Ag@Mg₁₂@Ag₂₀: a three-layer matryoshka structure with S ₆ symmetry

The C₆₀ fullerene, renowned for its soccer ball-like high-symmetry configuration, has attracted extensive interest. As research on C₆₀ progresses, the synthesis of diverse C₆₀ derivatives and the exploration of embedding varying numbers of atoms within the carbon cage, ranging from singular atoms to entire molecules, have emerged. This trend has prompted investigations into potential high-symmetry structures formed by incorporating main group or transition metal elements. This study presents a detailed analysis of a three-layer Ag@Mg₁₂@Ag₂₀ structure, featuring a Mg₁₂ icosahedron enclosed within an Ag₂₀ dodecahedron with a singular Ag atom at its core. Employing density-functional theory, the structure underwent comprehensive scrutiny, including energy minimization resulting in the adoption of a S ₆ symmetry, and subsequent evaluation of stability via vibrational frequency analysis and molecular dynamics simulations. The electronic structures and bonding characteristics of this three-layer Ag@Mg₁₂@Ag₂₀ architecture were explored through electron density analysis, density of states, and adaptive natural density partitioning analysis. Considering structural stability, the proposed three-layer Ag@Mg₁₂@Ag₂₀ structure exhibits promise as a novel constituent in the construction of other nano-materials.