Spectroscopic characterization of alkali-metal exchanged natrolites

Yongjae Lee, Dan Liu, Zhenxian Liu, Donghoon Seoung, Yongmoon Lee

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Synchrotron infrared (IR) and micro-Raman spectroscopic studies have been performed on zeolite natrolites as a function of the non-framework composition at ambient conditions. This establishes the spectroscopic characterization of the ion-exchanged natrolites in the alkali-metal series both in the as-prepared hydrated (M-NAT-hyd, M = Li, Na, K, Rb, and Cs) and some stable dehydrated forms (M-NAT-deh, M = Rb and Cs). The former series exhibits non-framework cation-size dependent opening of the helical channels to span ca. 21° range in terms of the chain rotation angle, ? (or ca. 45° range in terms of the chain bridging angle, T-O2-T). For these hydrated phases, both IR and Raman spectra reveal that the degree of the red-shifts in the frequencies of the helical 8-ring channel as well as the 4-ring unit is proportional to the ionic radius of the non-framework cations. Linear fits to the data show negative slopes of -55.7 from Raman and -18.3 from IR in the 8-ring frequencies and ionic radius relationship. The spectroscopic data are also used to identify the modes of the dehydration-induced "collapse" of the helical 8-ring channels as observed in the stable anhydrous Rb-NAT-deh and Cs-NAT-deh. In addition, we demonstrate that the spectroscopic data in the hydrated series can be used to distinguish different water arrangements along the helical channels based on the frequency shifts in the H-O-H bending band and the changes in the O-H stretching vibration modes.

Original languageEnglish
Pages (from-to)419-424
Number of pages6
JournalAmerican Mineralogist
Volume97
Issue number2-3
DOIs
Publication statusPublished - 2012 Feb 1

Fingerprint

Alkali Metals
alkali metal
alkali metals
rings
Infrared radiation
Cations
cation
Zeolites
cations
radii
Synchrotrons
Dehydration
dehydration
zeolite
red shift
frequency shift
Stretching
Raman scattering
vibration mode
vibration

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Geochemistry and Petrology

Cite this

Lee, Yongjae ; Liu, Dan ; Liu, Zhenxian ; Seoung, Donghoon ; Lee, Yongmoon. / Spectroscopic characterization of alkali-metal exchanged natrolites. In: American Mineralogist. 2012 ; Vol. 97, No. 2-3. pp. 419-424.
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Spectroscopic characterization of alkali-metal exchanged natrolites. / Lee, Yongjae; Liu, Dan; Liu, Zhenxian; Seoung, Donghoon; Lee, Yongmoon.

In: American Mineralogist, Vol. 97, No. 2-3, 01.02.2012, p. 419-424.

Research output: Contribution to journalArticle

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AU - Lee, Yongjae

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