The Reactivity of the Metal Oxide‐Water and Mineral‐Water Interfaces – An Inorganic/Coordination Viewpoint

The reactivity of the metal oxide‐water interface and that of the mineral‐water interface can be understood from the viewpoint of coordination chemistry, comparing the reactivity of a metal ion belonging to the surface of a solid with the reactivity of the same metal ion dissolved in an aqueous solution. Ligand substitution reactions are key reactions for metal complexes in solution and metal complexes at the surface. At the surface, these processes lead to the formation of adsorbed species, which can be identified by different surface spectroscopic techniques. Surface reactions, such as proton adsorption‐desorption and anion and cation adsorption‐desorption, are easily understood in this context. With the aid of kinetic measurements performed by ATR‐FTIR, it is shown that adsorption‐desorption reactions should take place through dissociative (D), associative (A), or interchange mechanisms (Id, Ia), as they also occur in solution. The surfaces of metal oxides and most minerals are formed by metal complexes reacting as complexes in solution. Protonation‐deprotonation, ligand substitution, and condensation reactions can take place at these surfaces when they are in contact with an aqueous solution, leading to chemisorption processes of paramount importance in environmental chemistry.