The prepared cubic spinels share the same reflections, which are only are slightly shifted according to the size of the unit cell (Figure ). The cell parameters obtained after Rietveld refinement are reported in Table , while the information provided about the spinel configuration has not been experimentally estimated, and solely refers to the configurations reported in the literature as the most stable ones for a composition. Spinel cobaltite are in general the most stable phase at room and low temperatures, which ensures stability during storage and enables low-temperature processing for their synthesis. Co 3O4, which is a normal spinel, has a broad range of stability in air, spanning from room temperature to about 900 °C, above which it turns into a monoxide. The addition of Mn to the framework makes MnCo2O4 an inverse spinel, meaning that Mn significantly alters the distribution of cations. This seems to influence also the size of the cell, with MnCo2O4 cell being relatively bigger than the one of the Co-only counterpart. As a result, it can be inferred that the M-O bonds would, in turn, be longer. MnCo2O4 behaves rather similarly to Co3O4 upon heating, with the cubic spinel phase stable up to about 1000 °C. The situation is different for NiCo2O4, which is also an inverse spinel. Differently from Mn, which is much more versatile in terms of oxidation states, Ni 2+ is the only available state for Ni, hence all Co in the solid would be Co 3+ as a result.