Structural, energetic, and magnetic criteria confirm that the silole d
ianion (CHSi2- (7) and its alkali-metal ion pairs, e.g. (CH)(4)SiLi- (
7a), (CH)(4)SiLi2 (7b), (CH)(4)SiNa2 (13), and (CH)(4)SiK2 (14), are h
ighly aromatic. Inverse sandwich structures and strongly delocalized s
ilole rings are prefered by 7b, 13, and 14. The degree of aromaticity
in. [eta(5)-(CH)(4)Si]Li- (7a) exceeds that of the isoelectronic third
-period heterocycles (CH)(4)-PLi (5a) and (CH)(4)SLi+ (6a) and even ap
proaches that of (CH)(5)Li (3a).