The geometrical structures, growth modes, and relative stabilities of boron-carbon clusters B_nC₂ (n＝1～6) have been investigated by performing density functional theory calculations at B3LYP/6-311＋G(d) level. The calculated results show that the planar multi-cyclic geometries for n＝2～6 with C atoms at the apexes with the most B—C bonds and the most three-coordination boron atoms are the most stable structures. It is also shown that the C atoms prefer the apexes of the rings, which does not change the frame structures of the B clusters. The compact 3D structures and the linear isomers, however, are energetically more unfavorable with the increasing size. In the energetically lowest linear isomers, the carbon atoms prefer the second positions of the chains. The cal-culated disproportionation energies, binding energies and HOMO-LUMO gaps show that the B₄C₂ is a magic cluster.

Key words: boron-carbon cluster, doping, geometric structure, stability, density functional theory