Thermodynamic study of the thorium-hydrogen system at 700 K

Journal Article · Sun Jun 01 04:00:00 EDT 1980 · High Temp. Sci.; (United States)

OSTI ID:6646452

Picard, C; Kleppa, O J

The partial enthalpies of solution of hydrogen in thorium-hydrogen alloys with H/Th ratios ranging from 0 to 2 have been measured calorimetrically at 700 K. From these data we calculate the standard enthalpy of formation of ThH/sub 2/ at this temperature to be -34.8 kcal mol/sup -1/ with an estimated uncertainty of +- 0.2 kcal mol/sup -1/. This agrees well with values calculated by earlier investigators from plateau pressure equilbrium data. For several alloy compositions within the nearly stoichiometric phase ThH/sub 2/ the equilibrium pressures of hydrogen also were determined. Comparisons of the relative partial Gibbs energies of hydrogen obtained from these equilibrium pressures with corresponding enthalpies from calorimetry provide information on the partial entropy. The partial enthalpy and entropy both change dramatically with composition between H/Th = 1.99 and 2.003.

• Research Organization: Univ. of Chicago, IL
• OSTI ID: 6646452
• Journal Information: High Temp. Sci.; (United States), Journal Name: High Temp. Sci.; (United States) Vol. 12:2; ISSN HITSA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ACTINIDE COMPOUNDS
CALORIMETRY
ELEMENTS
ENERGY
ENTHALPY
FORMATION FREE ENTHALPY
FREE ENTHALPY
HIGH TEMPERATURE
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
NONMETALS
PHYSICAL PROPERTIES
SOLUTION HEAT
THERMODYNAMIC PROPERTIES
THORIUM COMPOUNDS
THORIUM HYDRIDES