封闭外的分子比更容易电离.
F Albert Cotton1, Nadine E Gruhn, Jiande Gu
1Department of Chemistry and Laboratory for Molecular Structure and Bonding, Texas A&M University, Post Office Box 30012, College Station, TX 77842-3012, USA. cotton@tamu.edu
Science (New York, N.Y.)
|December 10, 2002
概括
研究人员发现了具有非常低的电离能量的新二金属复合物,甚至超过了. 这些新型分子M2 (hpp) 4为化学键和电子行为提供了突破性的见解.
科学领域:
- 无机化学 无机化学
- 物理化学 物理化学
- 量子化学 是一个量子化学.
背景情况:
- 中性原子或分子的电离能是与其电子结构相关的基本性质.
- 在所有已知的元素中,是最低的电离能量的记录.
- 发现离子能低于的物种是一个重大的科学挑战.
研究的目的:
- 报告一种新型的二金属复合物的类别,具有异常低的离子化度.
- 为了研究这些低电离能量的电子结构和粘合特性.
- 将这些复合物的电离性质与已知的元素和分子进行比较.
主要方法:
- 合成和结构特征的M2 (hpp) 4复合体 (M = Cr,Mo,W).
- 气相光谱表征以确定电离能.
- 理论计算以建模电子结构和结合.
主要成果:
- 合成了一种新型的二金属复合物,M2(hpp) 4,表现出极低的电离度.
- 一个复合体的气相电离能为3.51 eV,低于和所有其他报道的封闭外分子.
- 电离涉及从四重金属-金属键内的三角键轨道中去除电子,受到hpp连接体的强烈影响.
结论:
- 发现的二金属复合体代表了低电离能物种的新前沿.
- 独特的电子配置,特别是与hpp配体的三角结合轨道相互作用,决定了非常低的电离能.
- 这些发现为探索具有定制电子特性的新材料开辟了道路.
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Overview
When two atoms share electrons to complete their valence shells, they create a covalent bond. An atom's electronegativity—the force with which shared electrons are pulled towards an atom—determines how the electrons are shared. Molecules formed with covalent bonds can be either polar or nonpolar. Atoms with similar electronegativities form nonpolar covalent bonds; the electrons are shared equally. Atoms with different electronegativities share electrons unequally, creating polar bonds.
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