Hydrogenation Entropies of the ZrMn2+y System

  • F. Pourarian
  • V. K. Sinha
  • W. E. Wallace
  • A. T. Pedziwiatr
  • R. S. Craig
Part of the NATO Conference Series book series (NATOCS, volume 6)


Hydrogenation of Mn-containing intermetallics leads to striking changes in magnetic properties. For example, Th6Mn23 is a Pauli paramagnetic but becomes ferrimagnetic upon hydrogenation. Vapor pressure studies of ZrMn2+y hydrides. have suggested unusual ΔH and ΔS values for hydrogen release. The values are about 40 and 50%, respectively, lower than the corresponding values for the paradigm hydride material LaNi5H6. The unusual thermodynamics could originate with either a large magnetic contribution or irreversibility for the system. Recent calorimetric measurements indicate that irreversibility is the major factor. Entropies of absorbed hydrogen derived from the calorimetric results are about 17 J/K g.atom of H, which is in good agreement with the computed values, 18.3 J/K g. atom H.


Configurational Entropy Hydrogen Release Hydrogen Storage Material Hydrogen Capacity Vibrational Contribution 
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Copyright information

© Plenum Press, New York 1983

Authors and Affiliations

  • F. Pourarian
    • 1
  • V. K. Sinha
    • 1
  • W. E. Wallace
    • 1
  • A. T. Pedziwiatr
    • 1
  • R. S. Craig
    • 1
  1. 1.Department of ChemistryUniversity of PittsburghPittsburghUSA

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