非经典多重键

Nonclassical Multiple Bonds

在难以形成经典多重键的重原子 (第三周期以下 )之间可以形成一种非经典多重键。由于构成双键的两部分 (即两个分子片 )的基态分别是单线态 ,这种电子结构导致非经典双键由两个配位键构成 ,非经典三键则是在此基础上再加上一个π键。这种多重键的强度和键级较经典多重键为低。与两个配位键的电子结构相对应 。

Nonclassical multiple bonds exist between the heavy atoms, such as Si, Ge, Sn, etc.. The nonclassical double bond consists of two dative bonds, and the nonclassical triple bond has additional π bond. The nonclassical multiple bonds have less bond strength and smaller bond order than the classical multiple bonds. Consequently, the trans-bent geometry is required for the molecule with the nonclassical multiple bond in order to match its electronic structure.