Structures and Properties of CoB₁₉ ^+/0/- Clusters

A global search for the lowest energy structure of Co atom-doped boron clusters (CoB₁₉ ⁺, CoB₁₉, and CoB₁₉ ^- clusters) was conducted. The lowest energy structures of them are remarkably different from those of B₂₀ and CoB₁₈ ^- clusters. CoB₁₉ ⁺ clusters have a bowl-shaped geometry, where the Co atom is at the bottom of the bowl and is coordinated with eight B atoms. The CoB₁₉ cluster presents seven- and eight-membered B rings. The CoB₁₉ ^- cluster can be viewed as a structure that evolves from a Co-doped boron plane. The coordination number of CoB₁₉ and CoB₁₉ ^- clusters are 16 and 14, respectively. Several low-lying isomers have quasi-planar structures for the CoB₁₉ ^- cluster. Some properties including charge transformation and distribution, HOMO-LUMO gaps, molecular orbital distribution, and stability of neutral CoB₁₉ are discussed. CoB₁₉ ⁺ and CoB₁₉ ^- exhibit magnetism with a net moment of 1.0 and 0.94 μ_B because of odd number of electrons.