Anisotropic elastic behaviour and structural evolution of zeolite phillipsite at high pressure: A synchrotron powder diffraction study

G. Diego Gatta, Yongjae Lee

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25 Citations (Scopus)


The high-pressure (HP) elastic behaviour and the P-induced structural evolution of a natural zeolite phillipsite, K2CanNa2-nAl4+nSi12-nO32 · 12H2O (with n ≤ 2) [a = 9.9291(3), b = 14.2621(6), c = 8.6920(5) Å, β = 124.592(3)°, space group P21/m], has been investigated by in situ synchrotron X-ray powder diffraction up to 3.64 GPa using a diamond anvil cell and a nominally penetrating hydrous P-transmitting medium. No phase transition has been observed within the P-range investigated. Axial and volume bulk moduli have been calculated using a truncated second-order Birch-Murnaghan Equation-of-State. The refined elastic parameters are: V0 = 1013.3(1) Å3, K0 = 67(2) GPa [β = 0.0149(5) GPa-1] for the unit-cell volume; a0 = 9.9290(7) Å, K(a) = 69(2) GPa [β(a) = 0.0048(2) GPa-1] for the a-axis; b0 = 14.262(2) Å, K(b) = 49(2) GPa [β(b) = 0.0068(3) GPa-1] for the b-axis and c0 = 8.691(1) Å, K(c) = 111(3) GPa [β(c) = 0.00300(8) GPa-1] for the c-axis, with K(a):K(b):K(c) = 1.41:1:2.26. The magnitude of the principal unit-strain coefficients, between 0.0001 GPa and 3.64 GPa, were calculated. The unit-strain ellipsoid is oriented with ε1∥b, ε2 and ε3 lying on the (0 1 0) plane with ε3∠a = 115.1(3)° and {divides}ε1{divides} > {divides}ε2{divides} > {divides}ε3{divides}. The structural refinements performed at high-P allow to explain the reasons of the elastic anisotropy. The cooperative rotation of the tetrahedra increase the ellipticity of the channel systems, maintaining the original elliptical configuration (without any "inversion" in ellipticity).

Original languageEnglish
Pages (from-to)239-250
Number of pages12
JournalMicroporous and Mesoporous Materials
Issue number3
Publication statusPublished - 2007 Oct 1

Bibliographical note

Funding Information:
This work was supported (in part) by Yonsei University Research Fund of 2005-1-0475. Research carried out (in part) at the National Synchrotron Light Source, Brookhaven National Laboratory, is supported by the US Department of Energy, Division of Materials Sciences and Division of Chemical Sciences. Two anonymous reviewers are thanked for their useful suggestions.

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials


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