With direct evidence from TEM and XRD analysis showing the evolution of the m = 6 phase as the concentration of Ti decreases and the levels of Fe and Mn increase, we next explore how the structural rearrangement of the Aurivillius phase to higher m values accommodates the increased Mn content. Theoretical scenarios are outlined in Table . For example, consider the chemical composition of the m = 5 Bi6Ti2.30Fe2.00Mn0.70O18 phase. When rearranged into the m = 6 structure, it assumes the composition Bi7Ti2.76Fe2.40Mn0.84O21. In Table , for the m = 5 phase (composition Bi6Ti2.30Fe2.00Mn0.70O18), the average oxidation state of Mn is calculated to be +4.00, assuming oxidation states of +4 for Ti and +3 for Fe. When the same ratio of Ti, Fe and Mn cations is applied to the m = 6 structure (composition Bi7Ti2.76Fe2.40Mn0.84O21), the average oxidation state of Mn is calculated to be +3.29. The value falls within the range reported for stable Aurivillius phase compositions by Zurbuchen et al. (Mn 3.2+ ) and McCabe and Greaves 21 (Mn 3.4+ ). It is important to note that while the relative proportions of the B-site atoms remain the same for both arrangements (as shown in Table ), the proportion of Mn⁴⁺ required to achieve charge-balanced stoichiometry is significantly lower for the m = 6 phase (4.06% Mn⁴⁺) compared to the m = 5 phase (14.00% Mn⁴⁺). This explains how the formation of the higher m = 6 Aurivillius phase allows for the accommodation of a higher concentration of magnetic cations while maintaining balanced stoichiometry.