Linear, planar, and tubular molecular structures constructed by double planar tetracoordinate carbon D 2 h C 2 (BeH) 4 species via hydrogen‐bridged BeH 2 Be bonds

This computational study identifies the rhombic D 2 h C 2 (BeH) 4 ( 2a ) to be a species featuring double planar tetracoordinate carbons (ptCs). Aromaticity and the peripheral BeBeBeBe bonding around CC core contribute to the stabilization of the ptC structure. Although the ptC structure is not a global minimum, its high kinetic stability and its distinct feature of having a bonded C 2 core from having two separated carbon atoms in the global minimum and other low‐lying minima could make the ptC structure to be preferred if the carbon source is dominated by C 2 species. The electron deficiency of the BeH group allows the ptC species to serve as building blocks to construct large/nanostructures, such as linear chains, planar sheets, and tubes, via intermolecular hydrogen‐bridged bonds (HBBs). Formation of one HBB bond releases more than 30.0 kcal/mol of energy, implying the highly exothermic formation processes and the possibility to synthesize these nano‐size structures. © 2015 Wiley Periodicals, Inc.