scholarly journals Infrared and Raman spectra of liquid and crystalline silicon tetrafluoride

1970 ◽  
Vol 48 (3) ◽  
pp. 410-416 ◽  
Author(s):  
F. Bessette ◽  
A. Cabana ◽  
R. P. Fournier ◽  
R. Savoie

The Raman and infrared spectra of liquid and crystalline SiF4 have been recorded. The assignment of some of the Raman bands of the crystal to longitudinal modes has been confirmed by the infrared reflection spectrum. These indicate that the crystal structure is not centrosymmetric. In other respects the spectra are also more complicated than is expected on the basis of the previously reported Td3 structure. Possible explanations are discussed.

1992 ◽  
Vol 291 ◽  
Author(s):  
Charles C. Kim ◽  
M. I. Bell ◽  
D. A. McKeown

ABSTRACTThe normal modes of vibration and their frequencies are calculated for benitoite, a mineral whose crystal structure (space group D23h) consists of three-membered silicate rings (Si3O9) linked by Ba+2 and Ti+4 ions. The calculation unambiguously assigns the normal modes to the lines in the Raman and infrared spectra and determines the atomic interactions. On the assumption that mode mixings and splittings due to inter-ring interactions are small, the normal frequencies of the isolated ring of C3h, symmetry are determined. The identification of normal modes characteristic of three-membered silicate rings may prove to be a valuable guide in the interpretation of the infrared and Raman spectra of amorphous silicates, potentially leading to new information on the ring statistics of these materials.


1971 ◽  
Vol 49 (14) ◽  
pp. 2459-2462 ◽  
Author(s):  
R. Savoie ◽  
M. Pézolet

The Raman and far-infrared spectra of crystalline cyanogen iodide have been recorded. High-frequency shoulders alongside the Raman bands confirm the piezoelectric nature of this solid and allow an estimate to be made of the frequencies of the longitudinal modes associated to the fundamental vibrations. Dipole derivatives calculated from these frequencies agree qualitatively with those obtained from infrared band intensity measurements.


1984 ◽  
Vol 39 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Robert Becker ◽  
Wolfgang Brockner ◽  
Herbert Schäfer

Pb2P2Se6 crystallizes in the monoclinic system, space group Pn (No. 13) with the lattice constantsa = 974.2 (4) pm. b = 766.2 (3) pm. c = 689.8 (3) pm, β=91.44(5)°.The title compound is isotypic to the homologous Pb2P2S6. In the structure there are discrete P2Se4-6 anions.Far infrared, infrared and Raman spectra of this compound have been recorded. The observed frequencies are assigned on the basis of P2Se4-6 units with C2h symmetry in the crystal. DTA-data have been determined and interpreted.


1986 ◽  
Vol 41 (8) ◽  
pp. 958-970 ◽  
Author(s):  
Ralf Steudel ◽  
Jürgen Steidel ◽  
Torsten Sandow

AbstractThe homocyclic S11 and S13 molecules have been synthesized from titanocenepentasulfide and S6Cl2 or S8Cl2, respectively, and obtained as yellow crystals which are metastable for several days at 20 °C. X-Ray structural analyses of single crystals at -105± 5 °C exhibited molecules of approximately C2 symmetry with bond distances (d), bond angles (a) and torsional angles (r) in the following ranges: S11 : d = 203.2 -211.0 pm, α = 103.3-108.6°, τ = 69.3 - 140.5°; S13: d = 197.8 - 211.3 pm, α = 102.8-111.1°, τ = 29.5 - 116.3°. Infrared and Raman spectra of S11 and S13 are reported. In addition, the synthesis of S6Cl2 and S8Cl2 from S6 or S8, respectively, and chlorine is described.


1973 ◽  
Vol 51 (3) ◽  
pp. 402-404 ◽  
Author(s):  
A. Bree ◽  
R. A. Kydd ◽  
V. V. B. Vilkos ◽  
R. S. Williams

A study of the polarized infrared and Raman spectra of acenaphthylene single crystals has been made. These results, together with Gordon and Yang's preliminary X-ray work, suggest that the molecules pack in some disordered arrangement in the solid at room temperature. Most of the A1 fundamentals were identified in the Raman solution spectrum from their low depolarization ratio, and a few tentative assignments of nontotally symmetric fundamentals were made.


1972 ◽  
Vol 26 (5) ◽  
pp. 540-542 ◽  
Author(s):  
G. R. Burns ◽  
D. G. McGavin

Infrared and Raman spectra have been measured for spiropentane-H8. Raman spectra for the liquid have enabled the b1 species ring twist to be assigned. Previous assignments of this mode were based on calorimetric data and on the assignment of a band in the infrared spectrum to a combination band involving the ring twist mode. Infrared spectra of low temperature crystalline films have provided sufficient information that, when taken with the Raman data and gas phase infrared spectra, we have assignments for all of the fundamental modes.


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