The structures of B_2n(CO)_n (n＝1～6) compounds were studied by B3LYP with basis set of B3LYP/6-31G*. By discussing the geometries, electron structures, vibrational frequencies, nucleus independent chemical shifts (NICS) of the most stable structures and B₂CO molecule orbital, we got the stable information of B_2n(CO)_n (n＝1～6) compounds. Among all of the ground states structures, the ground states of B_2n(CO)_n (n＝1～5) are linear or planar, B₁₂(CO)₆ is appreciably intricate, and the carbonyls of ground state B_2n(CO)_n (n＝1～6) are μ₁-CO. The ground state structures of B_2n(CO)_n (n＝1～3) are triplet, and the ground state structures of B_2n(CO)_n (n＝4～6) are singlet. The analyses of the vibrational spectra and molecule orbital provide some important direction on the experiment.

Key words: carbonyl boron compound, density functional theory (DFT), structure and stability