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1.
A comparative study of a 600 W capacitively coupled microwave plasma (CMP) operated with different plasma gases (Ar, N(2) and air) with respect to the achieved detection limits for Fe, Cr, Zn, Ca and Mg have been carried out. Radially and axially resolved rotational temperatures (T(rot)), excitation temperatures (T(exc)) and electron number densities (n(e)) of these plasmas have been determined using OH (T(rot)), Fe (T(exc)) and Mg (n(e)) as thermometric species. The influence of different gas flow rates on T(rot), T(exc) and n(e), and of Li as an easily ionized element on T(exc) has been investigated.  相似文献   

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This paper reports the formation and characterization of large (Ar) n , (N2) n , and mixed binary (Ar) n (N2) m van der Waals clusters produced at room temperature in the process of supersonic expansion. The average cluster size is determined by the buffer gas induced beam-broadening technique. For both Ar and N2 clusters, power variations of the average cluster size with the gas stagnation pressure P 0 give size scaling as . The average cluster sizes of argon vary from 2950 to more than 30900 atoms per cluster with the argon gas stagnation pressures ranging from 4 to 14 bars, and of nitrogen vary from 600 to more than 10400 molecules per cluster with the nitrogen gas stagnation pressures ranging from 8 to 38 bars. The mixed binary (Ar) n (N2) m cluster is produced by supersonic expansion of an Ar–N2 mixture. The large mixed binary (Ar) n (N2) m clusters with the average sizes n + m between 1000 and 16000 are obtained. In coexpansion of Ar–N2 mixture, we find that the argon concentration becomes higher in the beam than before the expansion. This finding is discussed and may be helpful for further insight into the phenomenon of clustering.  相似文献   

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This contribution presents the results of a single crystal X-ray diffraction study of three ammine complexes of bivalent platinum and palladium: [Pt(NH3)4](N03)2, [Pd(NH3)4](N03)2 and [Pd(NH3)4]F2H2O. The first two compounds are isostructural; metal atoms are located on inversion centers, all other atoms are in general positions. A three-dimensional framework is built from planar-square complex cations and nitrate ions joined by N-H...O hydrogen bonds. In [Pd(NH3)4]F2H2O, palladium atoms, as in the previous cases, are located on inversion centers, while oxygen atoms of water molecules are on the two-fold symmetry axis. A network of strong N-H...F and O-H...F hydrogen bonds linking the cations, anions, and crystallization water molecules is present in the structure.  相似文献   

6.
Crystal structures of Pb(MoO2)2(PO4)2 and Ba(MoO2)2(PO4)2 were determined. Both compounds contain the molybdyl group MoO2. The monoclinic unit-cell parameters are a = 6.353(7), b = 12.289(4), c = 11.800 Å, β = 92°56(6), and Z = 4 for the lead salt and a = 6.383(8), b = 7.142(7), c = 9.953(8) Å, β = 95°46(8), and Z = 2 for the barium salt. P21c is the common space group. The R values are respectively R = 0.027 and R = 0.031 for 1964 and 1714 independent reflections. The frameworks built up by a three-dimensional network of monophosphate PO4 and molybdyl MoO2 groups are similar, characterized mainly by corner-sharing PO4 and MoO6 polyhedra. Two oxygen atoms of each MoO6 group are bonded to the molybdenum atom only as in other molybdyl salts.  相似文献   

7.
The reactions of (CO2)2 and (SO2)2 with Ba have been investigated using a crossed beam arrangement and the laser-induced fluorescence technique. Internal energy in the BaO product was probed in order to study differences between monomeric and dimeric reactions. The reaction cross section for the dimers of CO2 was found to be between four and eightfold larger than that of the monomers. This can be explained by the change in the reaction mechanism due to the positive electron affinity of the dimers versus the negative electron affinity of the monomers. The product BaO from the dimeric reactions is much colder rotationally than in the monomeric case. This phenomenon can be explained based on the kinematics.  相似文献   

8.
The reactions of lanthanide tris(borohydrides) Ln(BH4)3(thf)3 (Ln = Sm or Nd) with 2 equiv. of lithium N,N′-diisopropyl-N′-bis(trimethylsilyl)guanidinate in toluene produced the [(Me3Si)2NC(NPri)2]Ln(BH4)2Li(thf)2 complexes (Ln = Sm or Nd), which were isolated in 57 and 42% yields, respectively, by recrystallization from hexane. X-ray diffraction experiments and NMR and IR spectroscopic studies demonstrated that the reactions afford monomeric ate complexes, in which the lanthanide and lithium atoms are linked to each other by two bridging borohydride groups. The complexes exhibit catalytic activity in polymerization of methyl methacrylate. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 441–445, March, 2007.  相似文献   

9.
The title compound was synthesized by reaction of Cu(ClO4)2, picolinic acid and carbamide in C2H5OH/CH3CN solution, and characterized by single-crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group Pbca with a=14.0481(8), b=9.0130(5), c=18.626(1)?, V=2358.3(2)?3Z=4, Dx=1.771g·cm-3, μ=1.235mm-1 and F(000)=1276. The final R factor is 0.0440 for 1434 observed reflections. The X-ray analysis revealed that the copper(Ⅱ) atom is coordinated by two picolinic ligands in the equatorial plane, while the two oxygen atoms of perchlorate occupy the axial positions of octahedron with lengthened Cu-O distances, resulting in a 4+2 elongated octahedral environment. In the compound, there also exist two protonated carbamide cations for charge balance. CCDC: 195354.  相似文献   

10.
Specific heat data on (BA)2Cu(Ox)2 and (CHA)2Cu(Ox)2·H2O below 1 K are reported (BA = C6H5 CH2NH3+, CHA = C6H3+, Ox = C2O42). The magnetic contributions have the form of broad maxima, occurring near 0.15. A λ-type anomaly is observed for (BA)2Cu(Ox)2 at Tc = 0.116(3) K. For (CHA)2Cu(Ox)2·H2O no such ordering is seen.(BA)2Cu(Ox)2 appears to be a quadratic S = 1/2 Heisenberg antiferromagnet with J/k = ?0.145 (3) K. The compound (CHA)2Cu(Ox)2·H2O shows a behaviour that is in between 1-D and 2-D S = 1/2 Heisenberg antiferromagnetism.  相似文献   

11.
Molecular beam deflection studies on (CO2)2 and (OCS)2 indicate that both these species are polar molecules. Structural implications of this are explored in light of previous studies of these systems.  相似文献   

12.
The complexes [Rh(η3-C3H4R)(η5-C5R′5)L]+BF4- (R  1-Me, R′  H, Me; R  2-Me, R′  H) (L  C5H5N, Ph3P, Ph3As) have been prepared from Rh(η3-C3H4R)(η5-C5R′5)Cl and AGBF4 in acetone, followed by reaction with the stoicheiometric quantity of L. The 1H and 13C NMR spectra of the salts are reported and discussed.  相似文献   

13.
The observed difference in transition strength for (SF6)2, (SiF4)2 and (SiH4)2 IR-predissociation spectra is explained by induction effects (μ012/R126) which have to be included in the interaction Hamiltonian in addition to the dominant dipole-dipole term (μ012/R123).  相似文献   

14.
The reactivity of bis(dimethylamido) complexes of phenyl- and hydridogallium with ammonia, dimethylamine and 1,1-dimethylhydrazine is described. Synthesis of the starting gallium hydride, [HGa(NMe2)2]2, was achieved in nearly quantitative yield from the reaction of HGaCl2(quinuclidine) with LiNMe2. In neat ammonia or methylamine at room temperature both dimethylamido ligands in [HGa(NMe2)2]2 were substituted by a single equivalent of NH3 or MeNH2 to produce amorphous (HGaNH)n or (HGaNMe)n, respectively. In contrast, the reaction of [PhGa(NMe2)2]2 with neat Me2NNH2, at room temperature consumed two equivalents of the substituted hydrazine to form [PhGa(NHNMe2)2]2 in a 73% yield. Single crystal X-ray crystallographic analyses of [HGa(NMe2)2]2 and [PhGa(NHNMe2)2]2 establish that in the solid state both compounds adopt a cyclic Ga-N-Ga-N structure with a crystallographic center of symmetry located at the center of the ring.  相似文献   

15.
Compound [Ni(hmt)2(SCN)2(H2O)2][Ni(SCN)2(H2O)4](H2O)2 (hmt=hexamethylenetetramine) was pre-pared and structurally characterized by means of X-ray single crystal diffraction. The two neutral units [Ni(hmt)2(SCN)2(H2O)2] and [Ni(SCN)2(H2O)4] are joined together through hydrogen bonds N…H-O, O…H-O and S…H-O. In the solid state, the compound has three-dimensional network structure. The determination of its variable-temperature magnetic susceptibilities (5~300K) shows that the magnetic behavior obeys the Curie-Weiss law over the whole temperature ranges.  相似文献   

16.
Thermal degradation of the cluster compound Os3(CO)8(PPh2H)(μ3-S)2 (I) at 125°C leads to decarbonylation and formation of the new ligand bridged hexanuclear cluster Os6(CO)14(μ-PPh2)23-S)34-S) (II) in 11% yield. Space Group: P1, No. 2, a 10.427(5), b 13.552(3), c 17.919(3) Å, α 84.87(2), β 75.41(3), γ 78.43(3)°, V 2399(2) Å3Z = 2, ?calc 2.82 g cm?3. The structure was solved by the heavy atom method and refined (3223 reflections) to the final residuals R = 0.042 and Rw = 0.036. The molecule consists of two sulfido bridged open triosmium clusters which are linked by a bridging sulfido ligand and a bridging diphenylphosphino ligand.  相似文献   

17.
Phase equilibria in the Ba3(VO4)2-K2Ba(MoO4)2 and Pb3(VO4)2-K2Pb(MoO4)2 systems have been investigated. In the first system, a continuous series of substitutional solid solutions with the palmierite structure is formed, and in the second one, the polymorphic transition in lead orthovanadate at 100°C restricts the extent of the palmierite-type solid solution to 10–100 mol % K2Pb(MoO4)2. Original Russian Text ? V.D. Zhuravlev, Yu.A. Velikodnyi, A.S. Vinogradova-Zhabrova, A.P. Tyutyunnik, V.G. Zubkov, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 10, pp. 1746–1748.  相似文献   

18.
[(ZrO2)0.92(Y2O3)0.08]0.9(TiO2)0.1 (titania-doped yttria stabilized circonia, 10TiYSZ) samples were prepared by solid state reaction from mixtures of 8 mol% yttria-doped ZrO2 (YSZ) and TiO2 and characterized in terms of structure, microstructure, and electrical properties. [(ZrO2)0.97(Y2O3)0.03]0.9(TiO2)0.1 (titania-doped tetragonal zirconia polycrystalline, 10TiTZP) was also prepared for comparison in some specific studies. Ionic transport properties were measured by impedance spectroscopy in air as a function of temperature. DC techniques including electromotive force (EMF) and Ion Blocking measurements (IB) were carried out in order to determine the electronic contribution to the total conductivity. The addition of titania to YSZ induces the tetragonal zirconia phase formation, thus [(ZrO2)0.92(Y2O3)0.08]0.9(TiO2)0.1 is a composite material and is constituted by two solid solutions, titania-doped yttria-stabilized zirconia (67.7 mole fraction) and titania-doped tetragonal zirconia (32.3 mole fraction). A decrease in bulk ionic conductivity, of one order of magnitude, when TiO2 is added to YSZ is observed in the whole temperature range. Furthermore, in the bulk conductivity vs the reciprocal of the temperature plot, a bending (from 550°C to higher temperatures) toward higher activation energies was detected. The bending could indicate the existence mainly of Ti4+-Vö associated pairs with an association energy of 0.43±0.02 eV. It could mean that Ti-O bonds become stronger and shorter and could produce the formation of microdomains of a ZrTiO4-like structure. The addition of titanium is effective in increasing the electronic conductivity under reducing conditions. Conductivity as a function of Po2 and IB results cannot be related to the formation of small polarons during the reduction process. Furthermore, according to the calculations based on the small polaron theory, inconsistent values for the radius of a small polaron (rp) are obtained in both 10TiYSZ and 10TiTZP. However, large polarons can explain the transport properties in these materials under reducing conditions in agreement with the experimental data.  相似文献   

19.
The molecular structure of [Zr(NMe2)4]2 has been determined by an x-ray study and shown to involve a central Zr2N8 moiety involving the fusing of two trigonal bipyramidal units along a common axial-equatorial edge. The terminal Zr---NMe2 units have trigonal planar coordination about the nitrogen atoms: Zr---N = 2.050(5) and 2.104(5) Å, and Zr---N (bridge) = 2.224(3) and 2.453(4) Å for equatorial and axial bonds, respectively. The Zr---Zr distance is 3.704(1) Å as expected for a non-M---M bonding bridged compound. In tetrahydrofuran solution, Zr(NMe2)4 and LiNMe2 react irreversibly giving Zr(NMe2)6 Li2(THF)2 which has been isolated and characterized by an X-ray study. The central ZrN6 octahedral moiety is capped on two opposite faces by Li atoms which are also coordinated to an oxygen atom of a THF molecule. Pertinent distances are: Zr---N = 2.22(7) (av.), N---Li = 2.155(25) (av.) and Li---O = 1.915(10) Å.  相似文献   

20.
A three-dimensional (3D) cobalt phosphate: Co5(OH2)4(HPO4)2(PO4)2 (1), has been synthesized by hydrothermal reaction and characterized by single-crystal X-ray diffraction, thermogravimetric analysis, and magnetic techniques. The title compound is a template free cobalt phosphate. Compound 1 exhibits a complex net architecture based on edge- and corner-sharing of CoO6 and PO4 polyhedra. The magnetic susceptibility measurements indicated that the title compound obeys Curie-Weiss behavior down to a temperature of 17 K at which an antiferromagnetic phase transition occurs.  相似文献   

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