Analytic calculation of cation distribution equilibria in the cubic phase of jacobsite-hausmannite system
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Cation and cation vacancy distribution equilibria in the cubic phase of jacobsite-hausmannite solid solution system have been calculated by a defect-chemical approach as a function of some equilibrium constants, partial pressure of oxygen Po<SUB>2</SUB> and compositional ratio x in Mn<SUB>x</SUB>Fe<SUB>3−x</SUB>O<SUB>4</SUB> (x=1 to 3). The concentration of metal vacancy was zero and a considerable amount of Fe<SUP>2+</SUP> in the octahedral site, which was equal to Fe<SUP>3+</SUP> in the tetrahedral site, appeared in case of appropriate values of equilibrium constants and small values of Po<SUB>2</SUB>. The distribution results in a fairly good agreement with the reported Mössbauer spectroscopic data. In spite of constant metal ratio, the concentraion of Fe<SUP>2+</SUP> is lessened with increasing Po<SUB>2</SUB> and metal vacancy in the tetrahedral site appeared considerably. These results suggest that the estimation of temperature and Po<SUB>2</SUB> for formation of natural specimen is possible from the observed values of cation distribution, if some thermodynamic values are known.
- Mineralogical Journal
Mineralogical Journal 17(8), 372-377, 1995-10-01
Japan Association of Mineralogical Sciences