The stability of cations occupying surface sites also depends on their interaction with the surface ligand and/or the solvent . Figure shows the FT-IR spectra of the selected MNPs with the lowest (xEmpiric = 0.07) and the highest Mn 2+ content (xEmpiric = 1.10) after PMAO coating. In region I, the signals of ν(C-H) stretching mode belonging to the OA anchored to the surface of MNPs dominate, being more intense for the sample with the highest percentage of OA (xEmpiric = 0.07), as also confirmed by TGA.