Cation distribution in Cr-spinels from the Sittampundi layered complex and their intracrystalline thermodynamics

High aluminium chromites occur as bands within anorthosite layered complex of Sittampundi (Tamil Nadu). Cation distribution of two chromite samples is determined by combined electron probe microanalysis and Mössbauer spectroscopy. In the deconvolution of the Mössbauer spectra, the suitability of the...

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Bibliographic Details
Published in:Current science (Bangalore) 2006-02, Vol.90 (3), p.435-439
Main Authors: Mitra, Sachinath, Bidyananda, Maibam, Samanta, Asok Kumar
Format: Article
Language:English
Subjects:
Chromites
Enthalpy
Entropy
Minerals
Oxygen
RESEARCH COMMUNICATIONS
Room temperature
Solid solutions
Spinel
Thermodynamic equilibrium
Thermodynamics
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Summary:High aluminium chromites occur as bands within anorthosite layered complex of Sittampundi (Tamil Nadu). Cation distribution of two chromite samples is determined by combined electron probe microanalysis and Mössbauer spectroscopy. In the deconvolution of the Mössbauer spectra, the suitability of the best model of spectral fitting has been established with the observation that both Fe²⁺ and Fe³⁺ ions occur at tetrahedral (A) and octahedral (B) sites and Fe³⁺/ΣFe found to be ranging between 0.45 and 0.48. Oxygen fugacity (fO₂) has been determined to be about 10−7.3. Thermodynamic parameters have been determined for the studied chromites using standard models.
ISSN:0011-3891