Looking at the magnetic moments of the minority subset shows deviations from the expected d 5 Mn 2+ and Fe 3+ configurations. For each structure in the subset there is a coupling between an octahedral Mn and tetrahedral Fe resulting in a lowering of the overall magnetic moment of both the Mn and Fe. For all structures these sites are direct neighbours as shown in Figure . The average magnitude of the magnetic moment for octahedral and tetrahedral Fe sites is 4.2 µB in the non-coupled sites. The average magnetic moment decreases significantly to 3.7 µB in the coupled subset. For Mn, the average magnitude of magnetic moments are 4.6 µB for octahedral and tetrahedral sites of the non-coupled structures. The average magnetic moment is again decreased for the coupled subset to 3.9 µB. The origin of this can be attributed to an oxidation of Mn 2+ to Mn 3+ and a reduction of Fe 3+ to Fe 2+ .