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A neutron powder diffraction study of partially dehydrated fluorapophyllite, KCa (sub 4) Si (sub 8) O (sub 20) F.6.9H (sub 2) O

Kenny Stahl
A neutron powder diffraction study of partially dehydrated fluorapophyllite, KCa (sub 4) Si (sub 8) O (sub 20) F.6.9H (sub 2) O
European Journal of Mineralogy (October 1993) 5 (5): 845-849

Abstract

Natural fluorapophyllite (8 H (sub 2) O) from Poona, India, was dehydrated at 473 K to an average of 4 H (sub 2) O. The dehydration is a two-step process, the first step leading to 7 H (sub 2) O as one H (sub 2) O is expelled with the remaining H (sub 2) O of a mirror- related pair assuming a new position in the mirror plane. In the second step, continued dehydration destabilizes the K and Ca coordinations which connect the silicate layers and a non- diffracting amorphous phase is formed. The sample is then a mixture of the crystalline form with 7 H (sub 2) O and the amorphous form. Partially dehydrated fluorapophyllite (6.9 H (sub 2) O) is tetragonal, space group P4/mnc, Z = 2; a 8.9639, c 15.754 Angstrom at 295 K.


ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 5
Serial Issue: 5
Title: A neutron powder diffraction study of partially dehydrated fluorapophyllite, KCa (sub 4) Si (sub 8) O (sub 20) F.6.9H (sub 2) O
Author(s): Stahl, Kenny
Affiliation: University of Lund, Inorganic Chemistry 2, Lund, Sweden
Pages: 845-849
Published: 199310
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 8
Accession Number: 1993-041709
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 1993
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