timescale. The spectra can
be simulated with a simple two-site exchange model. From the resulting temperature-dependent correlation times, an activation
energy of 50 kJ/mol is extracted. 相似文献
17.
The reactions of [RuCl2(PPh3)3] with 8-hydroxy-2-methyl-quinoline-7-carboxylic acid was examined, and a novel ruthenium(II) complex—[Ru(PPh3)2(C5H8NO)2]—was obtained. The compound was studied by IR, UV–vis spectroscopy, and X-ray crystallography. The molecular orbital diagram
of the complex was calculated with the density functional theory (DFT) method. The spin-allowed singlet–singlet electronic
transitions of the compound were calculated using the time-dependent DFT method, and the UV–vis spectrum of the compound was
discussed, on this basis. The luminescence property of the [Ru(PPh3)2(C5H8NO)2]was examined. 相似文献
18.
Electrical conductivity in the monoclinic Li2TiO3, cubic Li1.33Ti1.67O4, and in their mixture has been studied by impedance spectroscopy in the temperature range 20–730 °C. Li2TiO3 shows low lithium ion conductivity, σ300≈10–6 S/cm at 300 °C, whereas Li1.33Ti1.67O4 has 3×10–8 at 20 °C and 3×10–4 S/cm at 300 °C. Structural properties are used to discuss the observed conductivity features. The conductivity dependences
on temperature in the coordinates of 1000/T versus loge(σT) are not linear, as the conductivity mechanism changes. Extrinsic and intrinsic conductivity regions are observed. The change
in the conductivity mechanism in Li2TiO3 at around 500–600 °C is observed and considered as an effect of the first-order phase transition, not reported before. Formation
of solid solutions of Li2–
x
Ti1+
x
O3 above 900 °C significantly increases the conductivity. Irradiation by high-energy (5 MeV) electrons causes defects and the
conductivity in Li2TiO3 increases exponentially. A dose of 144 MGy yields an increase in conductivity of about 100 times at room temperature.
Electronic Publication 相似文献
19.
O. S. Oleneva T. A. Shestimerova A. V. Olenev E. V. Dikarev A. V. Shevelkov 《Russian Chemical Bulletin》2007,56(10):1948-1952
New double mercury silver phosphide iodide Hg12Ag41P88I41 (1) was synthesized and its crystal structure was established. Compound 1 crystallizes in the cubic system. The characteristic feature of the crystal structure 1 is the presence of the anionic cage clusters P11
3−, which have been previously found in alkali metal compounds only. The well-ordered P11
3− clusters form a system of polyhedra, which encapsulate various disordered α-AgI-type fragments.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1882–1886, October, 2007. 相似文献
20.
Xiangzhong Ren Yingkai Jiang Peixin Zhang Jianhong Liu Qianling Zhang 《Journal of Sol-Gel Science and Technology》2009,51(2):133-138
One-dimensional (1D) submicron-belts of V2O5 have been prepared by a sol–gel route using V2O5, H2O2 and aniline as starting materials. Thermogravimetric and differential thermal analysis, X-ray diffraction, Fourier transform
infrared spectroscopy and scanning electron microscopy were employed to characterize the samples. Electrochemical behaviors
as cathode material in rechargeable lithium-ion batteries were investigated by galvanostatic charge–discharge measurement
and cyclic voltammeter. The results showed that the synthesized V2O5 appeared to be submicron-belts and orthorhombic structure. The V2O5 submicron-belts exhibited a high initial discharge capacity of 346 mAh/g and stayed 240 mAh/g after 20 cycles at 0.1 C discharge
rate in the potential region 1.8–4.0 V. 相似文献