層状のペロブスキート酸化水素の水素配列と新しいポリモルフ: Sr2VO4-x) H-x)
Joonho Bang1, Satoru Matsuishi, Haruhiro Hiraka
1Materials and Structures Laboratory, ‡Materials Research Center for Element Strategy, and ∥Frontier Research Center, Tokyo Institute of Technology , Yokohama 226-8503, Japan.
Journal of the American Chemical Society
|May 8, 2014
まとめ
調節可能なヴァナジウムオキシヒドリドSr2VO ((4-x) H ((x)) が合成され,水素が結晶構造で酸素を代用することを示した. この置換は,新しい秩序化された相につながり,バナジウム-リガンド結合相互作用に影響を与えます.
科学分野:
- 材料科学 材料科学とは
- 固体化学 固体化学
- 無機化学 無機化学とは
背景:
- バナジウム酸化水素は,調節可能な電子および磁気特性を有する材料のクラスです.
- アニオン組成と順序を制御することは,それらの性能を理解し,最適化するために不可欠です.
- 以前の合成方法では,多くの場合,アニオン空白が大きくなり,特性分析が複雑になりました.
研究 の 目的:
- 構成的に調節可能なバナジウムオキシヒドリドSr2VO(4-x) H(x) を最小限のアニオン空白で合成する.
- 水素含有量の関数としてこれらの材料の構造的進化とアニオン順序を調査する.
- アニオン配列と電子構造,特にバナジウム-リガンド結合の関係を解明する.
主な方法:
- 合成のための高圧固体反応.
- 粉末中性子 difraktionとシンクロトロンX線 difraktionで結晶構造を決定する.
- 組成分析のための熱分解スペクトロスコピー.
- 第一原理 電子構造と結合分析のための密度関数理論 (DFT) 計算.
主要な成果:
- Sr2VO ((4-x) H ((x) (0 ≤ x ≤ 1.01) の合成が成功し,水素の組み込みが制御され,酸素の空白が最小限に抑えられた.
- VO6層における,特に低水素含有量 (x < 0.2) の場合における,赤道酸素の水素アニオンによる選択的置換の観測.
- 高い水素含有量 (x > 0.7) の有序な水素アニオンによる新しいオーソロンビック (Immm) 段階の形成,最初の四角形 (K2NiF4型) 段階から移行する.
- DFTの計算は,酸素/水素アニオン配列の度合いとバナジウム-リガンド結合相互作用の間の強い相関を明らかにした.
結論:
- 構成的に調節可能なバナジウム酸化水素は,高圧方法によって合成され,水素含有量を正確に制御することができます.
- 水素の組み込みは,異なる構造的相変異とアニオン順序化現象をもたらします.
- 観測されたアニオン順序は電子特性に大きく影響し,機能的な材料の設計における構造制御の重要性を強調しています.
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