Polymorphism of molecules and complex ions in oxygen compounds of silicon and phosphorus. Communication 4. Phase transitions and conformations of the octamethylcyclotetrasiloxane molecule [OSi(CH3)2]4

  • A. N. Lazarev
  • T. F. Tenisheva
Physical Chemistry
  • 36 Downloads

Conclusions

  1. 1.

    The phase transition in crystalline octamethylcyclotetrasiloxane is due to transition of the molecules from Ci to S4 symmetry. During melting, a further change in the structure of the molecule occurs; in the liquid phase it apparently possesses C4 symmetry, which is also preserved in the gas phase.

     
  2. 2.

    The transformations of the molecule [OSi(CH3)2]4 consist of a change in the conformation of ring and do not lead to any significant change in the bond lengths and valence angles in the ring. A vital role in the mechanism of the molecular rearrangement is played by the lability of the SiOSi angle-thermal excitation of the nonplanar deformational vibrations of the siloxane ring.

     

Keywords

Oxygen Silicon Phosphorus Phase Transition Liquid Phase 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Literature cited

  1. 1.
    A. N. Lazarev, Izv. AN SSSR. Ser. Khim.,1964, 235.Google Scholar
  2. 2.
    A. N. Lazarev and T. F. Tenisheva, Izv. AN SSSR. Ser. Khim.,1964, 242.Google Scholar
  3. 3.
    A. N. Lazarev and T. F. Tenisheva, Izv. AN SSSR. Ser. Khim.,1964, 403.Google Scholar
  4. 4.
    E. G. Rochow and H. G. Clair, J. Inorgan. Nucl. Chem.,1, 92 (1955).Google Scholar
  5. 5.
    J. D. Hoffman, J. Amer. Chem. Soc.75, 6361 (1935).Google Scholar
  6. 6.
    H. Steinfink, B. Post and I. Fankuchen, Acta crystallogr,8, 420 (1955).Google Scholar
  7. 7.
    H. Kriegsmann, Z. anorgan. und allgem. chem.,298, 232 (1959).Google Scholar
  8. 8.
    G. Herzberg, Vibrational and Rotational Spectra of Polyatomic Molecules [Russian translation], Foreign Literature Press, Moscow (1949).Google Scholar
  9. 9.
    A. S. Mayants, Theory and Calculation of Molecular Vibrations [in Russian], Academy of Sciences USSR Press, Moscow (1960).Google Scholar
  10. 10.
    J. R. Aronson, R. C. Lord and D. W. Robinson, J. Chem. Phys.,33, 1004 (1960).Google Scholar
  11. 11.
    W. R. Thorson and I. Nadagawa, J. Chem. Phys.33, 994 (1960).Google Scholar

Copyright information

© Consultants Bureau Enterprises, Inc. 1965

Authors and Affiliations

  • A. N. Lazarev
    • 1
  • T. F. Tenisheva
    • 1
  1. 1.I. V. Grebenshchikov Institute of Silicate ChemistryAcademy of Sciences USSRUSSR

Personalised recommendations