A model for the formation and stabilization of charged water clathrates

Abstract

A model for the formation and stabilization of charged water clathrates is presented which accounts for observed anomalies in H⁺(H₂O)_n ion distributions. These anomalies are observed in both ion cluster and neutral expansions and are consistent with the sizes expected for clathrate ions. That the same sizes are observed in both ion cluster and neutral expansions strongly suggests that a rapid ionic process is responsible for their formation. The proposed model is based on the high mobility and bonding effects of the ’’excess’’ proton in water. Computer simulations suggest that ’’excess’’ proton movement in a water clathrate would be suitable for stabilizing the clathrate structure as well as giving it access to a large number of nearly degenerate proton configurations. The formation of clathrates in charged water clusters of proper size can be ascribed to the following: rapid ’’excess’’ proton movement, a strong preference of the H₃O⁺ for a 3‐coordinate bonding structure (which is compatible with hydrogen bonding), and finally, relatively slow processes leading to thermal disorder.