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Enthalpies of formation of pyrrhotite Fe (sub 1-0.125x) S (0< or =x< or =1) solid solutions


Binary iron sulfides are of major interest and importance in environmental, geological, and planetary science. Oxidative high-temperature oxide melt drop-solution calorimetry in molten sodium molybdate (3Na (sub 2) O.4MoO (sub 3) ) solvent at 975 K was applied to determine the energetics of formation of the binary iron monosulfide solid solution (pyrrhotite) (Fe (sub 1-0.125x) S, 0< or =x< or =1). The enthalpies of formation from elements are consistent with earlier data in the literature, available for a few compositions. Within the experimental errors, the enthalpies of formation of the solid solution from the end-members Fe (sub 0.875) S and FeS (Delta H (sub mix) , kJ/mol) at 25 degrees C equal to zero. Under the assumption of random distribution of Fe vacancies, the Gibbs free energies of mixing of Fe (sub 1-0.125x) S (0< or =x< or =1) are estimated. Our data support the two-sublattice model proposed by Waldner and Pelton (2005).

ISSN: 0003-004X
EISSN: 1945-3027
Serial Title: American Mineralogist
Serial Volume: 95
Serial Issue: 5-6
Title: Enthalpies of formation of pyrrhotite Fe (sub 1-0.125x) S (0< or =x< or =1) solid solutions
Affiliation: University of California at Davis, Peter A. Rock Thermochemistry Laboratory, Davis, CA, United States
Pages: 717-723
Published: 201005
Text Language: English
Publisher: Mineralogical Society of America, Washington, DC, United States
References: 44
Accession Number: 2010-050150
Categories: Mineralogy of non-silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 7 tables
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, Mineralogical Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201027
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