A metallic carbon consisting of helical carbon triangle chains.
Carbon is the basis of life on Earth and many technological applications. We computationally report an sp3-hybridization-assembled carbon allotrope constructed by helical triangle chains through the evolutionary structure prediction method. Different from the previous metallic carbon K4, this carbon, called Tri-carbon, is mechanically and dynamically stable at ambient pressure. High ring strain in the carbon triangle blocks forces the C–C bond in Tri-carbon to be a 'bent bond', rather than the common single bond in diamond or the π bond in graphite. Unlike the unstrained sp3-hybridization in semiconductive diamond, valence electrons in the 'bent bond' are recombined to form extremely anisotropic sp3-hybridized bonds, thus conferring metallicity to Tri-carbon. Under nonhydrostatic conditions, Tri-carbon shows significantly anisotropic ideal tensile and compressive strength. Tri-carbon is expected to be achieved through chemical methods, such as the synthesis of cyclopropane derivatives (e.g. triangulane and tetrahedrane). These methods eliminate the restriction of ultra-high pressure to obtain metallic carbons.
Meng
M
Hu
Xiao
X
Dong
Yilong
Y
Pan
Bo
B
Xu
Dongli
D
Yu
Julong
J
He
D016880:Anisotropy; D003521:Cyclopropanes / Q000737:chemistry*; D018130:Diamond / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D012666:Semiconductors
D003521:Cyclopropanes; D008670:Metals; D018130:Diamond; D006108:Graphite