Heat capacity and thermodynamic functions of b-/sup 242/Pu/sub 2/O/sub 3/ from 8 to 350 K. Contributions to the excess entropy
Journal Article
·
· J. Chem. Phys.; (United States)
OSTI ID:6401394
The heat capacity of b-/sup 242/Pu/sub 2/O/sub 3/ was determined by a quasiadiabatic method from 8 to 350 K. The preparation of a single-phase hexagonal plutonium sesquioxide by hydrogen reduction of /sup 242/PuO/sub 2/ at 2250 K is described. A l-type heat capacity anomaly with its peak at 17.65 K was found and this anomaly is associated with an antiferromagnetic transition which is reported by McCart et al. in the preceding paper. An excess entropy of b-/sup 242/Pu/sub 2/O/sub 3/ at 298.15 K is evaluated and shown to approach S/sub excess/ = 2R ln6 = 29.79 J K/sup -1/ mol/sup -1/. In the same manner the previously published experimental entropy of /sup 242/PuF/sub 3/ at 298.15 K was shown to contain an excess entropy contribution approaching S/sub excess/ = R ln6 at 298.15 K. For each compound it was concluded that the excess entropy associated with antiferromagnetic ordering is R ln2 per mol of Pu/sup +3/ ions. For b-/sup 242/Pu/sub 2/O/sub 3/ at 298.15 K the heat capacity C/sup degree//sub p/, entropy S/sup 0/, enthalpy increment H/sup 0/(T)-H/sup 0/(0), and the Gibbs energy divided by temperature (G/sup 0/(T)-H/sup 0/(0))/T are, respectively, (116.98 +- 0.47) J K/sup -1/ mol/sup -1/, (163.02 +- 0.65) J K/sup -1/ mol/sup -1/, (22 572 +- 90) J mol/sup -1/, and (-87.31 +- 0.35) J K/sup -1/ mol/sup -1/. The standard Gibbs free energy of formation of Pu/sub 2/O/sub 3/ at 298.15 K is calculated from available experimental data.
- Research Organization:
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 6401394
- Journal Information:
- J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 74:9; ISSN JCPSA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Thermochemistry of uranium compounds: XVI, Calorimetric determination of the standard molar enthalpy of formation at 298.15 K, low-temperature heat capacity, and high-temperature enthalpy increments of UO{sub 2}(OH){sub 2} {center_dot} H{sub 2}O (schoepite)
Heat capacity and thermodynamic properties of andradite garnet, Ca/sub 3/Fe/sub 2/Si/sub 3/O/sub 12/, between 10 and 1000 K and revised values for. delta. /sub f/G/sub m//sup 0/ (298. 15 K) of hedenbergite and wollastonite
Heat capacities and entropies of rhodochrosite (MnCO/sub 3/) and siderite (FeCO/sub 3/) between 5 and 600 K
Technical Report
·
Sat Aug 01 00:00:00 EDT 1987
·
OSTI ID:60467
Heat capacity and thermodynamic properties of andradite garnet, Ca/sub 3/Fe/sub 2/Si/sub 3/O/sub 12/, between 10 and 1000 K and revised values for. delta. /sub f/G/sub m//sup 0/ (298. 15 K) of hedenbergite and wollastonite
Journal Article
·
Sat Aug 01 00:00:00 EDT 1987
· Geochim. Cosmochim. Acta; (United States)
·
OSTI ID:5099802
Heat capacities and entropies of rhodochrosite (MnCO/sub 3/) and siderite (FeCO/sub 3/) between 5 and 600 K
Journal Article
·
· Am. Mineral.; (United States)
·
OSTI ID:7010889
Related Subjects
36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ACTINIDE COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
ENERGY
ENTROPY
EXPERIMENTAL DATA
FREE ENTHALPY
INFORMATION
LOW TEMPERATURE
MEDIUM TEMPERATURE
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLUTONIUM COMPOUNDS
PLUTONIUM OXIDES
REDUCTION
SPECIFIC HEAT
THERMODYNAMIC PROPERTIES
TRANSURANIUM COMPOUNDS
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ACTINIDE COMPOUNDS
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
ENERGY
ENTROPY
EXPERIMENTAL DATA
FREE ENTHALPY
INFORMATION
LOW TEMPERATURE
MEDIUM TEMPERATURE
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
PLUTONIUM COMPOUNDS
PLUTONIUM OXIDES
REDUCTION
SPECIFIC HEAT
THERMODYNAMIC PROPERTIES
TRANSURANIUM COMPOUNDS
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE