Pressure-induced symmetry changes in body-centred cubic zeolites

Research output: Contribution to journalArticle

Authors

  • Mero Lee U. Cornelius
  • Zöe L. Jones1
  • I. E. Collings
  • Stephen A. Wells
  • Paul R. Raithby
  • Asel Sartbaeva

Colleges, School and Institutes

External organisations

  • University of Bath
  • University of the Western Cape
  • European Synchrotron Radiation Facility

Abstract

Previous work has shown a strong correlation between zeolite framework flexibility and the nature of structural symmetry and phase transitions. However, there is little experimental data regarding this relationship, in addition to how flexibility can be connected to the synthesis of these open-framework materials. This is of interest for the synthesis of novel zeolites, which require organic additives to permutate the resulting geometry and symmetry of the framework. Here, we have used high-pressure powder X-ray diffraction to study the three zeolites: Na-X, RHO and ZK-5, which can all be prepared using 18-crown-6 ether as an organic additive. We observe significant differences in how the occluded 18-crown-6 ether influences the framework flexibility-this being dependent on the geometry of the framework. We use these differences as an indicator to define the role of 18-crown-6 ether during zeolite crystallization. Furthermore, in conjunction with previous work, we predict that pressureinduced symmetry transitions are intrinsic to body-centred cubic zeolites. The high symmetry yields fewer degrees of freedom, meaning it is energetically favourable to lower the symmetry to facilitate further compression.

Details

Original languageEnglish
Article number182158
JournalRoyal Society Open Science
Volume6
Issue number7
Publication statusPublished - 24 Jul 2019

Keywords

  • Cubic, High pressure, Phase transition, Symmetry, X-ray diffraction, Zeolite

ASJC Scopus subject areas