A review of linear carbon chains

Linear carbon chains(LCCs)are a one-dimensional sp1-hybridized allo trope of ca rbon.LCCs are extre mely unstable:The longer the LCCs,the less stable the materials.Thus,it is a big challenge to synthesize long LCCs.Although the research on the short LCCs,e.g.,polyynes,can be traced back to the 18th,LCCs are still not well-known compared to other allotropes of carbon,e.g.,fullerenes,carbon nanotubes and graphene.Therefore,introducing recent progress on LCCs is of great significance to draw more attention in the community of nanocarbons as well as nanomaterials in general.Theoretically,various excellent properties have been predicted.Experimentally,LCCs with different length in many kinds of forms have been successfully synthesized.In this review,we summarized recent studies of polyynic LCCs from both theoretical and experimental aspects.Also,perspectives are highlighted to point out the further investigations of the materials.