For the fully or highly reduced structures, triangular Pt3 motifs are prevalent and the structures are quite planar. As the particle becomes oxidized, it loses flatness in order to accommodate the new oxygen atoms while maintaining at least a mirror plane. This is prevalent for Pt6Ox stoichiometries in low oxidation states but it loses importance for higher oxidation states. In higher oxidation states the size of the particle forces it to bridge positions between two same Pt atoms, giving rise to the formation of planar PtO4 motifs for highly oxidized states. Quasi-molecular forms of O pairs also appear in stable structures (see e.g. Pt6O7), although such motifs are less frequent.