Dissociation Mechanisms of Dissolved Alkali Silicates in Sodium Hydroxide

Recent accelerated simulations of the decondensation of silicates by sodium hydroxide open a window on understanding complex mechanisms of the depolymerization of silicate chains. Herein, complex mechanisms of decondensation that involve two water molecules (or OH^- groups) are unveiled. The study of two different solutions, having the same chemical composition but in different concentration, help one to draw more general conclusions on the dissociation mechanism in silicate solutions. We find that the dissociation is not always assisted by single water molecules but that in about 20% of the cases two water molecules (or OH^-) are present in the near environment. The results underline the importance to consider explicit water solvent in which water molecules are reactive. (authors)