高等学校化学学报 ›› 2012, Vol. 33 ›› Issue (07): 1505-1510.doi: 10.3969/j.issn.0251-0790.2012.07.026

• 物理化学 • 上一篇    下一篇

金属离子Na+ , Li+ , Mg2+与硫酸根离子形成的无水缔合物种的从头算量子化学研究

万素琴1, 张一2, 张浩1, 孙家锺1   

  1. 1. 吉林大学理论化学研究所, 理论化学计算国家重点实验室, 长春 130021;
    2. 辽宁工程技术大学化工研究院, 葫芦岛 125000
  • 收稿日期:2012-02-07 出版日期:2012-07-10 发布日期:2012-07-10
  • 通讯作者: 张 浩, 男, 博士, 副教授, 主要从事理论化学基础理论及应用研究. E-mail: stringbell@jlu.edu.cn E-mail:stringbell@mail.jlu.edu.cn
  • 基金资助:

    吉林省自然科学基金(批准号: 20101552)和吉林大学自主研究课题项目(批准号: 450060481346)资助.

Ab initio Investigation on Unhydrated Ion-associated Species Between Na+, Li+, Mg2+ and SO42- Ions

WAN Su-Qin1, ZHANG Yi2, ZHANG Hao1, SUN Chia-Chung1   

  1. 1. State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130021, China;
    2. Research Institute of Chemical Industry, Liaoning Technical University, Huludao 125000, China
  • Received:2012-02-07 Online:2012-07-10 Published:2012-07-10

摘要: 计算并讨论了Na+, Li+和Mg2+ 3种离子与SO42-离子形成离子缔合物的结构以及阳离子的结合对ν1-SO42-频率的影响. 结果表明, 在缔合物结构方面, 阳离子数目越少, 离子间斥力越小, 越容易形成阳离子与硫酸根间距离更短, 结合更紧密的双齿缔合结构; 而当阳离子数目增加时, 特别是当具有2个正电荷的Mg2+离子数目较多时, 离子间的斥力使多离子团簇不稳定, 易形成阳离子与硫酸根间距离更长的单齿缔合结构. 有2种阳离子作用可影响ν1-SO42-频率, 一种是极化作用, 可使ν1-SO42-频率红移; 另一种是成键作用, 可使ν1-SO42-频率蓝移. 当金属离子数目≤2时, 阳离子的极化作用占主导地位, 第一个阳离子能使ν1-SO42-频率发生红移, 而当阳离子数目增多时, 不同方向结合的其它阳离子可以削弱第一个阳离子的极化作用, 因此导致多离子团簇中ν1-SO42-频率红移的减小. 当阳离子数目≥3时, 极化作用影响减小, 成键作用占据主导地位, 导致ν1-SO42-频率更大蓝移的单齿缔合结构取代双齿结构, 并使多离子团簇中的ν1-SO42-频率继续发生蓝移.

关键词: 量子化学计算, 硫酸盐, 离子缔合物种, ν1-SO42-频率

Abstract: The structures of ion-associated species between Na+, Li+, Mg2+ and SO42- ions were optimized via ab initio calculations. And the influences of the cations to the ν1-SO42- frequencies were also investigated. For the ion-associated structures, when there are fewer cations, the repulsion between cations will decrease and thus the bidentate associated structures are easy to form, in which there is shorter distance between metal ion and SO42-. Contrarily, comparing with the increase of the number of cations in the ion clusters, especially for more Mg2+ ions which have more positive charge, the repulsions between metal ions would make the clusters instable and more monodentate structures are formed, in which the distances between metal and SO42- ions are longer. The metal ions could influence the ν1-SO42- frequencies via two ways. The first one is polarization of the cation, which leads the ν1-SO42- frequency red-shift, while another one is M-O bonding action, which lead the opposite blue-shift. When the number of metal ions ≤2, the first one is dominated. The first metal ion can lead the ν1-SO42- frequency red-shift, while more metal ions from different directions would decrease the red-shift. When the number of metal ions >2, the M-O bonding action is the main interaction manner. The increase of the monodentate associated structures in the quadruple or quintuple ion clusters, which can lead the more blue-shift than those of the bidentate ones, will make the ν1-SO42- frequency more blue-shift than those in the triple ion clusters.

Key words: Quantum chemistry calculation, Sulfate, Ion-associated species, ν1-SO42- frequency

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