Defect Structure and Transport Properties of Manganese Oxides: (II) The Nonstoichiometry of Hausmannite (Mn₃δO₄)

The deviation from stoichiometry δ in hausmannite (Mn 3  δ O 4 ) has been thermogravimetrically studied as a function of oxygen activity between 1000 and 1130°C for the low temperature phase (α‐Mn 3  δ O 4 ) and between 1200 and 1350°C for the high temperature phase (ß‐Mn 3  δ O 4 ). A cation deficit is observed at high oxygen activities and a cation excess at low oxygen activities. In the temperature range investigated, it is concluded that the dominant defect species in both phases are cation vacancies at high oxygen activities and manganese interstitials at low oxygen activities. In addition, based on the present nonstoichiometry data, the phase diagram of the maganese‐oxygen