MOLECULAR-ORBITAL STUDY ON THE MECHANISM OF OXIDATION OF A BERYLLIUM ATOM IN ACIDIC SOLUTION

To elucidate the mechanism of metal hydrolysis in acidic solution, we have studied the reaction of a beryllium atom in acidic aqueous solution with ab initio molecular orbital theory. The oxidation process from Be0 to Be11 via Be1 can be regarded as the successive reaction between a Be atom and H3O+ ions, assisted by the surrounding water molecules. Although the apparent reacting species are a Be atom and hydronium ions, it is shown that the hydration by water molecules is essential in stabilizing the reacting system at every step. The intermediate species corresponding to Be1 is found to be a solvated protonated beryllium ([BeH(H2O)n]+). In the second stage of the oxidation process, the reaction should involve the interaction between the Be1 species and H3O+ to produce an H2 molecule and a hydrated Be2+ ion. The molecular interaction to overcome Coulombic repulsion between these two positively charged species is analyzed in terms of electron-population analysis. It is concluded that the large exothermicity due to the hydration of Be11 leads to the oxidation of solvated Be0 and to the production of a hydrogen molecule. © 1990, American Chemical Society. All rights reserved.