Chemistry of the Silicon‐Silicon Double Bond

Disilenes, compounds containing silicon‐silicon double bonds, can be isolated as thermally stable, yellow‐ or orange‐colored crystalline compounds; the substituent groups at silicon must be large (mesityl, tert ‐butyl, etc.) to prevent polymerization. Structural and spectro‐scopic studies indicate many similarities between the 3p–3p π bonding in disilenes and the 2p‐2p π bonding in olefins, but disilenes are much more reactive than alkenes. The reactions of disilenes lead to many new classes of silicon compounds, including three‐ and four‐membered rings which present novel problems in chemical bonding.