High-pressure behavior and crystal-fluid interaction under extreme conditions in paulingite [PAU-topology]

Author(s)

Giacomo Diego Gatta, Katharina Sarah Scheidl, Thomas Pippinger, Roman Skala, Yongjae Lee, Ronald Miletich-Pawliczek

Abstract

The compressional behavior and the P-induced crystal-fluid interaction of a natural paulingite-K have been explored on the basis of in-situ single-crystal and powder X-ray diffraction, and in-situ single-crystal Raman spectroscopy with a diamond anvil cell and a series of diverse pressure-transmitting fluids (i.e., silicone-oil, methanol:ethanol = 4:1, methanol:ethanol:water = 16:3:1). No evidence of any phase transition was observed within the P-range investigated, independent on the used P-fluids. The compressional behavior of paulingite is significantly different in response to the different nature of the P-fluids. A drastically lower compressibility is observed when the zeolite is compressed in methanol:ethanol or, even more noticeably, in methanol:ethanol:water mix. We ascribe this phenomenon to the different crystal-fluid interaction at high pressure: (1) silicone-oil is a "non-penetrating" P-medium, because of its polymeric nature, whereas (2) methanol-ethanol and water are "penetrating" P-fluids. The P-induced penetration processes appear to be completely reversible on the basis of the X-ray diffraction data alone. The Raman spectra collected after the high-pressure experiments show, unambiguously, that a residual fraction of methanol (and/or ethanol and probably even extra H

₂O) still resides in the zeolitic sub-nanocavities; such molecules are spontaneously released after a few days at atmospheric pressure. The actual compressibility of paulingite-K is that obtained by the compression experiment in silicone-oil, with an isothermal bulk modulus K

₀ = β

₀

^-1 = 18.0(1.1) GPa. Paulingite appears to be one of the softest zeolite ever found.

Organisation(s)

Department of Mineralogy and Crystallography

External organisation(s)

Università degli Studi di Milano-Bicocca, Charles University Prague, Yonsei University

Journal

Microporous and Mesoporous Materials

Volume

206

Pages

34-41

No. of pages

8

ISSN

1387-1811

DOI

https://doi.org/10.1016/j.micromeso.2014.11.031

Publication date

12-2014

Peer reviewed

Yes

Austrian Fields of Science 2012

105116 Mineralogy, 104011 Materials chemistry, 105113 Crystallography

Keywords

ASJC Scopus subject areas

Condensed Matter Physics, Mechanics of Materials, General Chemistry, General Materials Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/498d4af6-f0c8-474a-aa87-2941fa074dbb