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71.
The NIR and IR transmission spectra at room temperature of single crystals of (C2H5NH3)2PdCl4 (EAPdC) have been measured, as well as unpolarized Raman spectra at room and liquid-nitrogen temperature. These vibration spectra are compared with those of EACuC and EACdC. We conclude that EAPdC belongs to the family of compounds EAMC, where M = Mn, Cu, Cd. 相似文献
72.
N,N-Dimethylaminopropylsilane: a case study on the nature of weak intramolecular Si...N interactions
Hagemann M Berger RJ Hayes SA Stammler HG Mitzel NW 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(35):11027-11038
N,N-Dimethylaminopropylsilane H(3)Si(CH(2))(3)NMe(2) was synthesised by the reaction of (MeO)(3)Si(CH(2))(3)NMe(2) with lithium aluminium hydride. Its solid-state structure was determined by X-ray diffraction, which revealed a five-membered ring with an SiN distance of 2.712(2) A. Investigation of the structure by gas-phase electron diffraction (GED), ab initio and density functional calculations and IR spectroscopy revealed that the situation in the gas phase is more complicated, with at least four conformers present in appreciable quantities. Infrared spectra indicated a possible SiN interaction in the Si-H stretching region (2000-2200 cm(-1)), as the approach of the nitrogen atom in the five-membered ring weakens the bond to the hydrogen atom in the trans position. Simulated gas-phase IR spectra generated from ab initio calculations (MP2/TZVPP) exhibited good agreement with the experimental spectrum. A method is proposed by which the fraction of the conformer with a five-membered ring can be determined by a least-squares fit of the calculated to experimental absorption intensities. The abundance of this conformer was determined as 23.7(6) %, in good agreement with the GED value of 24(6) %. The equilibrium SiN distance predicted by theory for the gas-phase structure was highly variable, ranging from 2.73 (MP2) to 3.15 A (HF). The value obtained by GED is 2.91(4) A, which could be confirmed by a scan of the potential-energy surface at the DF-LCCSD[T] level of theory. The nature of the weak dative bond in H(3)Si(CH(2))(3)NMe(2) can be described in terms of attractive inter-electronic correlation forces (dispersion) and is also interpreted in terms of the topology of the electron density. 相似文献
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M. Csatlós A. Krasznahorkay A. M. van den Berg M. N. Harakeh S. Y. van der Werf M. Hagemann M. de Huu H. Akimune H. Fujimura M. Fujiwara K. Hara T. Ishikawa 《Acta Physica Hungarica A》2001,13(1-3):203-205
Dipole resonances have been excited in 121?124Sn isotopes using (3He,t) charge exchange reaction at E 3 He=177 MeV and the cross sections were related to the neutron-skin thicknesses. The well understood correlation may be used to determine the neutron-skin thicknesses in the future. 相似文献
79.
Barium calcium magnesium fluoride (Ba2(BaxCa1‐x)Mg4F14, x=0.19‐0.26) has been synthesized at 850 °C from precursors prepared by the solution precipitation method. Single crystals with composition of Ba2.200(2)Ca0.800(2)Mg4F14were obtained after prolonged heating. Lattice parameters from single crystal data are a = 12.4203(8) and c = 7.4365(5) Å [tetragonal, space group P42/mnm (No. 136)]. They increase with increasing barium concentration within a given stability window. The structure is built of a network of MgF6 octahedra forming a pyrochlore related channel system and isolated fluorine ions. Within the channels, heavy alkaline earth ions are located. The wide channel is filled with off‐center positioned barium ions. The channel with a narrow cross section hosts both ions, Ca2+and Ba2+. The structure is isotypic with Pb3Nb4O12F2 but has a different coordination around Ba/Ca and Pb, respectively. Doped with ∼1% Eu(II), the compound shows intense blue luminescence under UV activation. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
80.
Hagemann H. Tissot P. Lovy D. Kubel F. Bill H. 《Journal of Thermal Analysis and Calorimetry》1999,57(1):193-202
We have studied the solid-liquid equilibrium of the system Sr1–yBayFCl1–xBrx using DTA and X-ray diffraction techniques. The entire composition range in this system yields solid solutions which crystallize in the PbFCl (Matlockite) structure type. The melting points of the entire composition range have been parametrized (within 5°C rms error) using a biquadratic fit of the available data obtained by experiment and from the literature.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献