Thermochemical studies of the gaseous uranium chlorides

Journal Article · Wed Feb 01 04:00:00 EST 1984 · J. Chem. Phys.; (United States)

OSTI ID:5268098

Lau, K H; Hildenbrand, D L

The gaseous uranium halides UCl, UCl/sub 2/, UCl/sub 3/, UCl/sub 4/, and UCl/sub 5/ were generated under equilibrium conditions using several types of effusive beam sources, and were identified and characterized thermochemically by mass spectrometry. Five independent gaseous equilibria involving these species were studied in sufficient depth so that both reaction enthalpy and entropy changes could be evaluated accurately from second law analysis. The enthalpy data yield the sequence of bond dissociation energies at 298 K in kcal/mol: D/sup 0/ (U--Cl) = 108; D/sup 0/ (ClU--Cl) = 117; D/sup 0/ (Cl/sub 2/U--Cl) = 117; D/sup 0/ (Cl/sub 3/U--Cl) = 101; and D/sup 0/ (Cl/sub 4/U--Cl) = 50, all +- 2 kcal/mol. As expected, the absolute entropies of the gaseous chlorides show that the electronic partition functions of the lighter species are substantial at the experimental temperatures, leading to electronic entropies of 5--7 cal/deg mol at about 2100 K.

• Research Organization: SRI International, Menlo Park, California 94205
• OSTI ID: 5268098
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 80:3; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ACTINIDE COMPOUNDS
CHEMICAL BONDS
CHLORIDES
CHLORINE COMPOUNDS
DATA
DISSOCIATION HEAT
ENTHALPY
ENTROPY
EQUILIBRIUM
EXPERIMENTAL DATA
FLUIDS
FORMATION HEAT
GASES
HALIDES
HALOGEN COMPOUNDS
INFORMATION
MASS SPECTROSCOPY
NUMERICAL DATA
PHYSICAL PROPERTIES
REACTION HEAT
SPECTROSCOPY
THERMODYNAMIC PROPERTIES
URANIUM CHLORIDES
URANIUM COMPOUNDS