Mössbauer spectra of orthoericssonite in the temperature range 78–547 K reveal very low quadrupole splittings (QS=0.26–0.31 mm/s) for pentacoordinated Fe³⁺, which is shown to be a consequence of the size of the angle between equatorial bonds and the apical bond of this site. At temperatures above 298 K the Mössbauer centroid shift (CS) decreases linearly at −8.0 (±1.1) ·10⁻⁴mm·s⁻¹ ·deg⁻¹, which is in good agreement with the theoretical value of −7.3 ·10⁻⁴mm ·s⁻¹ ·deg⁻¹. In agreement with previous chemical analyses of the studied samples minor absorption doublets caused by the presence of ferrous iron were recorded in the spectra of a sample from the Hijikuzu mine, Japan. Mössbauer spectra indicate that ferrous iron substitutes for manganese randomly at all three types of octahedral sites found in the orthoericssonite structure.

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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 Po₂ and compositional ratio x in Mn_xFe_3−xO₄ (x=1 to 3). The concentration of metal vacancy was zero and a considerable amount of Fe²⁺ in the octahedral site, which was equal to Fe³⁺ in the tetrahedral site, appeared in case of appropriate values of equilibrium constants and small values of Po₂. The distribution results in a fairly good agreement with the reported Mössbauer spectroscopic data. In spite of constant metal ratio, the concentraion of Fe²⁺ is lessened with increasing Po₂ and metal vacancy in the tetrahedral site appeared considerably. These results suggest that the estimation of temperature and Po₂ for formation of natural specimen is possible from the observed values of cation distribution, if some thermodynamic values are known.

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