Crystal structure and local structure of Mg2-xPr xNi4 (x = 0.6 and 1.0) deuteride using in situ neutron total scattering

K. Sakaki, N. Terashita, H. Kim, T. Proffen, E. H. Majzoub, S. Tsunokake, Y. Nakamura, E. Akiba

研究成果: Contribution to journalArticle査読

19 被引用数 (Scopus)

抄録

We studied crystal structure and local structure of Mg2-xPr xNi4 (x = 0.6 and 1.0) and their deuterides using in situ neutron total scattering and first-principles calculations. The total scattering data were analyzed using Rietveld refinement and pair distribution function analysis (PDF). The crystal structure of Mg2-xPrxNi 4 before deuterium absorption was C15b in space group F4̄3m. No difference between the crystal and local (PDF) structures was observed. The crystal structure of Mg1.0Pr1.0Ni4D ∼4 was found to be orthorhombic in space group Pmn21, with three deuterium occupation sites: PrNi3 and two types of bipyramidal Pr2MgNi2 that have a plane of symmetry composed of MgNi2. There is no significant difference between the crystal structure and the local structure of Mg1.0Pr 1.0Ni4D∼4. On the other hand, the average crystal structure of the Mg-rich Mg1.4Pr0.6Ni 4D∼3.6 was C15b with two deuterium occupation sites: PrNi3 and MgPrNi2 suggesting that the deuterium occupation shifts away from the Pr2MgNi2 bipyramid. First-principles relaxed structures also showed the shift of the hydrogen occupation site toward the Pr atom of the bipyramid, when induced by Mg substitution for the opposing Pr, resulting in hydrogen occupation in the MgPrNi2 tetrahedral site. The PDF pattern of Mg1.4Pr0.6Ni4D ∼3.6 cannot be refined below 7.2 Å in atomic distances using the C15b structure which was obtained from Rietveld refinement but can be done using an orthorhombic structure. It suggests that Mg1.4Pr 0.6Ni4D∼3.6 was locally distorted to the orthorhombic.

本文言語英語
ページ(範囲)7010-7019
ページ数10
ジャーナルInorganic chemistry
52
12
DOI
出版ステータス出版済み - 6 17 2013

All Science Journal Classification (ASJC) codes

  • 物理化学および理論化学
  • 無機化学

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「Crystal structure and local structure of Mg<sub>2-x</sub>Pr <sub>x</sub>Ni<sub>4</sub> (x = 0.6 and 1.0) deuteride using in situ neutron total scattering」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

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