Sixty Years of the van der Waals and Platteeuw Model for Clathrate Hydrates-A Critical Review from Its Statistical Thermodynamic Basis to Its Extensions and Applications.

In light of the 60-year anniversary of the publishing of "Clathrate Solutions" by van der Waals and Platteeuw in 2019, we present a critical review of the famed solid solution model first disclosed in 1959. First, we lay out the groundwork in the 1950s aimed at the development of a phenomenological approach to clathrate modeling. Then we review the statistical thermodynamics fundamentals of the model, considering van der Waals and Platteeuw's earlier works, to obtain a consistent interpretation of the model. We turn our focus to clathrate hydrates and discuss the major contributions that led to the current state-of-the-art of gas hydrate thermodynamic modeling. Finally, we present some of the areas in clathrate thermodynamics that we foresee as the new frontiers in this subject. We expect this review to help newcomers to clathrate science in elucidating some subtle aspects of the model and to intrigue clathrate experts with a fresh look on this well-established solid solution model.