Theoretical study of the electronic and molecular structures of boron and carbon penta-hepta-membered ring networks and ScBC clusters

The present work reports the ab initio results of the electronic and molecular structures of the B and C penta-hepta- (5-7) membered ring (BC 5-7MR) network and ScBC clusters. The planarity of the BC 5-7MR network stage is realized when the empty π-bonding orbitals are fully filled by electrons. However, the interelectronic repulsion resulting from the simple electron injection destabilizes the BC stage energetically. The intercalated Sc atoms of the ScBC layered compound play an important electronic role in providing the planarity of the BC stage through the orbital mixings. The corresponding π-d and π-s hybridizations stabilize the p orbitals energetically and cause an electron transfer from the Sc atoms into the BC stage. The donated electrons fully fill the empty but stabilized p orbitals so as to maintain the planarity of the BC stage.