Thermodynamics of the lanthanide trifluorides. III. The heat capacity of neodymium trifluoride, NdF/sub 3/, from 5 to 350 /sup 0/K

Journal Article · Thu Nov 15 04:00:00 EST 1979 · J. Chem. Phys.; (United States)

OSTI ID:5777176

Lyon, W G; Osborne, D W; Flotow, H E

The heat capacity of a well-characterized sample of NdF/sub 3/ was measured by aneroid adiabatic calorimetry from 5 to 350 /sup 0/ K. The following results were determined at 298.15 /sup 0/ K: the heat capacity, C/sub p/= (92.42 +- 0.09) J /sup 0/ K/sup -1/ mole/sup -1/; the entropy, S/sup 0/= (120.79 +- 0.12) J /sup 0/K/sup -1/ mole/sup -1/; the enthalpy increment, (H /sup 0/ (298.15 /sup 0/K)-H/sup 0/ (0))=17 360 +- 17 J mole/sup -1/; and the Planck function, -(G/sup 0/ (298.15/sup 0/ K)-H /sup 0/ (0))/T= (62.56 +- 0.06) J /sup 0/ K/sup -1/ mole/sup -1/. The values of the last three functions were adjusted for the removal of the degeneracy associated with the ground-state Kramer's doublet of Nd/sup +3/. A table of recommended thermal functions of NdF/sub 3/ from 400 to the melting temperature, 1650 /sup 0/K is presented. The excess heat capacity due to the internal electronic energy levels of Nd/sup +3/ was calculated from spectroscopic data and also from calorimetric results and the two calculations were found to be in reasonable agreement.

• Research Organization: Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
• OSTI ID: 5777176
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 71:10; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
CALORIMETRY
ENTHALPY
ENTROPY
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
LOW TEMPERATURE
NEODYMIUM COMPOUNDS
NEODYMIUM FLUORIDES
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SPECIFIC HEAT
THERMODYNAMIC PROPERTIES
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE