Chemistry of lower valent actinide halides. Final report

Technical Report · Wed Jan 01 04:00:00 EST 1992

DOI:https://doi.org/10.2172/10160040· OSTI ID:10160040

Lau, K H; Hildenbrand, D L

This research effort was concerned almost entirely with the first two members of the actinide series, thorium and uranium, although the work was later extended to some aspects of the neptunium-fluorine system in a collaborative program with Los Alamos National Laboratory. Detailed information about the lighter actinides will be helpful in modeling the properties of the heavier actinide compounds, which will be much more difficult to study experimentally. In this program, thermochemical information was obtained from high temperature equilibrium measurements made by effusion-beam mass spectrometry and by effusion-pressure techniques. Data were derived primarily from second-law analysis so as to avoid potential errors in third-law calculations resulting from uncertainties in spectroscopic and molecular constants. This approach has the additional advantage of yielding reaction entropies that can be checked for consistency with various molecular constant assignments for the species involved. In the U-F, U-Cl, and U-Br systems, all of the gaseous species UX, UX{sub 2}, UX{sub 3}, UX{sub 4}, and UX{sub 5}, where X represents the halogen, were identified and characterized; the corresponding species ThX, ThX{sub 2}, ThX{sub 3}, and ThX{sub 4} were studied in the Th-F, Th-Cl, and Th-Br systems. A number of oxyhalide species in the systems U-0-F, U-0-Cl, Th-0-F, and Th-O-Cl were studied thermochemically. Additionally, the sublimation thermodynamics of NpF{sub 4}(s) and NpO{sub 2}F{sub 2}(s) were studied by mass spectrometry.

• Research Organization: SRI International, Menlo Park, CA (United States). Materials Research and Chemical Engineering Lab.
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG03-89ER13986
• OSTI ID: 10160040
• Report Number(s): DOE/ER/13986--T1; ON: DE92017031
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201
400702
ACTINIDE COMPOUNDS
ATOMIC IONS
BROMIDES
CHEMICAL AND PHYSICOCHEMICAL PROPERTIES
CHLORIDES
ENTROPY
FLUORIDES
IONIZATION POTENTIAL
MASS SPECTROSCOPY
NEPTUNIUM FLUORIDES
OXYCHLORIDES
OXYFLUORIDES
PHYSICAL PROPERTIES
PROGRESS REPORT
PROPERTIES OF RADIOACTIVE MATERIALS
RUTHENIUM FLUORIDES
THERMOCHEMICAL PROCESSES
THERMODYNAMIC PROPERTIES
THORIUM COMPOUNDS
URANIUM COMPOUNDS
VAPOR PRESSURE