Theoretical Mechanism Study of UF6 Hydrolysis in the Gas Phase (II)

In our previous work (J. Phys. Chem. A 2008, 112, 8877.), we found theoretical evidence indicating UF5OH is an intermediate produced in the first step of UF6 hydrolysis. In this work, we explored the probable reaction channels starting from UF5OH + UF6 and UF5OH + UF5OH systems using relativistic density functional theory calculations. Initially, the two uranium containing species associate to form complex UF6 center dot UF5OH or dimer (UF5OH)(2) through hydrogen bonding. The energy released is 12-16 kcal/mol, which may promote further reactions. After H2O or HF are eliminated from the complex or dimer, compounds containing U-C-U bond are produced. These compounds are potentially feasible to associate into larger clusters or solidify. Relative to the isolated initial species, the energies of the final products are -6 to -13 kcal/mol lower, indicating that the reactions may spontaneously proceed. The calculated IR spectra features can be used to indicate the formation and interaction type of the intermediates and products.