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Crystal chemistry of synthetic hercynite (FeAl (sub 2) O (sub 4) ) from XRD structural refinements and Moessbauer spectroscopy

Lena Larsson, Hugh St. C. O'Neill and Hans Annersten
Crystal chemistry of synthetic hercynite (FeAl (sub 2) O (sub 4) ) from XRD structural refinements and Moessbauer spectroscopy
European Journal of Mineralogy (February 1994) 6 (1): 39-51

Abstract

Both the crystal chemistry and thermal behaviour of synthetic hercynite produced hydrothermally and by sintering oxides at high T were studied, the samples being annealed at different T under controlled O (sub 2) atmospheres in a gas mixture furnace using CO (sub 2) /CO gas mixtures, and subsequent quenching. The inversion parameter, x, increases from 0.101 at 500 degrees C to 0.187 at 900 degrees C as determined by XRD, or from 0.162 to 0.19 respectively, as determined by Mossbauer spectroscopy. The increase in x is accompanied by a similar smooth decrease of the oxygen positional parameter, u. The thermal behaviour is anomalous compared to previously studied simple oxide spinels, perhaps due to the extreme sensitivity of the defect chemistry of hercynite to variations in oxidation state, leading to the formation of ferric iron and vacancies in solid solution at elevated T.


ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 6
Serial Issue: 1
Title: Crystal chemistry of synthetic hercynite (FeAl (sub 2) O (sub 4) ) from XRD structural refinements and Moessbauer spectroscopy
Affiliation: Uppsala University, Institute of Earth Sciences, Uppsala, Sweden
Pages: 39-51
Published: 199402
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 25
Accession Number: 1994-025434
Categories: Mineralogy of non-silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: 4 tables
Secondary Affiliation: Universitaet Bayreuth, DEU, Federal Republic of Germany
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United KingdomTwickenhamUKUnited Kingdom
Update Code: 199412
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