离子如何影响水的结构.
Barbara Hribar1, Noel T Southall, Vojko Vlachy
1Faculty of Chemistry and Chemical Technology, University of Ljubljana, Askerceva 5, 1000 Ljubljana, Slovenia.
Journal of the American Chemical Society
|October 10, 2002
概括
这项研究使用二维统计机械模型模拟水中的离子溶解. 它揭示了离子电荷密度和静电与结合之间的平衡决定了水的状况.
科学领域:
- 物理化学 物理化学
- 计算化学的计算化学
- 统计力学 统计力学
背景情况:
- 了解离子溶解对于各种化学和生物过程至关重要.
- 离子和水分子之间的复杂相互作用会影响溶液的特性.
- 现有的模型往往简化了水的结网和静电相互作用.
研究的目的:
- 开发和验证一种简化的离子-水相互作用模型.
- 研究水在离子和非极性溶液周围的结构组织.
- 阐明控制离子溶解和霍夫迈斯特效应的基本原则.
主要方法:
- 利用水的MB模型,一个2D统计机械模型.
- 在MB水分子中引入电荷双极.
- 进行了 (NPT) 蒙特卡洛模拟,以分析分子排列.
主要成果:
- 该模型准确地复制了粘度B系数,离子化能量和溶解热力学的实验数据.
- 证明了与霍夫迈斯特系列的Setschenow系数具有良好的定性一致性.
- 展示了离子电荷密度和静电和键的相互作用决定了水的结构.
结论:
- 离子电荷密度是离子与水相互作用的主要决定因素.
- 静电力和键之间的平衡决定了水对溶液的结构反应.
- 小,高电荷密度的离子 (宇宙物质) 强烈命令水,而大,低电荷密度的离子 (高质物质) 极小地破坏它.
相关概念视频
01:18Molecular Shapes
Molecules have characteristic shapes that are crucial for their function. The arrangement of various electron groups around the central atom dictates their molecular geometry. Electron pairs in the valence shell of a central atom will adopt an arrangement that minimizes repulsions between the electron pairs by maximizing the distance between them. The valence electrons form either bonding pairs, located primarily between bonded atoms, or lone pairs.Two regions of electron density in a diatomic...
01:29Covalent Bonds
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.A Covalent...
01:24Van der Waals Interactions
Atoms and molecules interact with each other through intermolecular forces. These electrostatic forces arise from attractive or repulsive interactions between particles with permanent, partial, or temporary charges. The intermolecular forces between neutral atoms and molecules are ion–dipole, dipole–dipole, and dispersion forces, collectively known as van der Waals forces.Polar molecules have a partial positive charge on one end and a partial negative charge on the other end of the molecule,...
03:13Intermolecular 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...
03:13Intermolecular 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...
01:08Covalent Bonds
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.
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.