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1.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1981,37(11):985-990
The i.r. spectra of some aluminates of rhomboedral and orthorhombic perovskite types are presented and analysed. The complete vibrational analysis of NdAlO3 is presented and a force field is proposed for this type of compounds; the potential energy distribution is given and the normal modes are drawn using ORTEP program. 相似文献
2.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1982,38(9):997-1003
The i.r. and Raman spectra of compounds Cd2IIB2VO7 and A2IIB2VO6 (A Ag, Tl; B Ta, Nb, Sb) belonging to the pyrochlore structure were studied. A normal coordinate analysis permitted us to calculate and to compare their force field (and also for Na2Sb2O6) which is discussed. 相似文献
3.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1980,36(8):739-744
Polarized i.r. reflection spectra for a single crystal and absorption spectra for a powder of dihydrated potassium fumarate K2C4H2O4, 2H2O are reported in the 400–3500 cm−1 region.The existence of CH ⋯ O bonds is established and the three force constants of these bonds are calculated. 相似文献
4.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1978,34(2):123-127
Raman spectroscopy of the PO3F2− ion and the Raman polarized spectra of monoclinic single crystals have been used for the determination and the attribution of the normal vibrations of the single crystal (NH4)2PO3F, H2O.The temperature dependence of the external modes supports the evidence of X-ray data that there is a decrease, at low temperature, of the distance between the anion and cation groups. 相似文献
5.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1979,35(8):937-948
The i.r. and Raman spectra of the niobate and tantalate of “1 × 2 block” type structure AIIBV2O6 (AII = Ca, Sr, Ba, Pb) are presented and analyzed. The complete vibrational analysis of BaNb2O6 is presented and a force field is proposed for this type of compounds, the potential energy distribution is given and some characteristic normal modes are drawn in comparison with the normal modes of the double octahedron B2O10 which is the basic motif of the “1 × 2 block” type structure. 相似文献
6.
Sbai K. Atibi A. Charaf A. Radid M. Jouini A. 《Journal of Thermal Analysis and Calorimetry》2002,69(2):627-645
We have studied the dehydration and the calcination under atmospheric pressure of cyclotriphosphate tetrahydrate of nickel and sodium, NiNa4(P3O9)2·6H2O, between 25 and 700°C by thermal analyses (TG, DTA) infrared spectrometry and X-ray diffraction. This study allows us the identification and the crystallographic characterization of a new phase, NiNa4(PO3)6, obtained between 350 and 450°C. NiNa4(PO3)6 crystallizes in the triclinic system, P–1, with the following unit cell parameters a=6.157(3) Å, b=6.820(6) Å, c=10.918(6) Å, =80.21(5)°, =97.80(9)°, =113.49(3)°, V=409.8 Å3, Z=1, M(19)=25 and F(19)=48 (0.0095; 42). The calcination of NiNa4(PO3)6, between 500 and 600°C, leads to a mixture of long-chain polyphosphates NiNa(PO3)3 and NaPO3. The kinetic characteristics of the dehydration of NiNa4(P3O9)2·6H2O were determined and discussed. The vibrational spectrum of the title compound, NiNa4(P3O9)2·6H2O, was interpreted in the domain of the stretching vibrations of the P3O9 rings, on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P3O9 ring with D3h symmetry.
This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
7.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1979,35(9):1029-1032
Infrared and Raman spectra in the liquid state of 3-R, 4-X cyclohexenes (R = CH3, (CH3)3C; X = CN,Cl) and their d1-(4) and d3-(3,6,6) isotopic modifications, Raman spectra of some low temperature crystallised compounds, vibrational spectra in the solid state of cis and trans 1-acetoxy 3-t-butyl 4-cyano cyclohexenes, were studied.The frequencies of cyclohexenic skeleton modes below 900 cm−1 and the frequencies of deformation modes involving the CCN bond or stretching νCCl vibration of the different conformers were assigned. In the cis and trans 1-acetoxy 3-R 4-cyano cyclohexenes (respectively in the e′a and e′e conformations), the positions of the 627 cm−1 δax and the 538 cm−1 δeq deformation vibrations agree with the assignments proposed for the other cyano derivatives. 相似文献
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9.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1978,34(10):1009-1017
The infrared and Raman spectra of β phase of H2C2O4, H2C218O4, D2C2O4, D2C218O14 and HDC2O4 isotopic species have been investigated at various temperatures (300-30 K) in the 4000-50 cm− range. All the expected (K = 0) lattice modes have been assigned and the amplitudes of R′x and R′z librations have been calculated. An assignment for 17 intramolecular fundamentals out of the 18 expected is given. Most of these internal modes show a relatively strong correlation field splitting. The structure of the OH and OD stretching bands is discussed in some detail using the isotope and temperature shifts and the isotopic dilution technique. 相似文献
10.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1990,46(3):339-354
Raman and infrared spectroscopic studies of Br(CO)4CrCCHD2 allowed a precise assignment of the vibrational frequencies and we confirmed the assignment of the vibrational frequencies of the Br(CO)4CrCR (RCH3, CH2D, CHD2 and CD3) series. The force field of the Br(CO)4CrCR series was determined by a Normal Coordinates Analysis. 相似文献
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《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1988,44(5):471-477
The i.r. and Raman spectra of room temperature phase (phase II) of (NH4)3H(SO4)2 and (ND4)3D(SO4)2 as polycrystalline samples and single crystals have been investigated between 4000 and 30 cm−1. An assignment of internal and external modes is given in terms of group frequencies and symmetry types. This crystal contains non-centrosymmetric dimers (SO4HSO4)3− where sulphate ions are associated by strong asymmetric OH … O hydrogen bonds; they are characterized by two strong Raman bands at 1078 and 966 cm−1, and a νOH frequency at about 1250 cm−1. The acidic proton is statistically disordered around the crystallographic symmetry centre while all of the NH+4 ions show an important dynamical orientational disorder. 相似文献
13.
Kacem Sbai Khadija El Kababi et Mohamed Hliwa 《Phosphorus, sulfur, and silicon and the related elements》2013,188(4):957-971
The dehydration of CuK 4 (P 3 O 9 ) 2 .4H 2 O was investigated, between 25 and 700°;C, by TG-DTA, x-ray diffraction, and IR. It leads, at 500°;C, to a mixture of long chain polyphosphates KPO 3 and CuK 2 (PO 3 ) 4 which remains stable until its melting point. The kinetic characteristics of the dehydration of CuK 4 (P 3 O 9 ) 2 .4H 2 O were determined and discussed. The vibrational spectrum of the title compound, CuK 4 (P 3 O 9 ) 2 .4H 2 O, was interpreted in the domain of the stretching vibrations of the P 3 O 9 rings on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P 3 O 9 ring with the idealized D 3h symmetry. 相似文献
14.
《Annales de Chimie Science des Materiaux》2001,26(5):57-61
Synthesis and characterization of a new oxyvanadate Bi6PbV4O20 and of Bi6Pb((P1−xVx)O4)O4 solid solutions. The anion substitution of (PO4)3− by (VO4)3− groups in the Bi6Pb(PO4)4O4 oxyphosphate led to solid solutions of Bi6Pb((P1−xVx)O4)4O4 compositions and to a new Bi6PbV4O20 oxyvanadate. The study by X-ray diffraction was used to define the limits of the solid solution. The substitution of (PO4)3− by (VO4)3− groups result in a displacement of the IR absorption bands to lower frequencies. 相似文献
15.
Marin N. Krzton A. Koch A. Robert D. Weber J. V. 《Journal of Thermal Analysis and Calorimetry》1999,55(3):765-772
The part I of this work discusses the potentialities and limits of the in situ spectroscopic analysis of cellulose by Diffuse
Reflectance Infrared Fourier Transform in an environment device. In this paper, we describe: the in situ evolutions of cellulose
from 25 to 270°C under N2 or air; the evolution of a partially thermolyzed cellulose residue during thermal treatment from 25 to 450°C and finally
the oxidation in air of a cellulose char at 300°C. We observe a limited evolution of the cellulose below 270°C. Only some
carbonyle groups issued from rearrangement of cellulose chains are formed. The thermal treatment of the thermolyzed residue
leads to a progressive aromatization of the solid between 270 and 450°C. The oxidation in air induces the formation of oxygenated
groups (carbonyles, carboxylic acids, lactones) and proceeds by reaction on both aliphatic and aromatic sites. Some dehydration
of carboxylic groups to anhydrides are observed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
《Journal of Inorganic and Nuclear Chemistry》1976,28(5):985-987
The phase diagram of the system (1 − s) Li0·5Ga2·5O4−s CuGa2O4 has been established by quenching, DTA, X-ray diffraction at high temperature and IR spectrometry. The change from the disordered (space group P4332) to the ordered cubic form (space group Fd3m) is made by means of an extensive biphase (0·25 ⩽ s ⩽ 0·52). The thermal stability of copper and mixed gallates has been studied by thermogravimetric analyses. The spectrum of Cu2+ in spinels (0·8–2·5 μ, s ⩾ 0·54) discloses copper on A and B sites. The cation distribution is deduced from neutron diffraction. 相似文献
17.
Kacem Sbai Azzeddine Atibi Saïd Belaaouad Mohamed Moutaabid 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2345-2362
We have studied the dehydration and the calcination under atmospheric pressure of cyclotriphosphate hexahydrate of nickel and silver, NiAg 4 (P 3 O 9 ) 2 ·;6H 2 O, between 25 and 600°;C by infrared spectrometry, x-ray diffraction, thermal analyses TGA, and DTA. This study led us to the identification and the crystallographic characterization of a new phase, NiAg 4 (PO 3 ) 6 , obtained between 250 and 350°;C. NiAg 4 (PO 3 ) 6 crystallizes in the triclinic system, P m 1 , with the following unit cell parameters a = 6.100(2)Å, b = 6.783(1)Å, c = 10.764(2)Å, f = 78.66(3)°;, g = 96.85(3)°;, n = 113.36(2)°;, Z = 1, V = 401Å 3 , M(20) = 133, and F(30) = 88 (0.0017; 197). The calcination of NiAg 4 (PO 3 ) 6 , between 400 and 500°;C, leads to a mixture of long-chain polyphosphates NiAg(PO 3 ) 3 and AgPO 3 . The kinetic characteristics of the dehydration of NiAg 4 (P 3 O 9 ) 2 ·;6H 2 O were determined and discussed. The vibrational spectrum of the title compound, NiAg 4 (P 3 O 9 ) 2 ·;6H 2 O, was interpreted in the domain of the stretching vibrations of the P 3 O 9 rings, on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P 3 O 9 ring with the idealized D 3h symmetry. L'étude de la déshydratation et de la calcination, sous pression atmosphérique, du cyclotriphosphate de nickel tétra-argent, NiAg 4 (P 3 O 9 ) 2 ·;6H 2 O, a été effectuée, entre 25 et 600°;C, par spectrométrie IR, diffraction des rayons x, ATG, et ATD. Elle a permis l'identification et la caractérisation cristallographique d'une nouvelle phase, NiAg 4 (PO 3 ) 6 , obtenue entre 250 et 350°;C. NiAg 4 (PO 3 ) 6 cristallise dans le système triclinique, de groupe d'espace P m 1 avec Z = 1. Les paramètres de maille sont: a = 6.100(2)Å, b = 6.783(1)Å, c = 10.764(2)Å, f = 78.66(3)°;, g = 96.85(3)°;, n = 113.36(2)°;, V = 401Å 3 et les facteurs de mérite sont: M(20) = 133, et F(30) = 88 (0.0017; 197). La calcination du composé, entre 400 et 500°;C, conduit au mélange de polyphosphates à chaînes infinies NiAg(PO 3 ) 3 et AgPO 3 . Les caractéristiques cinétiques de la déshydratation de NiAg 4 (P 3 O 9 ) 2 ·;6H 2 O ont été déterminées et discutées. Le spectre IR du sel étudié a été interprété, dans le domaine des vibrations de valence des cycles, sur la base de la structure cristalline connue de son isotype NiNa 4 (P 3 O 9 ) 2 ·;6H 2 O et de nos résultats de calcul des fréquences IR fondamentales du cycle P 3 O 9 3 m de symétrie idéale D 3h . 相似文献
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