物理化学学报 >> 2007, Vol. 23 >> Issue (05): 786-789.doi: 10.3866/PKU.WHXB20070532

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导出铅(II)—卤素键价参数的一条新途径

胡盛志   

  1. 厦门大学化学系, 物理化学研究所, 福建 厦门 361005
  • 收稿日期:2006-12-07 修回日期:2007-03-02 发布日期:2007-04-28
  • 通讯作者: 胡盛志 E-mail:szhu@xmu.edu.cn

A New Approach to Bond Valence Parameters for Pb(II)—halide Bonds

HU Sheng-Zhi   

  1. Institute of Physical Chemistry, Department of Chemistry, Xiamen University, Xiamen 361005, Fujian Province, P. R. China
  • Received:2006-12-07 Revised:2007-03-02 Published:2007-04-28
  • Contact: HU Sheng-Zhi E-mail:szhu@xmu.edu.cn

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摘要： 基于精确的晶体结构数据并设定B=0.037 nm 以拟合经验参数R0是通常采用的键价参数推导方法. 与此相反, 作者提出从分子气相电子衍射的键长设定经验参数R0, 然后从晶体结构数据拟合经验参数B. 以Pb(II)—卤素键为例, PbX2气相电子衍射Pb—X(X=F, Cl, Br, I)键长分别为0.2036, 0.2447, 0.2598 和0.2804 nm, 经拟合到最佳B值分别为0.0382, 0.040, 0.040, 0.0386 nm, 与普适参数B值0.037 nm 有一定的差距. 所提出的键价参不仅得到比较理想的键价值和计算结果, 而且保留了键价参数R0作为单价键长明确的物理意义.

关键词: 键价参数, 单价键长, 电子衍射, 铅(II)卤化物

Abstract:

The values of bond valence parameters R0 for the bonds of main group metal halides are usually obtained by systematic analysis of the crystal structure data by assuming B=0.037 nm. In this work, conversely, the values of B were proposed to be fitted with crystal structure data on assuming the values of R0 equal to the bond lengths of rg accurately determined by gaseous electron diffraction. As an example, the new sets of R0 /B for the Pb(II)—X (X=F, Cl, Br, I) bonds were obtained and fitted as 0.2036/0.0382, 0.2447/0.040, 0.2598/0.040, and 0.2804/0.0386, respectively. Compared with the values of R0=0.203, 0.253, 0.264, and 0.278 nm based on B=0.037nm for Pb(II)—X bonds reported in the literature, these new parameters were not only accurate and reliable for bond valence calculations, but also revealed the physical meaning inherent in every R0 as unit valence bond length.

Key words: Bond valence parameter, Bond length of unit valence, Electron diffraction, Pb(II) dihalide