Thermodynamics of clathrates with unstable empty host framework. 3. Hydrates of cubic structure 1

Vibrational and thermodynamic properties of cubic structure 1 clathrate hydrate framework and 6Xe·46H2O and 8Xe·46H2O hydrates are studied. Hydrate stability to the external pressure at low temperatures and pressure dependence of the critical temperature of destroying of the hydrate at temperatures near 0 deg C are investigated. At zero pressure and temperatures above -13 deg C empty hydrate framework is found to be thermodynamically unstable (labile). Filling the framework by the guest molecules expands its stability region on the P-T-phase diagram