Water Release from Pyrophyllite during the Dehydroxylation Process Explored by Quantum Mechanical Simulations Molina Montes, María Ester Donadio, Davide Hernández Laguna, Alfonso Parrinello, Michele Sainz Díaz, Claro Ignacio We have investigated one of the most controversial aspects of the dehydroxylation–rehydroxylation process of dioctahedral 2:1 phyllosilicates, that is the release of water from the internal structure of the mineral. We simulate the release of water from a periodic crystal model of pyrophyllite by Car–Parrinello molecular dynamics based on Density Functional Theory. The metadynamics algorithm is employed to accelerate activated processes and compute free energy surfaces. We found that, in spite of the strong hydrogen bonds anchoring water molecules in the tetrahedral cavity, the energy barrier for water release is lower than that for the chemical formation of water molecules from the hydroxyl groups. We then conclude that water release is not the rate-limiting step of the dehydration mechanism. 2024-02-12T08:31:02Z 2024-02-12T08:31:02Z 2013-03-20 journal article J. Phys. Chem. C 2013, 117, 15, 7526–7532 https://hdl.handle.net/10481/88991 10.1021/jp310739y eng http://creativecommons.org/licenses/by-nc-nd/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License American Chemical Society