Short communications Analytic calculation of cation distribution equilibria in the cubic phase of jacobsite-hausmannite system

摘要

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_2 and compositional ratio x in Mn_xFe_(3-x)O_4 (x = 1 to 3). The concentration of metal vacancy was zero and a considerable amount of Fe~(2+) in the octahedral site, which was equal to Fe~(3+) in the tetrahedral site, appeared in case of appropriate values of equilibrium constants and small values of Po_2. The distribution results in a fairly good agreement with the reported Moessbauer spectroscopic data. In spite of constant metal ratio, the concentraion of Fe~(2+) is lessened with increasing Po_2 and metal vacancy in the tetrahedral site appeared considerably. These results suggest that the estimation of temperature and Po_2 for formation of natural specimen is possible from the observed values of cation distribution, if some thermodynamic values are known.