関連する実験動画
Updated: Mar 22, 2026
06:44
Tuning Oxide Properties by Oxygen Vacancy Control During Growth and Annealing
Published on: June 9, 2023
4.0K
A2BO4スピネル酸化物におけるカチオン順序の普遍的静電起源
Vladan Stevanović1, Mayeul d'Avezac, Alex Zunger
1National Renewable Energy Laboratory, Golden, Colorado 80401, USA. vladan.stevanovic@nrel.gov
Journal of the American Chemical Society
|June 28, 2011
まとめ
単純な静電モデルにより,A(2) BO(4) のスピネル酸化物におけるカチオン順序が説明されます. このモデルは,オーダー・ディオードー・トランジションの特徴的な温度を予測し,カチオン電荷と相関し,3−2および2−4スピネルの観測されたディオードーレベルを説明します.
科学分野:
- 固体化学 固体化学
- マテリアルサイエンス 材料科学
- クリスタルグラフィーです.
背景:
- A(2) BO(4) スピネル酸化物は,カチオン分布に基づいて正常または逆の結晶構造を示す.
- これらの構造は,温度に依存する秩序と混乱の現象を経験します.
研究 の 目的:
- シンプルなポイントイオン静電 (PIE) モデルが,A(2) BO(4) スピネルにおける普遍的な構造変化を自然に説明できることを示す.
- PIEモデルを使用して,秩序-乱雑の移行温度を定量的に予測する.
- これらの移行温度の大小とカチオン電荷を相関させるため.
主な方法:
- ポイントイオン静電 (PIE) モデルの開発と応用.
- PIEハミルトニアンのモンテカルロシミュレーションを用いて.
- 気温の関数として,カチオン分布と秩序乱象現象を分析する.
主要な成果:
- 単一のパラメータを持つPIEモデルは,A(2) BO(4) スピネルの特徴的な構造変化を成功裏に再現します.
- モンテカルロシミュレーションは,定量的な秩序-乱乱特有の温度を提供します.
- 陽子電荷と移行温度との間には直接的な相関が確立され,3−2と2−4のスピネルクラス間の違いが説明されます.
結論:
- PIEモデルは,スピネルのカチオン順序を理解するための基本的な枠組みを提供します.
- 特徴的な秩序-乱気温は,原子電荷に基づいて予測可能である.
- このモデルは,2〜4のスピネルと比較して,3〜2のスピネルで観察されたより高いレベルの障害を説明しています.
さらに関連する動画
関連する概念動画
02:42Valence Bond Theory
11.6K
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...
11.6K
02:58Crystal Field Theory - Octahedral Complexes
31.6K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
31.6K
03:02Colors and Magnetism
14.5K
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...
14.5K
02:42Ionic Crystal Structures
20.2K
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...
20.2K
02:48Ionic Bonding and Electron Transfer
53.7K
Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence shell, and an anion (a negative ion) forms when a neutral atom gains one or more electrons in its valence shell. Compounds composed of ions are called ionic compounds (or salts), and their constituent ions are held together by ionic bonds: electrostatic forces of attraction between oppositely charged cations and anions.
53.7K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
49.5K
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,...
49.5K