Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Clays and Clay Minerals Don't get GSW? Talk to your librarian.
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Clays and Clay Minerals; August 2005; v. 53; no. 4; p. 380-388; DOI: 10.1346/CCMN.2005.0530406
© 2005 Clay Minerals Society
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bertoldi, C.
Right arrow Articles by Groger, W.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

THE HEAT CAPACITY OF THE SERPENTINE SUBGROUP MINERAL BERTHIERINE (Fe2.5Al0.5)[Si1.5Al0.5O5](OH)4

Christian Bertoldi1,*, Edgar Dachs1, Lado Cemic2, Thomas Theye3, Richard Wirth4 and Werner Groger5

1 Abteilung Mineralogie und Materialwissenschaften, Fachbereich Geographie, Geologie und Mineralogie, Paris Lodron Universität Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria
2 Institut für Geowissenschaften, Christian Albrechts Universität zu Kiel, Ludewig-Meyn-Strasse 10, 24118 Kiel, Germany
3 Institut fär Mineralogie und Kristallchemie, Universität Stuttgart, Azenbergstrasse 18, 70174 Stuttgart, Germany
4 GeoForschungsZentrum Potsdam, Telegraphenberg, 14473 Potsdam, Germany
5 Forschungsinstitut für Elektronenmikroskopie und Feinstrukturforschung, Technische Universität Graz, Steyrergasse 17, 8010 Graz, Austria

* E-mail address of corresponding author: christian.bertoldi{at}sbg.ac.at

The serpentine subgroup mineral berthierine was synthesized as a metastable precursor of the chlorite group mineral chamosite in cold seal pressure vessels at 575°C, 0.5 GPa and fO2-conditions of the NNO buffer from a glass of almandine bulk composition. The run products were investigated with X-ray powder diffraction (XRD), Mössbauer spectroscopy and electron microprobe analysis. One run product was also investigated by high-resolution transmission electron microscopy (HRTEM) and its heat capacity measured by heat pulse calorimetry and by differential scanning calorimetry in the temperature range 5–323 K. The XRD and HRTEM investigations clearly showed that the periodicity along the c axis of this sample is 7 Å demonstrating that the serpentine subgroup mineral berthierine of composition (Fe1.832+ Fe0.333+ Al0.67)[Si1.33Al0.67O5](OH)4 has formed in the synthesis experiments.

Integration of our heat capacity data, corrected to the composition (Fe2.5Al0.5)[Si1.5Al0.5O5](OH)4 for end-member berthierine, yields a standard entropy of 284.1 ± 0.3 J mol–1 K–1. The Cp polynomial Cp = 610.72 – 5140.0 x T–0.5 – 5.88486106 T–2 + 9.5444 x 108 T–3 is recommended for thermodynamic calculations above 298 K involving berthierine.

Key Words: Berthierine • Differential Scanning Calorimetry • Heat Capacity • Heat-pulse Calorimetry • Serpentine Subgroup Minerals • Standard Entropy






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2008 by Clay Minerals Society