Because of the electron deficiency for boron,bulk boron and metal borides possess unusual chemical bonding and physicochemical properties,and have attracted sustained research interests over the past decades.Metal boride clusters can be used as models to provide fundamental insights into molecular structures and chemical bonding.In the current work,we are interested in investigating the structural and electronic properties of di-niobium boride clusters Nb2Bx-/0(x = 1-6).Extensive DFT calculations were performed at the BP86 level to locate the ground states of Nb2Bx-/0(x = 1-6).The fascinated structural evolution is observed in Nb2Bx-(x = 1-6)clusters,which shows the equatorial boron chain extends around the Nb-Nb dimer with x increasing and an enclosed planar B6 ring emerges in Nb2B6-species.The ground state of Nb2B6-cluster(Figure 1a)is found to be a hexagonal bipyramid structure with D6h(2A2u)symmetry.The ground state of Nb2B6(D6h,1A1g)(Figure 1b)is similar to the anion in term of atomic connectivity.Vertical electron detachment energies(VDEs)are calculated using the generalized Koopmans theorem.The first VDE(Figure 1c)of Nb2B6-is calculated to be 1.31 eV.Molecular orbitals are performed to elucidate the chemical bonding and electronic properties in these clusters.