The examination of ambient thermodynamic conditions suggests that clathrate hydrates could exist in the Martian permafrost, on the surface and in the interior of Titan, as well as in other icy satellites. Clathrate hydrates are probably formed in a significant fraction of planetesimals in the solar system. Thus, these crystalline solids may have been accreted in comets, in the forming giant pla...

It has long been known that crystalline hydrates are formed by many simple gases that do not interact strongly with water, and in most cases the gas molecules or atoms occupy 'cages' formed by a framework of water molecules. The majority of these gas hydrates adopt one of two cubic cage structures and are called clathrate hydrates. Notable exceptions are hydrogen and helium which form 'exotic' ...

Recent observations have evidenced traces of methane (CH4) heterogeneously distributed in the martian atmosphere. However, because the lifetime of CH4 in the atmosphere of Mars is estimated to be around 300–600 years on the basis of photochemistry, its release from a subsurface reservoir or an active primary source of methane have been invoked in the recent literature. Among the existing scenar...

Clathrate hydrates are typically stabilized by suitably sized hydrophobic guest molecules. However, it has been experimentally reported that isomers of amyl-alcohol C5H11OH can be enclosed into the 5(12)6(4) cages in structure II (sII) clathrate hydrates, even though the effective radii of the molecules are larger than the van der Waals radii of the cages. To reveal the mechanism of the anomalo...

Due to their high charge-storage capacity (i.e. >3000 mAhg ), there has been much research activity in the development of silicon-based anodes for high-energy-density lithium-ion batteries. In recent years, there has been immense interest in understanding the electrochemical, 2] structural, and mechanical properties of both diamond cubic (c-Si) and amorphous silicon (a-Si) under reaction with l...

The stability of the recently characterized type II hydrogen clathrate [Mao, W. L., Mao, H.-K., Goncharov, A. F., Struzhkin, V. V., Guo, Q., et al. (2002) Science 297, 2247-2249] with respect to hydrogen occupancy is examined with a statistical mechanical model in conjunction with first-principles quantum chemistry calculations. It is found that the stability of the clathrate is mainly caused b...

Clathrate compounds combine aesthetic beauty of their crystal structures with promising thermoelectric properties that have made them one of the most explored family of compounds deemed as base for thermoelectric generators for midand hightemperature application. This chapter surveys crystal and electronic structure and structure-related transport properties of selected types of clathrates and ...

We present an ab initio study of the structural and electronic properties of the recently synthesized I(8)@Si-46 clathrate which is shown to be a degenerate p-type doped system. The intercalation significantly opens the band gap to a 1.75 eV value within the density functional theory. We study further the intercalation by other neighboring elements. A quasiparticle study reveals that such syste...

The host xanthenol compound forms a 1:1 clathrate with dioxane, namely 9-(1-naphthyl)-9H-xanthen-9-ol-1,4-dioxane, C23H16O2.C4H8O2. The structure of this clathrate is reported, along with a study of the kinetics of desolvation and the determination of an activation energy. The guest molecules are stabilized by O(host)-H...O(guest) hydrogen bonds [O-H = 0.968 (2) A, O...O = 2.7532 (13) A and O-H...

The dielectric permittivity of the orientational glass methanol(x50.73)-b-hydroquinone-clathrate has been studied as function of temperature and waiting time using different temperature-time protocols. We study aging, rejuvenation, and memory effects in the glassy phase and discuss similarities and differences to aging in spin glasses. We argue that the diluted methanol-clathrate, although conc...