Experimentally, there are various reports of the presence of Mn 3+ and Fe 2+ in the Mn-Fe-Zn-O spinel phase field. Harrison and coworkers determine for a sample of MnFe 2 O 4 that approximately 7 % of Fe is in the Fe 2+ state and 17 % of Mn is in the Mn 3+ state. Ji and coworkers 56 find a Zn-doped MnFe 2 O 4 with a slight excess of Fe resulting in approximately 3 % of Fe in the Fe 2+ state with Ti 4+ doping increasing the amount of Fe 2+ up to 6 %. Bonsdorf and coworkers 57 find a temperature dependence for the Mn 2+ /Mn 3+ ratio where high temperature processing forms Mn 2+ exclusively. Their work however finds no existence of Fe 2+ using Mössbauer spectroscopy. Carta and coworkers argue that in a pure sample of MnFe 2 O 4 , a highly inverted structure ( 70% inversion) is attributed to partial oxidation of Mn 2+ to Mn 3+ . Antic and coworkers on the other hand show cation deficit Zn-Mn ferrites where they observe no Mn 3+ but claim the presence of Mn 4+ . They also find Fe 2+ in small quantities. These experimental reports suggest that the presence of Mn 3+ and Fe 2+ in Zn-Mn ferrite spinels is certainly possible but that this is strongly dependent on synthesis methods and conditions. It is noted that the orbital occupancies and magnetic moments calculated by the DFT+U approach used in our study will depend on the value of U used. Nevertheless, our results are consistent with experimental reports of the presence of Fe 2+ and Mn 3+ in members of this solid solution.