FTIR spectra of the hydrolysis of uranium hexafluoride

The hydrolysis of uranium hexafluoride has been examined with infrared spectroscopy under three different reaction conditions. First, UF₆ was codeposited with water in excess argon at 12 K. The FTIR spectra of UF₆/H₂O mixtures revealed several product absorptions due to the perturbed v₁, v₂, and v₃ modes of H₂O as well as the v₃ mode of UF₆. These new absorptions have been assigned to the anti-hydrogen-bonded 1:1 complex, UF₆-OH₂. Photolysis of this weak complex produced a doublet at 868.2 and 857.1 cm^-1, which has been assigned to the UOF₄. Next, solid films of UF₆/H₂O mixtures were prepared at 12 K and slowly annealed at 242 K. The reaction profile of the UF₆ hydrolysis from UF₆ (or UF₆-OH₂) to UOF₄ to UO₂F₂ was obtained. Finally, UF₆ and H₂O were reacted at low pressures and ambient temperatures in a new IR gas cell. While no gaseous uranium oxyfluorides were detected, the final product distribution inside the gas cell did indicate that the fluorinated nickel surface served as a catalyst for the UF₆ hydrolysis.