HEAT CAPACITY OF URANIUM TETRAFLUORIDE FROM 1.3 TO 20 K AND THE THERMODYNAMIC FUNCTIONS TO 300 K. CALORIMETER FOR THE RANGE 0.8 TO 20 K

Journal Article · Mon Aug 01 04:00:00 EDT 1960 · Journal of Chemical Physics (U.S.)

DOI:https://doi.org/10.1063/1.1731154· OSTI ID:4173418

Burns, J D; Osborne, D W; Westrum, Jr, E F

The heat capacity of uranium tetrafluoride was determined from 1.3 to 20 deg K in an isothermal calorimeter with an integral gas thermometer and vapor- pressure bulb for calibration of a carbon resistance thermometer. The enthalpy, entropy, and free-energy functions were evaluated from these data and previous measuremerts at higher temperatures. At 298.15 deg K the values of S deg , (H deg - H/sub 0/ deg )/T, and -(F deg - H/sub 0/ deg )/T are 36.25 plus or minus 0.04, 18.08 plus or minus 0.02, and 18.17 plus or minus 0.02 cal mole/sup -1/ deg -1/ for uranium tetrafluoride. A Schottky-type anomaly occurs in the heat capacity at 6.4 deg K, presumably as a consequence of ligand-field splitting of the electronic energy levels. (auth)

• Research Organization: Argonne National Lab., Ill.
• Sponsoring Organization: USDOE
• NSA Number: NSA-14-021445
• OSTI ID: 4173418
• Journal Information: Journal of Chemical Physics (U.S.), Journal Name: Journal of Chemical Physics (U.S.) Vol. Vol: 33; ISSN JCPSA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CALORIMETERS
CHEMISTRY
HEAT CAPACITY
LOW TEMPERATURE
MEASURED VALUES
SCHOTTKY DEFECTS
SPECIFIC HEAT
THERMODYNAMICS
THERMOMETERS
URANIUM TETRAFLUORIDE