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GEOREF RECORD

On the H-form of natrolite

Anna Yu. Likhacheva, Sergey A. Veniaminov, Eveniy A. Paukshtis and Igor A. Belitsky
On the H-form of natrolite
European Journal of Mineralogy (June 2006) 18 (3): 345-350

Abstract

The thermal decomposition of NH (sub 4) -exchanged natrolite (a precursor of the H-form) was studied by GC, IR spectroscopy and XRD. Throughout the decomposition, the de-ammoniation is followed immediately by dehydroxylation, providing evidence for the instability of the H-natrolite formed after removal of NH (sub 3) , and leads to a negligibly small concentration of the OH groups. The natrolite structure cannot persist after removal of NH (sub 3) . In the final decomposition step, the adsorption of NH (sub 3) onto Lewis centres accumulated in the amorphosed framework hinders the de-ammoniation. This appears to be a major factor influencing the observed increase in the activation energy for NH (sub 3) desorption from 117 (+ or - 13) kJ/mol in the initial step to 270 (+ or - 20) kJ/mol. Smooth vacuum degassing of NH (sub 4) -natrolite at 550 K leads to partial de-ammoniation, rather than the formation of H-natrolite.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 18
Serial Issue: 3
Title: On the H-form of natrolite
Affiliation: Institute of Mineralogy and Petrography, Novosibirsk, Russian Federation
Pages: 345-350
Published: 200606
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 19
Accession Number: 2006-061006
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus.
Secondary Affiliation: Boreskov Institute of Catalysis, RUS, Russian Federation
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 200634
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