多核金属离子复合体在固体/水界面上的证据来自X射线吸收光谱学X射线吸收光谱
C J Chisholm-Brause1, P A O'Day, G E Brown
1Aqueous and Surface Geochemistry Group, School of Earth Sciences, Stanford University, California 94305-2115.
Nature
|December 6, 1990
概括
在X射线吸收光谱检测中,矿物表面上发现了多核复合体. 不同的矿物类型改变了表面复杂结构,影响了金属离子吸附模型.
科学领域:
- 环境化学环境化学
- 地质化学 地质化学
- 材料科学 材料科学 材料科学
背景情况:
- 自然水中的金属吸收到矿物质上,影响它们的行为和运输.
- 了解固体/水界面化学对于预测金属的行为至关重要.
- 射线吸收光谱 (XAS) 识别了复杂的表面结构和结合.
研究的目的:
- 为了研究二价 (Co(II)) 复合物的结构,在玛-Al2O3,鲁 (TiO2) 和高酸盐上吸收.
- 确定不同矿物表面对金属吸附复合体形成的影响.
- 为准确的金属离子吸附建模提供洞察力.
主要方法:
- 使用X射线吸收光谱法 (XAS).
- 双价 (Co(II)) 吸附在玛-Al2O3,鲁 (TiO2) 和高上进行了研究.
- 分析了近邻原子,原子间距离和复杂结构的光谱数据.
主要成果:
- 在单层覆盖范围以下发现了多核C02吸附复合物的直接证据.
- 在三种固体上观察到Co (II) 的协调原子和原子间距离的明显差异.
- 表面复杂的结构根据矿物基质的基础上有显著的变化.
结论:
- 矿物表面,包括氧化物和粘土,影响水性表面复合物的结构.
- 这些发现凸显了金属吸附中表面特异相互作用的重要性.
- 准确的金属离子吸附模型必须考虑到矿物表面的特性.
相关概念视频
Intermolecular Forces
Atoms and molecules interact through bonds (or forces): intramolecular and intermolecular. The forces are electrostatic as they arise from interactions (attractive or repulsive) between charged species (permanent, partial, or temporary charges) and exist with varying strengths between ions, polar, nonpolar, and neutral molecules. The different types of intermolecular forces are ion–dipole, dipole–dipole, hydrogen bonds, and dispersion; among these, dipole–dipole, hydrogen bonds, and dispersion...
Formation of Complex Ions
A type of Lewis acid-base chemistry involves the formation of a complex ion (or a coordination complex) comprising a central atom, typically a transition metal cation, surrounded by ions or molecules called ligands. These ligands can be neutral molecules like H2O or NH3, or ions such as CN− or OH−. Often, the ligands act as Lewis bases, donating a pair of electrons to the central atom. These types of Lewis acid-base reactions are examples of a broad subdiscipline called coordination...
Metal-Ligand Bonds
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
Crystal Field Theory - Octahedral Complexes
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...
Complexation Equilibria: Factors Influencing Stability of Complexes
In complexation reactions, metal cations are the electron pair acceptors, and the ligands are the electron pair donors. The stability of the metal complexes depends primarily on the complexing ability of the central metal ion and the nature of the ligands. Generally, the complexing ability of the metal ion depends on the size and charge of the ion. As the metal ion size increases, the stability of the metal complexes decreases, provided that the valency of the metal ion and the ligands remain...
Complexometric Titration: Ligands
Different monodentate and polydentate ligands are used as complexing agents in complexometric titration reactions. The formation of complexes by mono- and bidentate ligands involves two or more intermediate steps, limiting their use as complexing agents. In comparison, polydentate ligands can form complexes with metal ions in a single-step process, facilitating sharper end points. This means polydentate ligands, such as amino carboxylic acid derivatives, are most commonly employed in...


