Anion photoelectron spectroscopy and density functional investigation of diniobium-carbon clusters.

Experimental photoelectron and computational results show diniobium−carbon (Nb2Cn) clusters to coexist in multiple structural isomers: three-dimensional geometries, planar rings, and linear chains. Three-dimensional clusters having up to five carbons are formed preferentially with Nb−Nb bonding, whereas only Nb−C bonding is observed experimentally at six carbons. Clusters consisting of an odd number of atoms are also observed with linear geometries. The larger binary clusters (n ≥ 7) display properties similar to those of pure carbon clusters. We provide evidence for niobium substitution of carbon atoms.