The Aquation of Po(IV): A Quantum Chemical Study.

The aim of this work is to present theoretical results of the hydration of the Po(IV) in solution. Particular attention is paid to the level of calculation needed to properly describe the system under study: Po(IV) coordination number in the first hydration shell and the nature of the polonium‐water bonding. The hydration number of the Po(IV) is found to be in solution between 8 and 9 and the solvation free energy around −1450 kcal/mol. The Po‐H2O bonding is dominated by the strong electrostatic contribution although the peculiar geometry adopted by the different hydrates is due to covalent contributions. This involves the empty 6p orbital of the polonium ion and one lone pair on the oxygen atom of the water molecule. No role of the 6s orbital of the polonium ion is detected.