Possible Formation of H₃O⁺ Cations Due to Aluminum Fluoride Interactions with Water

The isomeric structures formed by the aluminum fluoride (AlF₃) system and surrounding water molecules were theoretically examined by employing MP2 and CCSD(T) methods and the aug-cc-pVDZ basis set together with the polarized continuum solvation model within a self-consistent reaction field treatment. The calculations performed for the AlF₃·n(H₂O) systems (n = 1-6) revealed that facial and meridional octahedral structures correspond to the lowest energy isomers for the AlF₃·4H₂O, AlF₃·5H₂O, and AlF₃·6H₂O systems, whereas the isomers containing the H₃O⁺ and AlF₃OH^- fragments were predicted to be less stable by only 5-7 kcal/mol, which indicates the possible formation of the hydronium cations in such systems even at room temperature.