Systematic Enumeration of sp3 Nanothreads

摘要: Slow decompression of crystalline benzene in large-volume high-pressure cells has recently achieved synthesis a novel one-dimensional allotrope sp3 carbon which stacked columns molecules rehybridize into an ordered crystal nanothreads. The progenitor function as six-valent superatoms with multiple binding sites. Here we enumerate their hexavalent bonding geometries, recognizing that the repeat unit interatomic connectivity (“topological cell”) need not coincide crystallographic cell, and identify most energetically favorable cases. A topological cell one or two rings at least bonds interconnecting each adjacent pair rings, accommodates 50 topologically distinct nanothreads, 15 are within 80 meV/carbon atom stable member. Optimization aperiodic helicity reveals structures to be chiral. We generalize Euler’s rules for ring counting cover this new form v...