The volume of solvent promoted a different incorporation of Mn 2+ in the spinel structure (Figure in the S.I.). When the same Fe(acac)3/Mn(acac)2 ratio was used, the amount of Mn 2+ incorporated in the spinel structure was always higher in the serie produced using a smaller volume of solvent (B series) than in A Series (Table ). One hypothesis is that the use of a smaller amount of solvent facilitates higher and more uniform temperatures throughout the mixture, improving the decomposition of Mn(acac)2 precursor and thereby reducing the critical gap between the decomposition of metallic precursors before the saturation limit for particle nucleation .