Biphenylene network: A nonbenzenoid carbon allotrope

Biphenylene carbon sheets Although graphene forms two-dimensional carbon sheets, other arrangements of carbon rings could also assemble as flat sheers. Fan et al. synthesized an ultraflat biphenylene carbon sheet consisting of sp 2 -hybridized carbon atoms forming four-, six-, and eight-membered rings on a gold surface. An adsorbed halogenated terphenyl molecule undergoes a two-step interpolymer dehydrofluorination polymerization that creates the four- and eight-membered rings through carbon–carbon bond formation. Scanning tunneling spectroscopy revealed that this carbon allotrope is metallic. Science , abg4509, this issue p. 852