Hydrophobic Hydration and the Formation of a Clathrate Hydrate

We report a direct comparison of the local structure of the hydrophobic hydration of krypton in both the liquid and solid states by the extended x-ray absorption fine structure spectroscopy technique. The evolution of an ordered hydration shell of the nonpolar gas moiety is followed as the liquid to solid phase transition progresses. The formation of a clathrate cage structure from the more disordered liquid state hydration shell is clearly demonstrated.