A Series of Endohedral Metallo-BN Fullerene Superatomic Structures

Superatoms are crucial in the assembly of functional and optoelectronic materials. This study investigates the endohedral metallo-boron nitride [boron nitride (BN)] fullerenes U@B₁₂N₁₂, Cm@B₁₂N₁₂, and U@B₁₆N₁₆ in theory. Our findings confirm that U@B₁₂N₁₂, Cm@B₁₂N₁₂, and U@B₁₆N₁₆ are superatoms and their electronic configurations are 1P⁶1S²1D¹⁰1F¹⁴2P⁶2S²2D¹⁰2F¹²3P⁶, 1P⁶1S²1D¹⁰1F¹⁴1G¹⁶1H¹⁶2S²2P⁶2D¹⁰2F¹², and 1P⁶1S²1D¹⁰1F¹⁴2P⁶2S²2D¹⁰2F¹⁴, respectively. Notably, the orbital energy levels in these superatoms exhibit a flipping phenomenon, deviating from those of previous superatom studies. Further, the orbital composition analyses reveal that superatomic orbitals 1S, 1P, 1D, and 1F mainly originate from BN cages, whereas the 2S, 2P, 2D, 2F, and 3P superatomic orbitals arise from hybridizations between BN cage orbitals and the 7s, 7p, 6d, and 5f orbitals of actinide atoms. And the energy gap of endohedral metallo-BN fullerene superatoms is reduced by introducing actinide atoms. Additionally, the analyses of ionization potentials and electron affinities show that U@B₁₂N₁₂, Cm@B₁₂N₁₂, and U@B₁₆N₁₆ have lower ionization potentials and higher electron affinities, suggesting decreased stability compared to that of pure BN cages. This instability may be linked to the observed flipping of the superatomic orbital energy levels. These insights introduce new members to the superatom family and offer new building blocks for the design of nanoscale materials with tailored properties.