Ca2MnO3X (X = Cl, Br) 平方平面 S = 2 Mn3 の1次元の鉄磁気鎖を持つオキシハリド
Fabio Denis Romero1, Christophe Lepoittevin1, Stéphanie Kodjikian1
1Univ. Grenoble Alpes, CNRS, Grenoble INP, Institut Néel, 38000 Grenoble, France.
Journal of the American Chemical Society
|October 13, 2023
まとめ
新しい混合アニオンオキシハリド,Ca2MnO3X (X=Cl,Br) は,新しい結晶構造とユニークな磁性特性を表しています. これらの材料は,磁場下でスピンフロップの移行を伴う結合された鉄磁気および反鉄磁気配列を示しています.
科学分野:
- 固体化学
- 材料科学
- マグネティズム
背景:
- 混合アニオンオキシハリドは新興の機能材料のクラスです.
- カルシウム・マンガン・オキシハリド (Ca2MnO3X) は,新しい構造的および磁性特性を提示する.
- 小さなイオン半径とヤーン・テラー効果の相互作用が結晶構造に影響する.
研究 の 目的:
- 新しい混合アニオンオキシハリドCa2MnO3X (X = Cl, Br) を合成し,特徴づけること.
- これらの化合物の結晶構造と磁気性を調べる
- 構造と磁気配列の関係を理解する
主な方法:
- 固体反応合成について
- 構造の決定のためのX線結晶学.
- 探査機の磁気配合に対する磁気感受性測定
主要な成果:
- Ca2MnO3X (X = Cl, Br) が成功して合成されました.
- 新しい結晶構造 (空間群Cmcm) が特定され,MnO4四角平面の1D鎖を特徴とした.
- 低温で鉄磁気鎖の反鉄磁気結合が観察された.
- Spin-flopのトランジションは磁場を適用して誘導された.
結論:
- Ca2MnO3X (X = Cl, Br) の合成により,混合アニオンオキシハリドのファミリーが拡大する.
- 新しい構造はCa2+イオン半径とMn3+ヤーン-テラー効果に起因する.
- これらの材料は複雑な磁気順序と磁場誘発の移行を示し,磁気応用の可能性を強調しています.
関連する概念動画
02:42Valence Bond Theory
8.6K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.6K
03:02Colors and Magnetism
11.8K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
11.8K
02:42Ionic Crystal Structures
14.4K
Ionic crystals consist of two or more different kinds of ions that usually have different sizes. The packing of these ions into a crystal structure is more complex than the packing of metal atoms that are the same size.
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
Most monatomic ions behave as charged spheres, and their attraction for ions of opposite charge is the same in every direction. Consequently, stable structures for ionic compounds result (1) when ions of one charge are surrounded by as many ions as possible of the opposite...
14.4K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
42.7K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
42.7K
02:57Coordination Number and Geometry
15.9K
For transition metal complexes, the coordination number determines the geometry around the central metal ion. Table 1 compares coordination numbers to molecular geometry. The most common structures of the complexes in coordination compounds are octahedral, tetrahedral, and square planar.
15.9K
01:31Ferromagnetism
2.4K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.4K