Gas phase properties of bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato) dioxouranium(VI) and bis(2,2,6,6-tetramethyl-3,5-heptanedionato) dioxouranium(VI)
The title compounds (UO/sub 2/(HFA)/sub 2/ and UO/sub 2/(THD)/sub 2/) were found to exist in the gaseous phase as partly dissociated dimers, although UO/sub 2/(HFA)/sub 2/ has previously been shown to be trimeric in the solid state. The enthalpy and entropy changes associated with the dimerization equilibria were determined as ..delta..H/sup 0/ = -48.2 +- 0.6 kJ mol/sup -1/ and ..delta..S = -119 +- 13 J K/sup -1/ mol/sup -1/ for UO/sub 2/(HFA)/sub 2/ and ..delta..H/sup 0/ = -74.5 +- 0.5 kJ mol/sup -1/ and ..delta..S/sup 0/ = -176 +- 12 J K/sup -1/ mol/sup -1/ for UO/sub 2/(THD)/sub 2/. The heats of sublimation (..delta..H/sub sub/) were determined as 147 +- 4 kJ mol/sup -1/ for UO/sub 2/(HFA)/sub 2/ and 126 +- 9 kJ mol/sup -1/ for UO/sub 2/(THD)/sub 2/.
- Research Organization:
- Australian Atomic Energy Commission Research Establishment, Sydney
- OSTI ID:
- 6576786
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 82:20; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACTINIDE COMPLEXES
CHEMICAL REACTIONS
COMPLEXES
DIMERIZATION
DIMERS
ENTHALPY
ENTROPY
FLUIDS
GASES
HIGH TEMPERATURE
PHYSICAL PROPERTIES
POLYMERIZATION
SUBLIMATION HEAT
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION HEAT
URANIUM COMPLEXES
VAPOR PRESSURE