Silicon cyclopentadienides featuring a nonplanar 6π aromatic Si5 ring

Back to news list

Source: Science Magazine

Original: https://www.science.org/doi/abs/10.1126/science.aed0168?af=R...

Published: 2026-02-05T07:00:12Z

Chemists have created a stable five-membered silicon molecule (Si₅R₅⁻) that behaves similarly to the well-known carbon cyclopentadienide used in organometallic chemistry[1]. This molecule is essentially planar and exhibits aromatic properties, meaning that its electrons are distributed around the ring system in a manner that stabilizes it[1]. Although experimental and computational data indicate that the molecule rapidly oscillates between non-planar forms, its basic structure remains aromatic[1]. Researchers have confirmed that when a silicon molecule encounters a certain chemical (trimethylchlorostannane), its ring rearranges to a tricyclic form, confirming the important role of the lithium cation ion for the stability of the molecule[1]. This discovery is significant because all silicon aromatic molecules have long been the target of chemists since 1981 when stable silicon-silicon double bonds were first formed[1]. So far, only a three-membered silicon molecule of a similar type has been experimentally realized[1].