In the crystal of the title compound, the quinone fragment of the host (1) participates in weak D-A interactions with a neighboring naphthalene moiety of 1 and with the guest molecule via fairly short intermolecular face-to-face contacts. An intermolecular electrostatic interaction between a quinone-oxygen atom and a neighboring quinone ring is suggested by short O...C contacts. There exist sev...

Using a volumetric technique, the deuterium solubility, X, in heavy water (L), low-pressure hexagonal ice (I h), and high-pressure cubic clathrate ice (sII) is studied at deuterium pressures up to 1.8 kbar and temperatures from -40 to +5 degrees C. The triple point of the L + I(h) + sII equilibrium is located at P = 1.07(3) kbar and T = -4.5(8) degrees C. The molar ratios D2/D2O of phases at th...

The observation of intrinsic structural, electrical, and thermal properties from measurements on single-crystal specimens of clathrate-II Na24Si136 is reported, revealing metallic conduction in agreement with electronic structure calculations. Low-temperature heat capacity measurements corroborate a substantial electronic density of states at the Fermi level, and reveal an Einstein-like mode th...

We have performed (69)Ga, (71)Ga, and (137)Ba NMR on Ba8Ga16Ge30, a clathrate semiconductor which has been of considerable interest due to its large figure of merit for thermoelectric applications. In measurements from 4 K to 450 K, we used measurements on the two Ga nuclei to separate the magnetic and electric quadrupole hyperfine contributions and thereby gain information about the metallic a...

Using a volumetric technique, a T-P diagram of phase transformations between the hydrogen-rich clathrate hydrate (sII phase), hydrogen-filled ice II (C(1) phase), and the liquid (L) is studied in the H(2)O-H(2) system at pressures up to 4.7 kbar and temperatures from -22 to +15 degrees C. The volume and entropy effects of these transformations are established in the vicinity of the triple point...

Among alternatives to fossil fuels, H2 gas is considered to be one of the most promising energy resources owing to its advantages of being nonpolluting and abundant in nature. In particular, fuel cells are currently receiving much attention for utilization of H2 gas in the development of both stationary and mobile power generators. H2 gas, however, inevitably has some safety concerns owing to t...