化学学报 ›› 2004, Vol. 62 ›› Issue (6): 556-560. 上一篇    下一篇

研究论文

亚汞氢氧化物Hg2(OH)2结构的理论研究

仇毅翔, 方华, 张勇, 王曙光   

  1. 上海交通大学化学化工学院, 上海, 200240
  • 投稿日期:2003-08-14 修回日期:2003-11-24 发布日期:2014-02-18
  • 通讯作者: 王曙光,E-mail:sgwang@sjtu.edu.cn E-mail:sgwang@sjtu.edu.cn

Theoretical Studies on the Structure of Hg(I)-hydroxidic Compounds

QIU Yi-Xiang, FANG Hua, ZHANG Yong, WANG Shu-Guang   

  1. School of Chemistry and Chemical Technology, Shanghai Jiaotong University, Shanghai 200240
  • Received:2003-08-14 Revised:2003-11-24 Published:2014-02-18

采用从头计算HF, MP2方法和密度泛函方法,选择LanL2DZ和SDD基组,对Hg2(OH)2的几何构型、振动频率和稳定性进行了研究,并与Hg2F2和Hg2Cl2的稳定性进行了对比.研究表明Hg的5s, 5p准内层电子参与了Hg与Hg之间的成键作用,Hg-Hg键强烈的电子相关作用使得HF方法不适用于该体系的研究.Becke的离域校正给出较大的Hg-Hg键长,而局域的DFT方法和MP2方法则给出了合理的结构参数、振动频率和能量.相对论效应使Hg-Hg键缩短24 pm,增加Hg-Hg键的强度达20%左右.Hg2(OH)2的稳定性与Hg2F2和Hg2Cl2的稳定性相当.虽然在气相中Hg2L2(L=F, Cl, OH)比其分解物HgL2和Hg要稳定,但相对论效应降低了这种趋势.

关键词: 亚汞离子, 从头计算, 密度泛函, 相对论效应

Geometries, vibrational frequencies and stability of Hg2(OH)2 as well as Hg2F2 and Hg2Cl2 have been investigated by means of ab initio HF, MP2 and density functional theory methods with LanL2DZ, SDD basis sets. The 5s, 5p semi-core of Hg has significant contribution to Hg—Hg bonding. HF method is not suitable for the [Hg—Hg]2+ system due to the strong correlation effects. The non-local exchange correction of Becke functional gives too long Hg—Hg distances. Local spin density functional theory and MP2 may reproduce the spectroscopic constants reasonably. Relativistic effects reduce the Hg—Hg bond lengths by about 24 pm and stabilize the Hg—Hg bond significantly by about 20%. Although Hg2L2 (L=OH, F, Cl) in disproportionation reaction Hg2L2→HgL+Hg is stable in the gas phase, relativistic effects reduce the tendency. The stability of Hg2(OH)2 is comparable to that of mercurous halides.

Key words: mercury(I)ion, ab initio, density functional theory, relativistic effect