在含有三价金属离子的水集群中,电子水合和离子-电子对
William A Donald1, Maria Demireva, Ryan D Leib
1Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Journal of the American Chemical Society
|March 12, 2010
概括
研究人员研究了水合电子,这是一个基本的水性核友. 他们通过使用稳定的电子溶解三价 lanthanide 离子水集群来确定其散装水解为 -1.3 eV.
科学领域:
- 物理化学 物理化学
- 化学物理 化学物理
- 材料科学 材料科学 材料科学
背景情况:
- 水合电子是水溶液中的关键核友,但其在液态水中的短暂性质给研究带来了重大挑战.
- 了解电子溶解热力学对于描述电子带结构和水和水系统的特性至关重要.
- 之前的研究得出了广泛的电子溶解值 (-1.0至-1.8 eV),这是由于质子溶解的不确定性.
研究的目的:
- 准确地确定电子在水溶液中的散装水化热量.
- 为了研究电子与水分子在稳定,气相集群中的相互作用.
- 建立一种可靠的方法来计算电子水合度,而不依赖于质子溶解值.
主要方法:
- 产生含有多余电子和溶剂分离的三价金属离子的稳定水集群 (兰坦化集群).
- 根据电子捕获时的水分子损失,测量了La(H2O) n3+ (n = 42160) 的亚亚巴特重组能.
- 将再组合度推算到无限集群大小,以确定散装水化度,考虑大小依赖的几何因素.
主要成果:
- 随着集群大小的增加,观察到电子定位的结构性过渡,从表面结合 (n ≤ ~ 56) 到完全溶解 (n ≥ ~ 60).
- 获得了水合兰化集群在一系列水合数的亚亚巴特重组能.
- 通过对集群数据进行推断,确定电子的散装水合度为-1.3 eV.
结论:
- 该研究成功地确定了电子的散装水化度,使用从气相集群数据的新型抽取方法.
- 这些发现为电子溶解度提供了更准确的值,解决了以前的模两可.
- 这种方法提供了一个优势,因为它规避了对绝对质子或液化热量估计的需求.
相关概念视频
02:54Ions as Acids and Bases
Salts with Acidic Ions
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
02:51Metal-Ligand Bonds
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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...
02:48Ionic Bonding and Electron Transfer
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.
02:42Aqueous Solutions and Heats of Hydration
Water and other polar molecules are attracted to ions. The electrostatic attraction between an ion and a molecule with a dipole is called an ion-dipole attraction. These attractions play an important role in the dissolution of ionic compounds in water.
When ionic compounds dissolve in water, the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them. This process...
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03:45Formation of Complex Ions
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01:19Complexation Equilibria: The Chelate Effect
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