The exploration of metal-doped boron clusters has a great significance in the design of high coordination number (CN) compounds. Actinide-doped boron clusters are probable candidates for achieving high CNs. In this work, we systematically explored a series of actinide metal atom (U, Np, and Pu) doped B(20) boron clusters An@B(20) (An = U, Np, and Pu) by global minimum structural searches and density functional theory (DFT). Each An@B(20) cluster is confirmed to be a twenty-coordinate complex, which is the highest CN obtained in the chemistry of...