Structure and bonding of new boron and carbon superpolyhedra

Using the DFT methods, we computationally predict the stability of cage compounds E4nRn (E = B, C; R = H, F; n=4, 8, 12, 24) based on Platonic bodies and Archimedean polyhedrons in which all vertices are replaced by tetrahedral E4R fragments. Cage compounds B60R12 and C-60 with pyramidal units B5R or C-5 are also examined and it is shown that only boron compounds are stable. The nature of chemical bonding in the discussed compounds is analyzed using the AdNDP and NBO methods. The hydrocarbons have classical 2c-2e C-C sigma-bonds, while the boron compounds are formed by the polyhedral units with the delocalized multicenter bonds which connected three and more boron atoms. The new example of spherical aromaticity according to the 2(N+1)(2) rule in the case of B16F4 with multicenter 16c-2e bonds are revealed. Stable compound B60H12 contains 12 5c-2e B-B bonds.