在化学结构理论中,价键本性是一个极基本的问题。鲍林曾用共价键及离子键二种模型探讨各种有机分子的结构。在共振论中,鲍林认为共振结构式是一列价键桔构的杂成物。换言之,任何分子体系便是在这类价键结构之间共振。为了说明这种共振,鲍林还描绘了很多的价键结构式。实际上,这类价键结构是价电子的密度分布图,只有在一定条件下才有实际意义。如果外界环境改变,价电子的密度分布也有所改变,因此很难用图式准确说明。目前常用的古典结构式虽不能反映价电子云的分布情况,但可反映分子的 In the theory of chemical structure, the nature of the bond is a fundamental problem. Pauling once used two models of covalent bond and ionic bond to explore the structure of various organic molecules. In resonance theory, Pauling thought that the resonance structure is a series of miscellaneous matter with valence bond orange structure. In other words, any molecular system resonates between such valence bond structures. To illustrate this resonance, Pauling also portrayed a number of valence bond structures. In fact, such valence bond structure is the valence electron density distribution, which is of practical significance only under certain conditions. If the external environment changes, the density distribution of valence electrons has also changed, so it is difficult to use schematics to explain exactly. The commonly used classical structure can not reflect the distribution of valence electron cloud, but it can reflect the molecular