Reconstructive and displacive transformations of tectosilicates

  • V. Dondur
  • S. Markovic
  • R. Dimitrijevic
  • S. Macura
  • D. Arandjelovic
Article

DOI: 10.1023/A:1023969130688

Cite this article as:
Dondur, V., Markovic, S., Dimitrijevic, R. et al. Journal of Thermal Analysis and Calorimetry (2003) 72: 373. doi:10.1023/A:1023969130688

Abstract

By using the thermally induced phase transformation initial zeolites were converted into pure carnegieite, stuffed derivative of cristobalite. The polymorphs obtained from Na-LTA are stoichiometric (NaAlSiO4), since those obtained from Na-FAU zeolite are non-stoichiometric (Na1-xAl1-xSi1+xO4). Stoichiometric carnegieite have cubic structure, while non-stoichiometric carnegieite crystallized in cubic and orthorhombic forms. 29Si MAS NMR spectra show a very large but expecting difference between stoichiometric and non-stoichiometric carnegieite. The spectrum of stoichiometric carnegieite has only one peak Si(4Al), while the spectrum of non-stoichiometric carnegieite consist few superimposed peaks assigned to Si(4Al), Si(3Al), Si(2Al), Si(1Al) and Si(0Al). DTA study indicates the occurrence of displacive phase transition of all synthesized carnegieite. The transition temperature is depending on silicon aluminum order: Tm=690°C for stoichiometric, Tm=565 and 660°C for non-stoichiometric, low-temperature and high-temperature carnegieite, respectively.

DTA carnegieite FAU zeolite LTA zeolite 

Copyright information

© Kluwer Academic Publishers/Akadémiai Kiadó 2003

Authors and Affiliations

  • V. Dondur
    • 1
  • S. Markovic
    • 1
  • R. Dimitrijevic
    • 2
  • S. Macura
    • 3
  • D. Arandjelovic
    • 1
  1. 1.Faculty of Physical ChemistryBelgradeYugoslavia
  2. 2.Faculty of Mining and GeologyDepartment of CrystallographyBelgradeYugoslavia
  3. 3.Department of Biochemistry, Mayo FoundationRochesterUSA

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