Exploring Intermediate Bonding Interactions in Sesquioxides (M2O3, M = In, Y, Al) From Experimental Charge Density Analysis

The bonding features of sesquioxides have been thoroughly investigated by precise experimental charge density distribution using the Maximum Entropy Method (MEM) and multipole models of charge density. The topology of the charge density is investigated and the atoms enacting different bonding characteristics and vibrations at different symmetries are well documented by studying (3,-1) bond critical points. The intermediate nature of interactions are visibly evident in the systems and are mapped. In the course of study, evidences of an increase in closed-shell interaction characteristics of bonding with the increase in the oxidation state of the metal cations in binary oxides are also witnessed. Thermal vibration parameters and charge density at the mid-bond regions, observed in the compound Y₂O₃, shows that its lattice is more rigid and has more covalent character than Al₂O₃ and In₂O₃. The charge integration studies explored the high ionic conductivity nature of In₂O₃.