Experimental heat capacities of LaNi/sub 5/,. cap alpha. -LaNi/sub 5/H/sub 0. 36/, and. beta. -LaNi/sub 5/H/sub 6. 39/ from 5 to 300 /sup 0/K. Thermodynamic properties of the LaNi/sub 5/--H/sub 2/ system

Journal Article · Mon Sep 15 00:00:00 EDT 1980 · J. Chem. Phys.; (United States)

OSTI ID:5079261

Ohlendorf, D; Flotow, H E

The heat capacities of LaNi/sub 5/, ..cap alpha..-LaNi/sub 5/H/sub 0.36/, and ..beta..-LaNi/sub 5/H/sub 6.39/ were measured from 5 to 300 /sup 0/K, and in the case of LaNi/sub 5/ also from 300 to 350 /sup 0/K. Various special techniques and unusual circumstances involved in the measurements and calculations are described. A slight enhancement of the heat capacity of ..beta..-LaNi/sub 5/H/sub 6.39/ was observed in the temperature range 120 to 160 /sup 0/K. The standard entropies of LaNi/sub 5/, ..cap alpha..-LaNi/sub 5/H/sub 0.36/, and ..beta..-LaNi/sub 5/H/sub 6.39/ at 298.15 /sup 0/K were found to be 209.9 +- 0.5, 214.1 +- 0.5, and 271.7 +- 0.7 J /sup 0/K/sup -1/ mole/sup -1/, respectively. These results together with other thermochemical data were used to calculate the entropy and enthalpy of formation of ..beta..-LaNi/sub 5/H/sub 6.39/ at 298.15 /sup 0/K. The partial molar entropy of hydrogen in ..beta..-LaNi/sub 5/H/sub 6.39/ was derived from our results and used to estimate the configurational entropy at 298.15 /sup 0/K.

• Research Organization: Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
• DOE Contract Number: W-31-109-ENG-38
• OSTI ID: 5079261
• Journal Information: J. Chem. Phys.; (United States), Vol. 73:6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
LANTHANUM ALLOYS
ENTROPY
FORMATION HEAT
SPECIFIC HEAT
LANTHANUM HYDRIDES
NICKEL BASE ALLOYS
NICKEL HYDRIDES
ABSORPTION
BINARY ALLOY SYSTEMS
EXPERIMENTAL DATA
INTERMETALLIC COMPOUNDS
LOW TEMPERATURE
MEDIUM TEMPERATURE
THERMODYNAMIC PROPERTIES
ULTRALOW TEMPERATURE
VERY LOW TEMPERATURE
ALLOY SYSTEMS
ALLOYS
DATA
ENTHALPY
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
LANTHANUM COMPOUNDS
NICKEL ALLOYS
NICKEL COMPOUNDS
NUMERICAL DATA
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
RARE EARTH COMPOUNDS
REACTION HEAT
TRANSITION ELEMENT COMPOUNDS
360104* - Metals & Alloys- Physical Properties