A chemical approach to understanding oxide surfaces

Chemical bonding has often been ignored in favor of physics based energetic considerations in attempts to understand the structure, stability, and reactivity of oxide surfaces. Herein, we analyze the chemical bonding in published structures of the SrTiO3, MgO, and NiO surfaces using bond valence sum (BVS) analysis. These simple chemical bonding theories compare favorably with far more complex quantum mechanical calculations in assessing surface structure stability. Further, the coordination and bonding of surface structures explains the observed stability in a readily comprehensible manner. Finally, we demonstrate how simple chemical bonding models accurately predict the adsorption of foreign species onto surfaces, and how such models can be used to predict changes in surface structures. ► We study chemical bonding at oxide surfaces. ► Bond valence sums agree with quantum mechanical calculations for surface structures. ► Coordination and bonding of surface atoms explains observed stability. ► Chemical bonding predicts adsorption and reactivity on surfaces. ► Chemical bonding predicts structural evolution of surfaces.