Chemistry of gaseous lower halides of uranium. Technical progress report, 1 September 1979-1 April 1980

Technical Report · Tue Apr 15 04:00:00 EST 1980

DOI:https://doi.org/10.2172/6742743· OSTI ID:6742743

Hildenbrand, D L

The gaseous uranium species UF, UF/sub 2/, UF/sub 3/, and UF/sub 4/ were generated in effusion cell beams by vaporization of UF/sub 4/(s) under reducing conditions, and they were identified and studied by mass spectrometry. From extensive second-law studies of reaction equilibria involving these species and several reaction partners used as reference standards, the individual bond dissociation energies and standard enthalpies of formation of the U-F species were derived. Reaction entropies derived from the slope data indicate that the electronic entropies of the U-F species are substantial, and are comparable to or larger than that of atomic uranium. Additional thermochemical measurements were made to establish the properties of several Ag and Cu monohalides that have been or will be used as reference standards in the uranium halide measurements. From studies of the sublimation and decomposition of uranyl fluoride, UO/sub 2/F/sub 2/(s), the enthalpy of sublimation of UO/sub 2/F/sub 2/(g), has been determined, and another gaseous oxyfluoride, UOF/sub 4/(g), has been tentatively identified. The gaseous products of decomposition of UO/sub 2/F/sub 2/(s) observed by mass spectrometry differ from those postulated by other investigators, indicating that the mechanism of decomposition has not been clearly established. A search of the thermochemical literature on uranium halides has been completed.

• Research Organization: SRI International, Menlo Park, CA (USA)
• DOE Contract Number: AT03-79ER10414
• OSTI ID: 6742743
• Report Number(s): DOE/ER/10414-T1
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
ACTINIDE COMPOUNDS
ENTHALPY
ENTROPY
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
FORMATION HEAT
GASES
HALIDES
HALOGEN COMPOUNDS
MASS SPECTROSCOPY
OXYFLUORIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
REACTION HEAT
RESEARCH PROGRAMS
SPECTROSCOPY
SUBLIMATION HEAT
THERMODYNAMIC PROPERTIES
TRANSITION HEAT
URANIUM COMPOUNDS
URANIUM FLUORIDES
URANIUM TETRAFLUORIDE
URANYL COMPOUNDS
URANYL FLUORIDES