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Structural and dynamic studies of Pr(11BH4)3

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  • Angelina Gigante, University of Geneva, Swiss Federal Laboratories for Materials Science and Technology (Empa)
  • ,
  • Seyedhosein Payandeh, Swiss Federal Laboratories for Materials Science and Technology (Empa)
  • ,
  • Jakob B. Grinderslev
  • Michael Heere, Karlsruhe Institute of Technology
  • ,
  • Jan Peter Embs, Paul Scherrer Institute
  • ,
  • Torben R. Jensen
  • Tatsiana Burankova, Paul Scherrer Institute
  • ,
  • Arndt Remhof, Swiss Federal Laboratories for Materials Science and Technology (Empa)
  • ,
  • Hans Hagemann, University of Geneva

Rare earth borohydrides RE (BH4)3 are studied in the context of energy storage, luminescence and magnetic applications. We have investigated the structural behavior of praseodymium borohydride Pr (11BH4)3 containing 11B isotope because of the previously reported negative thermal expansion. Differential scanning calorimetry (DSC), in-situ variable temperature synchrotron radiation powder X-ray diffraction (SR-PXD) and infrared studies reveal that Pr (11BH4)3 undergoes to a volume contraction during the phase transition from alpha α-Pr (11BH4)3 to rhombohedral r-Pr (11BH4)3 phase upon heating to 493 K. Surprisingly, the phase transition persists upon cooling at room temperature. Vibrational analysis also shows that the stretching frequency of BH4 anion does not change upon heating which indicates that the B–H bond length remains constant during the structural phase transition from α-Pr (11BH4)3 to r-Pr (11BH4)3 phase. Additionally, the energy barrier of reorientation motion of the BH4 anion in the α-phase was estimated to be ca 23 kJ/mol by quasi-elastic neutron scattering (QENS) and Raman spectroscopy.

Original languageEnglish
JournalInternational Journal of Hydrogen Energy
Pages (from-to)32126-32134
Number of pages9
Publication statusPublished - Sept 2021

Bibliographical note

Publisher Copyright:
© 2021 The Authors

    Research areas

  • Negative thermal expansion, QENS, Rare earth borohydrides, SR-PXD, Vibrational spectroscopy

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