Skip to Main Content
GEOREF RECORD

Dehydroxylation of Fe (super 3+) , Mg-rich dioctahedral micas; (I) Structural transformation

F. Muller, V. A. Drits, A. Plancon and G. Besson
Dehydroxylation of Fe (super 3+) , Mg-rich dioctahedral micas; (I) Structural transformation
Clay Minerals (June 2000) 35 (3): 491-504

Abstract

Celadonite and glauconite samples heated at different temperatures were studied by X-ray and electron diffraction. For dioctahedral micas the in-plane component of the translation between layers (ccosbeta /a), which is strongly dependent on the position of the vacant octahedral site, significantly decreases at temperatures greater than the temperature of maximum dehydroxylation. The simulation of XRD patterns from different structural models reveals the actual crystal structure of dehydroxylated samples as well as the dynamics of the structural transformations. In the non-heated state the samples consist of tv (trans-vacant) 2:1 layers. During dehydroxylation, cations migrate from cis- into trans-octahedra and have 5-fold coordination. In the averaged unit-cell the "residual" anions formed after the dehydroxylation reaction occupy the former OH sites with probability equal to 0.5. The migration of octahedral cations is accompanied by the transformation of the C-centred layer unit-cells into primitive ones. In contrast to Fe, Al and Mg cations have a greater ability to migrate.


ISSN: 0009-8558
EISSN: 1471-8030
Coden: CLMIAF
Serial Title: Clay Minerals
Serial Volume: 35
Serial Issue: 3
Title: Dehydroxylation of Fe (super 3+) , Mg-rich dioctahedral micas; (I) Structural transformation
Affiliation: University of Orleans, Orleans, France
Pages: 491-504
Published: 200006
Text Language: English
Publisher: Mineralogical Society, London, United Kingdom
References: 23
Accession Number: 2001-064931
Categories: Mineralogy of silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables
Secondary Affiliation: Russian Academy of Sciences, RUS, Russian Federation
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 200120
Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal