Thermal conductivity of solids and liquids under pressure is covered in this review. Experimental techniques are critically considered and compared, and an introduction to theory is provided. Results are presented and discussed for ionic crystals, normal molecular crystals, plastic crystal phases, clathrate hydrates, polymers and glassformers, liquids, covalent and semiconducting crystals, rocks and metals. Special attention is given to isochoric conditions', change of crystal structure and molecular orientational disorder. Available reliable measurements at pressures up to a few GPa indicate the need for theoretical development, especially in connection with molecular crystals and ferromagnetic metals.

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RUSSELL G. Ross and PER ANDERSSON. Can. J. Chem. 60,881 (1982). Solid phases in the tetrahydrofuran-water (THF-H20) system were investigated in the temperature range 100-260K and at pressures up to 1.5 GPa. Thermal conductivity, h, and heat capacity per unit volume, pc,, were measured, using the transient hot-wire method. We made measurements on solid phases having nominal compositions THF.17H20, THF,7.1H20, and THF.4.6H20, which we refer to as phases a , P, and y , respectively. Phase a is known to be a structure I1 clathrate hydrate, and h for this phase was found to be similarto other crystalline solids which areglass-like in relation to their thermal properties. Low-energy excitations are known to be relevant to the properties of glass-like solids, and, in the case of phase a , were probably rotational vibrations of the THF guest molecules. Phase was similar, and we inferred that it was probably a structure I clathrate hydrate. Phase y behaved nearly like a normal crystal phase at low temperatures, but h became almost independent of temperature near melting. At 1.1 GPa and 130 K, we found evidence that phase a transformed, on pressurization, to a metastable modification which may be a new high-density form of clathrate hydrate. The astrophysical implications of our results were mentioned briefly. RUSSELL G. ROSS et PER ANDERSSON. Can. J. Chem. 60, 881 (1982). On a ttudie les phases solides dans le systkme tetrahydrofuranne-eau (THF-H20) dans un intewalle de temperature allant de 100 a 260 K et des pressions allant jusqu'a 1,s GPa. On a mesure la conductivite thermique, h, et la capaciti calorifique par unite de volume, pc,, en utilisant la methode du fil chaud transitoire. Nous avons effectue ces mesures sur des phases solides ayant des compositions nominales de THF.17H20, THF.7,1H20 et THF4,6H20 que nous disignons respectivement comme phases a,p et y.On sait que la phase a a une structure I1 d'hydrate de clathrate et on a trouvt que, pour cette phase, h est semblable a celui d'autres solides cristallins qui ressemblent des verres si I'on tient compte de leurs proprietes thermiques. On sait que les excitations de faible energie sont relikes aux proprietes des solides ressemblant a des verres et, dans le cas de la phase a, ce sont probablement des vibrations-rotations des molecules-h8tes de THF. La phase P est semblable et nous en diduisons qu'elle a probablement une structure I d'hydrate de clathrate. La phase y se comporte presque comme une phase cristalline normale a basse temperature, mais h devient presqu'indtpendant de la temperature au voisinage du point de fusion. A 1,l GPa et 130 K, nous avons trouve des indications a l'effet que la phase a se transforme, sous pression, en une forme metastable qui peut &tre une nouvelle forme d'hydrate de clathrate a haute densite. Nous mentionnons brikvement les implications astrophysiques de nos resultats.[Traduit par le journal]

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