Many simple gases that do not interact strongly with water form crystalline hydrates in which the gas molecules or atoms occupy ‘cages’ formed by a framework of water molecules. These clathrate hydrates are stabilised by hydrophobic gas-water interactions and are model systems for the study of these interactions. Many gas hydrates also occur in nature and their properties provide a basis for mo...

[1] Explanations for the plume of gas, water vapor and ice particles jetting from rifts in Enceladus’ south polar region include boiling of liquid water and dissociation of clathrate hydrates. In either case, production of the plume may be quasi-static or tidally controlled, with implications for the interior structure and composition of Enceladus. Previous quantification of the clathrate expla...

The effective thermal conductivity of the powder samples of xenon hydrate was measured in the interval 2–170 K using the steady-state method. The thermal conductivity of the homogeneous Xe clathrate hydrate was estimated from the effective thermal conductivity using an empirical expression. The applicability of the formula was checked by comparing two powder samples with different grain size an...

Clathrate hydrates of methane and other small alkanes occur widespread terrestrially in marine sediments of the continental margins and in permafrost sediments of the arctic. Quantitative study of natural clathrate hydrates is hampered by the difficulty in obtaining pristine samples, particularly from submarine environments. Bringing samples of clathrate hydrate from the seafloor at depths with...

High pressure and low temperature experiments with CO(2) hydrate were performed using diamond anvil cells and a helium-refrigeration cryostat in the pressure and temperature range of 0.2-3.0 GPa and 280-80 K, respectively. In situ x-ray diffractometry revealed that the phase boundary between CO(2) hydrate and water+CO(2) extended below the 280 K reported previously, toward a higher pressure and...

The material design of type-VIII clathrate Si46 is presented based on first principles. The structural, electronic, elastic, vibrational, and thermodynamic properties of this hypothetical material are presented. Our results predict that type-VIII clathrate Si46 is an indirect semiconductor with a bandgap of 1.24 eV. The band structure revealed an interestingly large number of electron pockets n...

INTRODUCTION The accurate prediction of conditions for hydrate formation depends strongly on the availability of good structural information’. For clathrate hydrates, a complete description of structure involves not only the unit cell parameters and average atomic positions, but also the cage occupancies. In order to provide this kind of information, it is necessary to use techniques such as di...

The title compound undergoes two order-disorder transitions between 15 and 299 K, dictated by ordering of the guest molecules in the host cages, and resulting in three related crystal structures. We anticipate behaviour of this kind to be widespread, and speculate that the concept of "the crystal structure" for individual Dianin's clathrates may be elusive.

Experiments were carried out to synthesize and characterize a structure H clathrate hydrate containing CO(2) and 3,3-dimethyl-2-butanone (pinacolone) by means of phase equilibrium and powder X-ray diffraction measurements. Molecular dynamics simulations of this structure H hydrate were performed to understand the nature of guest-host molecular interactions.