Elucidation of hydrolysis reaction mechanism of tungsten hexafluoride (WF₆) using first-principles calculations

We identify hydrolysis reaction mechanism of water-reactive WF₆ and its accompanying intermediates using first-principles calculations. For the purpose, we evaluate activation and free energy diagrams of elementary reaction steps. We find that WF₆, WOF₄, and WO₂F₂ form stable adducts, which quickly reacts with H₂O by substituting the ligand F. Gaseous WOF₄, WO₂F₂, WO₃ are predicted as unstable in the increasing order, but polymerization reduces their instability, leading to solidification. In overall reaction, WOF₄ hydrolysis is the bottleneck due to significantly higher activation barrier of trans isomeric complex than cis counterpart.