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511.
Mn3O4的溶剂热法制备及晶粒生长动力学研究 总被引:2,自引:0,他引:2
非化学计量M n3O4-δ由八面体的M n2O3-δ相与四面体的M nO相组成,结构中的氧空位是其催化活性中心[1]。M n3O4-δ用途广泛,其高催化活性可用于环保领域分解去除废气中的CO、N2O、NO与NH3等气体或从废气中去除有机物等[2~4],高纯四方相M n3O4-δ纳米晶适用于制作软磁性材料如高 相似文献
512.
The effects of antimony modifying additive (0.15—0.50 at.% Sb) on the electrophysical and sorption properties of SnO2 powders with a well developed specific surface were studied in the temperature range of 25—250 °C. Small amounts of antimony (0.15 at.%) increase the conductivity of SnO2 containing SO2 and CO chemisorbed in the temperature range of 25—100 °C. This makes this composition promising as a sensitive element of gas sensors. 相似文献
513.
L. A. Zemnukhova R. L. Davidovich G. A. Fedorischeva 《Russian Chemical Bulletin》1994,43(10):1736-1737
The temperature dependence of the frequencies of121Sb nuclear quadrupole resonance in the spectra of M2Sb2SO4F6 (M = K, Rb, NH4) was studied in the temperature range from 77 to 340 K. A secondary phase transition was found above 320 K for (NH4)2SO4F6.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1831–1833, October, 1994.This study was sponsored by the Russian Foundation for Basic Research (Grant No. 93-03-4394). 相似文献
514.
Several cerium(III) complexes with lacunary polyoxotungstates -B-XW9O9–
33 (X=AsIII, SbIII) and W5O6–
18, have been synthesized and characterized by single-crystal X-ray analysis, elemental analysis and IR spectroscopy. The X-ray analysis of Na25[Ce(H2O)5As4W40O140]63H2O (1) reveals the framework of the well-known [As4W40O140]28– anion with a {Ce(H2O)5}3+ unit in the central site S1. The anion in (NH4)19[(SbW9O33)4{WO2(H2O)}2Ce3(H2O)8(Sb4O4)]48H2O (2) consists of a tetrahedral assembly of four -B-SbIIIW9O9–
33 units connected by two additional six-coordinate tungsten atoms, three nine-coordinate monocapped square-antiprismatic cerium atoms and a Sb4O4 cluster. The CeIII center in the [Ce(W5O18)2]9– anion in Na9[Ce(W5O18)]NaCl30H2O (3) displays the square-antiprismatic environment observed in all complexes of the type [Ln(W5O18)2]
n–. 相似文献
515.
Terrier C. Chatelon J.P. Roger J.A. Berjoan R. Dubois C. 《Journal of Sol-Gel Science and Technology》1997,10(1):75-81
The antimony doping in SnO2 thin films prepared by the sol-gel dip-coating method has been studied using two characterization techniques. In order to determine the actual doping level directly in the deposited layers, X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) have been used. We found that this doping level is systematically lower than expected from the starting solutions composition, and that two oxidation states are present: Sb3+ and Sb5+. As the antimony content increases, there is a competition between Sb5+ and Sb3+ species.The SnO2: Sb thin films have also been observed by transmission electron microscopy (TEM), showing that the measured mean size of crystallites decreases as the Sb content increases in the oxide. No precipitates of either Sn or Sb oxides (other than SnO2) could be detected. 相似文献
516.
The compound CsAgSb4S7 has been synthesized by the reaction of the elements in a Cs2S3 flux at 773 K. The compound crystallizes in a new structure type with eight formula units in space group C2/c of the monoclinic system in a cell at 153 K of dimensions , , , β=97.650(1)°, and . The structure contains two-dimensional layers separated by Cs atoms. Each layer is built from edge-sharing one-dimensional and chains. Each Ag atom is tetrahedrally coordinated to four S atoms. Each Sb3+ center is pyramidally coordinated to three S atoms to form an SbS3 group. CsAgSb4S7 is insulating with an optical band gap of 2.04 eV. Extended Hückel calculations indicate that the band gap in CsAgSb4S7 is dominated by the Sb 5s and S 3p states above and below the Fermi level. 相似文献
517.
I. A. Kyuntsel 《Journal of Structural Chemistry》2005,46(5):924-926
The temperature dependence of the 35Cl NQR frequencies and spin-lattice relaxation times has been investigated for a trigonal-bipyramidal vn complex SbCl3·NH2C6H5. Thermally activated motion of chlorine atoms (pseudorotation) was not revealed in the complex, in contrast to the vπ complexes of SbCl3 with related molecular structures. The high potential barrier of pseudorotation in the aniline complex is likely to be due to the unusually high nonequivalence of Sb-Cl chemical bonds. 相似文献
518.
A dependence between the quadrupole coupling constants (e
2
Qq
zz
) and the asymmetry parameters of the electric field gradient (η) for the antimony atoms in the complex [SbF5]2− anions of M2SbF5 pentafluoroantimonites (M=Na, K, Rb, Cs, NH4, Ti, and Et2NH2) was revealed from the123Sb NQR spectra at 77 K.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1988–1990, October, 1998. 相似文献
519.
Antimony(V) is volatilized by reaction with potassium bromide in concentrated sulfuric acid media. After volatilization, the gases can be transported to an inductively coupled plasma spectrometer for atomic emission of antimony and its analytical determination. The influent factors, concentrated sulfuric acid volume, concentration and volume of the potassium bromide aqueous solution and carrier gas flow were investigated and optimized using different alternatives. A detection limit of 48 ng ml−1 of Sb was achieved under the optimized conditions with a precision of 7.6% and the calibration graph was linear from 0.10 to 10.0 μg ml−1 for a sample injection of 130 μl.The study of interferences from common cations and anions revealed a good tolerance for most ions, although there was a significant improvement in Sb(V) volatility when As(III) was present. Furthermore, the As(III) sensitization was only produced with Sb(V) species, while the volatility of the Sb(III) bromide species was unaltered.The method was applied to the determination of Sb in real river waters. The results were checked using alternative atomic spectroscopy methods. 相似文献
520.
Zhefeng Fan 《Mikrochimica acta》2005,152(1-2):29-33
A sensitive and simple method for flame atomic absorption spectrometry (FAAS) determination of antimony species after separation/preconcentration
by cloud point extraction (CPE) has been developed. When the system temperature is higher than the cloud point extraction
temperature, the complex of antimony (III) with N-benzoyl-N-phenyhydroxylamine (BPHA) can enter the surfactant-rich phase,
whereas the antimony (V) remains in the aqueous phase. Antimony (III) in surfactant-rich phase was analyzed by FAAS and antimony
(V) was calculated by subtracting of antimony (III) from the total antimony after reducing antimony (V) to antimony (III)
by L-cysteine. The main factors affecting the cloud point extraction, such as pH, concentration of BPHA and Triton X-114,
equilibration temperature and time, were investigated systematically. Under optimized conditions, the detection limits (3σ)
were 1.82 ng mL−1 for Sb(III) and 2.08 ng mL−1 for Sb(total), and the relative standard deviations (RSDs) were 2.6% for Sb(III) and 2.2% for Sb(total). The proposed method
was applied to the speciation of antimony species in artificial seawater and wastewater, and recoveries in the range of 95.3–106%
were obtained by spiking real samples. This technique was validated by means of reference water materials and gave good agreement
with certified values. 相似文献