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1.
The far infrared and Raman spectra of polycrystalline 1,2-dichloroethane and 1,2-dichloroethane-d4 for the low temperature modification have been measured from 450 to 33 cm−1 at various temperatures from −100 to −182°C. Raman spectra of the high temperature crystalline modification for both samples were also investigated. The Raman data are in conflict with those previously reported. Assignments are made for the lattice vibrations in terms of the crystallographic unit cell C2h5 (P21/c) with two molecules per unit cell. The spectra of the high temperature modification are consistent with those expected for orientationally disordered crystals. 相似文献
2.
G.P. De SousaP.T.C. Freire J.A. Lima Jr.J. Mendes Filho F.E.A. Melo 《Vibrational Spectroscopy》2011,57(1):102-107
Single-crystals of l-histidine hydrochloride monohydrate, C6H9N3O2·HCl·H2O, were studied by Raman spectroscopy as a function of pressure in a diamond anvil cell up to 7.5 GPa at room temperature over the spectral range 3450-30 cm−1. The effect of changing pressure on the vibrational spectrum is discussed. From the analysis of results we inferred that the crystal undergoes a reversible structural phase transition between 2.7 and 3.1 GPa. This transition is characterized by the splitting of a band related to torsion of CO2−, the disappearance and appearance of modes related with stretching of OH− and deformation of CO2−, as well as with bands of low wavenumber which are assigned as lattice modes, and by the discontinuities of the curves of wavenumber versus pressure. Pressure coefficients for all modes observed in this work are also given. 相似文献
3.
Raman spectra of poly(tetramethyl-p-silphenylene-siloxane) were investigated in solution with depolarization ratios and in the solid state. Polarized infrared (IR) spectra were studied on oriented polymer samples. Assignments of the vibrational bands are given and IR dichroic and Raman data are in agreement with tetragonal P41 space group symmetry. These data provide information on the arrangement of the Si? C6H4? Si groups in the unit cell. On the basis of vibrational spectra the dynamic interaction between adjacent benzene rings is negligibly small and the rings preserve their local D2h Pseudosymmetry. 相似文献
4.
The luminescence spectra of Cs2MnF6 and of Mn4+ in Cs2GeF6, Cs2SiF6 and Rb2SiF6 show bands due to low frequency vibrations which are not assignable using the unit cell model. Comparison of these spectra with infrared and Raman spectra and with a model for the lattice dynamics has suggested probable assignments for the vibrational and luminescence spectra. 相似文献
5.
In this study, SrBAsO5 was synthesized by a solid state reaction using SrCO3, As2O5, and H3BO3 as reported before. The x-ray powder diffraction, FTIR, and Raman data were in agreement with the reported crystal structure. It crystallizes in a hexagonal system in P3121, and the refined unit cell parameters are a = 7.056(3) Å, c = 6.898(1) Å, and Z = 3. It is isostructural with SrBPO5. FTIR and Raman investigation of this compound were done for the first time in this study. 相似文献
6.
The infrared and Raman spectra of crystalline tetra-n-propylammonium bromide, (n-C3H7)4NBr, have been measured in the 3000 – 700 cm−1 region and vibrational assignments are proposed in part on the basis of the known crystal structure. Pressure-tuning infrared and Raman studies of this material were also undertaken using a diamond-anvil cell. There is a pressure-induced phase transition occurring between 1.8 and 2.1 GPa, which is most likely a second-order transition. Some differences are noted between the infrared data reported here and those given in an earlier high-pressure infrared study. The spectroscopic results will be useful in examining zeolites involving (n-C3H7)4NBr as a template. 相似文献
7.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1989,45(8):877-878
The i.r. and Raman spectra of KMgClSO4·3H2O and its deuterated compound KMgClSO4·3D2O have been recorded and analysed. Due to site symmetry effects the i.r. inactive modes appear as sharp bands in the i.r. spectrum. Water bands indicate strong hydrogen bonding and show the presence of three crystallographically distinct water molecules in the unit cell. 相似文献
8.
《Vibrational Spectroscopy》2010,52(2):251-254
The infrared and Raman spectra of crystalline tetra-n-propylammonium bromide, (n-C3H7)4NBr, have been measured in the 3000 – 700 cm−1 region and vibrational assignments are proposed in part on the basis of the known crystal structure. Pressure-tuning infrared and Raman studies of this material were also undertaken using a diamond-anvil cell. There is a pressure-induced phase transition occurring between 1.8 and 2.1 GPa, which is most likely a second-order transition. Some differences are noted between the infrared data reported here and those given in an earlier high-pressure infrared study. The spectroscopic results will be useful in examining zeolites involving (n-C3H7)4NBr as a template. 相似文献
9.
Two five-coordinate copper(II) complexes, formulated as [Cu(La)2Cl]BF4 (1) and [Cu(Lb)2Cl]BF4 (2) having d-(+)-1,2,2-trimethylcyclopentane-1,3-diamine (La) and d,l-1,2,2-trimethylcyclopentane-1,3-diamine (Lb) ligands, have been synthesized and characterized. X-ray diffraction studies of 1 and 2 demonstrate that they crystallize in the different space groups (P212121 for 1 and Pnma for 2), although they have identical unit cell volumes, due to the use of enantiomeric and racemic diamine ligands. One dimensional (1D) hydrogen-bond-sustained dimeric zigzag chains are formed by means of eight-membered N2H2CuBF2 as well as 10-membered N2H4ClBF2 hydrogen-bonded cycles. Thermal analyses for 1 and 2 are also described herein. 相似文献
10.
G. E. Walrafen W.-H. Yang Y. C. Chu M. S. Hokmabadi 《Journal of solution chemistry》2000,29(10):905-936
Addition of water to stoichiometric 100% sulfuric acid increases the density untila maximum results near 87 mole% H2SO4. The density and conductivity maximaand viscosity minimum, the latter two near 75 mole%, are direct macroscopicresponses to microscopic quantum mechanical properties of H3O+ and of nearlysymmetric H-bond double-well potentials, as follows: (1) lack of H bonding tothe O atom of H3O+; (2) short, 2.4–2.6 A, O—O distances of nearly symmetricH bonds; and, (3) increased mobility of protons in such short H bonds, give riseto the density maximum via (1) and (2); (1) produces the viscosity minimum;and the conductivity maximum results from (2) and (3). A pronounced minimumnear 1030 cm–1 in the symmetric SO3 stretching Raman frequency of HSO4
–,observed near 45 mole% also results from double-well effects involving the shortH bonds of direct hydronium ion—bisulfate ion pair interactions. Estimates of theconcentrations of the (H3O+)(HSO4
–) and (H2SO4)(HSO4
–) pair interactions weredetermined from Raman intensity data and are given for compositions between42–100 mole% 相似文献
11.
ATR FTIR and Raman spectra of l-Lys·HCl·2H2O and two crystalline forms of anhydrous l-Lys·HCl are reported and discussed. Distinction with earlier published IR spectra of l-Lys·HCl·2H2O registered by the KBr pellet method is explained by distortion of the spectra because of possible ionic exchange and partial decomposition. 相似文献
12.
Raman spectra of the polycrystalline l-alanine analogs CH3CH(NH+3)COO?, CH3CH(ND+3)-COO?, CD3CD(NH+3)COO?, and CD3CD(ND+3)COO? have been obtained. A normal coordinate analysis is carried out based on the experimental frequencies of the four isotopic analogs and a 34 parameter valence-type force field defined in terms of local symmetry coordinates. The final refinement, in which five stretching force constants are constrained to fixed values obtained from bond length data, results in an average error of 7 cm?1 (0.9%) for the observed frequencies of the four isotopically substituted molecules. Band assignments are given in terms of the potential energy distribution for local symmetry coordinates. For non-deuterated l-alanine, the vibrations above 1420 cm?1 and below 950 cm?1 may be described as localized group vibrations. By contrast, the eight modes in the middle frequency range, viz. the three skeletal stretching, the COO? symmetric stretching, one NH+3 rocking, the symmetric CH3 deformation, and the two methyne CH deformation vibrations, are very strongly coupled to one another. Some decoupling appears to take place in the perdeutero molecule, and all but five modes can be described as localized group vibrations. 相似文献
13.
L-cysteine hydrochloride monohydrate crystals, C3H7NO2S·HCl·H2O, were studied by Raman spectroscopy as a function of pressure in a diamond anvil cell up to 6.2 GPa in the spectral range 3500−30 cm−1. From the analysis of the results, we inferred that the crystal is structurally stable in this pressure range. Some changes on the Raman spectra were observed for bands related to vibrational modes of the SH, NH3+, CH2, CCN, OH and COH units. These modifications were associated with conformational changes of the molecules in the unit cell undergone at high pressures. Comparing this behavior with those of L-cysteine, DL-cysteine and L-cysteine hydrochloride crystals in the same pressure range, we note greater stability for the hydrochloride monohydrate form. In the L-cysteine hydrochloride monohydrate crystal, the chloride ion and water molecule play an essential role in increasing the number of the hydrogen bonds, improving the structural stability of the crystal. 相似文献
14.
S. A. Popov L. A. Glinskaya T. E. Kokina R. F. Klevtsova A. V. Shpatov 《Journal of Structural Chemistry》2011,52(3):582-588
3,5-Dimethyl-1H-pyrazolide of 3-O-acetyl ursolic acid (II) is obtained in the course of the interaction of 3 O-acetyl ursolic acid acyl chloride (I) and 3,5-dimethyl-1H-pyrazole. The crystal structure of compound II is determined from the single crystal XRD data (150 K, Bruker X8 Apex CCD autodiffractometer, MoK α radiation). The crystals are rhombic, the unit cell parameters are as follows: a = 10.6034(2) Å, b = 12.4096(2)Å, c = 24.5972(5)Å, P212121 space group. The structure consists of discrete acentric molecules. When pyrazolide II is boiled in the alcohol alkali solution, secondary hydroxyl is deacetylated and 3,5-dimethyl-1H-pyrazolide of ursolic acid IV is formed. Compounds II and IV are studied by NMR spectroscopy. 相似文献
15.
Yu. V. Pleskov S. M. Pimenov Po-Yee Lim V. G. Ralchenko 《Russian Journal of Electrochemistry》2008,44(7):861-865
Nitrogenated nanocrystalline diamond thin films are grown from arc-plasma in CH4/Ar/H2/N2-gas mixtures and characterized by AFM-and Raman spectroscopy, X-ray diffraction and resistivity measurements. It is shown by Mott-Schottky plots taken in indifferent electrolyte (0.5 M H2SO4) that the behavior of the nitrogenated nanocrystalline diamond thin-film electrodes resembles that of n-type semiconductor; the donor effective concentration therein is estimated. 相似文献
16.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1980,36(7):705-712
The i.r. (4000-30 cm−1) and Raman (4000-20 cm−1) spectra of 2,6-pyridinedicarboxylic acid C5H3N(COOH)2, C5H3N(COOD)2, 2,6-pyridine-4-d1 dicarboxylic acid and calcium dipicolinate trihydrate (the equimolar salt of calcium and 2,6-pyridinedicarboxylic acid) at 100 K have been investigated.A tentative assignment is given by referring to the isotopic frequency shifts and group frequency considerations as well as to depolarization ratios. Thirty-four internal vibrations from the 39 expected modes have been observed for the crystalline dipicolinate ion, the relevant molecular point group being C 2ν. Cyclic centrosymmetric dimeric structures involving the carboxyl groups in the acid are proposed to explain the spectral features of this compound. 相似文献
17.
T. A. Denisova L. G. Maksimova E. V. Polyakov N. A. Zhuravlev S. A. Kovyazina O. N. Leonidova D. F. Khabibulin E. I. Yur’eva 《Russian Journal of Inorganic Chemistry》2006,51(5):691-699
Features of proton-for-lithium ion substitution in monoclinic and pseudocubic lithium titanate are studied by X-ray diffraction, NMR spectroscopy, and Raman spectroscopy. Proton incorporation into the lithium titanate structure decreases the parameter a c of the pseudocubic unit cell from 8.28 Å in Li2TiO3 to =8.15 Å in H2TiO3. Metatitanic acid, like hydrous titania, has weak acid properties, but unlike titania, it sorbs hydrolyzable multicharged cations from aqueous solutions. 相似文献
18.
D. A. Köse G. Gökçe S. Gökçe İ. Uzun 《Journal of Thermal Analysis and Calorimetry》2009,95(1):247-251
Three novel mixed ligand complexes of Ni(II), Zn(II) and Cd(II) with p-chlorobenzote and N,N-diethylnicotinamide were synthesised and characterized on the basis of elemental analysis, FTIR spectroscopic
analysis, solid state UV-Vis spectrometric and magnetic susceptibility data. The thermal behavior of the complexes was studied
by simultaneous TG-DTA methods in static air atmosphere and the mass spectra data were recorded.
According to microanalytical results, formulas of complexes are C34H40N4O8ClNi, C34H40N4O8ClZn and C34H44N4O10ClCd. The complexes contain two moles of coordination waters, two moles p-chlorobenzoate and two mole N,N-diethylnicotinamide (dena) ligands per formula unit. In these complexes, the p-chlorobenzoate and N,N-diethylnicotinamide behave as monodentate ligand through acidic oxygen and nitrogen of pyridine ring.
The decomposition pathways and the stability of the complexes are interpreted in the terms of the structural data. The final
decomposition products were found to be as metal oxides. 相似文献
19.
Zusammenfassung Das Pulverdiagramm, mit welchen die Gitterkonstanten und die Raumgruppe festgestellt wurden, sowie das IR-Spektrum und eineDTA-Untersuchung von Cd(MnO4)2·6 H2O werden angegeben und kurz besprochen.X-Ray powder data, unit cell dimensions, space group, IR-spectrum andDTA data of Cd(MnO4)2·6 H2O are given and shortly discussed. 相似文献
20.
The structural roles of the two types of lattice water in K3N(SO3)3.2H2O have been determined from the geometries of their immediate environments. Through hydrogen bonds of different lengths (and hence strengths), H2O(1) links adjacent N(SO3)33?ions belonging to the same unit cell and lying on the same crystallographic mirror plane as O(1).H2O(2) links identical N(SO3)33?ions contained in unit cells adjacent in the b direction, by very weak, equivalent hydrogen bonds. The hydrogen atoms of H2O(1) are assigned to Cs sites in the unit cell and those of H2O(2) are assigned to C1 sites. The proposed site occupancies are verified by infrared spectroscopy using the “isotopic dilution” technique. 相似文献