Charge density measurement in MgH2 by synchrotron X-ray diffraction

T. Noritake, S. Towata, M. Aoki, Y. Seno, Y. Hirose, E. Nishibori, Masaki Takata, M. Sakata

Research output: Contribution to journalConference article

39 Citations (Scopus)

Abstract

Magnesium and its alloys are considered one of the most promising materials for reversible hydrogen storage. However, their high thermodynamic stability is unfavorable for dehydrogenation processes. In order to improve their properties, understanding of the bonding nature of Mg and H is essential. In this study, we reveal the precise experimental charge density distribution in MgH2. X-ray powder diffraction data were obtained using the synchrotron radiation. The charge density distribution was calculated by the MEM (maximum entropy method)/Rietveld analysis. At room temperature, the charge density distribution around Mg is spherical, whereas the lower charge density distribution around H is non-spherical and slightly spread in the direction of the nearest neighbor Mg and H atoms. The number of electrons within the sphere around the Mg and the H atoms were estimated from the obtained distribution. As the result, Mg is almost fully ionized as Mg2+, whereas hydrogen is very weakly ionized. The ionic charge of hydrogen is lower than the theoretical value.

Original languageEnglish
Pages (from-to)84-86
Number of pages3
JournalJournal of Alloys and Compounds
Volume356-357
DOIs
Publication statusPublished - 2003 Aug 11
Externally publishedYes
EventProceedings of the Eight International Symposium on Metal Hyd (MH 2002) - Annecy, France
Duration: 2002 Sep 22002 Sep 6

Keywords

  • Charge density
  • Hydrogen storage materials
  • Magnesium hydride
  • Synchrotron radiation
  • X-ray diffraction

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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    Noritake, T., Towata, S., Aoki, M., Seno, Y., Hirose, Y., Nishibori, E., Takata, M., & Sakata, M. (2003). Charge density measurement in MgH2 by synchrotron X-ray diffraction. Journal of Alloys and Compounds, 356-357, 84-86. https://doi.org/10.1016/S0925-8388(03)00104-X