Crystal structures of a natural and a Cs-exchanged clinoptilolite

Journal Article · Tue May 01 00:00:00 EDT 1990 · American Mineralogist

OSTI ID:137967

Smyth, J R; Spaid, A T ^[1]; Bish, D L ^[2]

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1. Univ. of Colorado, Boulder (USA)
2. Los Alamos National Laboratory, NM (USA)

The crystal structures of natural and Cs-exchanged silica-rich clinoptilolite have been refined in space group C2/m using single-crystal X-ray diffraction data (R = 0.062 and 0.083, respectively; all reflections). Chemical formulae of the two structures are Na{sub 1.3}K{sub 1.2}Ca{sub 1.55}Al{sub 6.2}Si{sub 29.8}O{sub 72}{center_dot}23H{sub 2}O and Cs{sub 3.8}Ca{sub 1.2}Al{sub 6.1}Si{sub 29.7}O{sub 72}{center_dot}19H{sub 2}O. Unit-cell dimensions of the two are virtually identical (a = 17.633 {angstrom}, b = 17.941 {angstrom}, c = 7.400 {angstrom}, and {beta} = 116.39{degree} for the natural sample, and a = 17.692 {angstrom}, b = 17.945 {angstrom}, c = 7.404 {angstrom}, and {beta} = 116.36{degree} for the Cs-exchanged sample). The positions of extra-framework cations in the natural sample are similar to those reported previously, except that there is no atom at the position ascribed to Mg, consistent with the low Mg content of the sample. Cs occupies split positions near high-symmetry special positions that are unrelated to the cation positions in the natural sample. All Cs positions have relatively long Cs-H{sub 2}O and Cs-O distances ranging from 3.0 to 3.5 {angstrom}. Clinoptilolite is a major component in tuffs at the Nevada Test Site, a large reservation in southern Nevada used for underground testing of nuclear weapons, and it may be used for future isolation of high-level radioactive wastes.

• OSTI ID: 137967
• Journal Information: American Mineralogist, Vol. 75, Issue 5-6; Other Information: PBD: May-Jun 1990
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
05 NUCLEAR FUELS
CLINOPTILOLITE
CRYSTAL STRUCTURE
ALUMINIUM OXIDES
CALCIUM OXIDES
CESIUM
CESIUM OXIDES
CHEMICAL COMPOSITION
DIMENSIONS
GEOCHEMISTRY
HIGH-LEVEL RADIOACTIVE WASTES
HYDRATES
ION EXCHANGE
NEVADA TEST SITE
POTASSIUM OXIDES
RADIOACTIVE WASTE DISPOSAL
SILICON OXIDES
SODIUM OXIDES
TUFF
X-RAY DIFFRACTION
ZEOLITES
Yucca Mountain Project