Search for the 'House' of icosahedral B₁₂: structural evolution and stability of core-shell boron clusters

Boron's inherent electron deficiency drives its aggregation into versatile structures, forming the basis for diverse allotropes. The B₁₂icosahedron serves as an essential building block for solid boron but, when isolated, suffers from electronic frustration associated with unsatisfied bonding requirements. As a regulatory environment to resolve this frustration, large boron clusters tend to form core-shell structures. This review establishes an evolutionary roadmap for the 'House' of icosahedral B₁₂, providing a crucial missing link between 0D molecular seeds and 3D condensed phases. We summarize recent experimental and theoretical advances, focusing on structural characteristics and functionalities of clusters such as B₅₄, the experimentally validated B₅₆^-, and larger clusters including B₈₀and B₉₂. Furthermore, we discuss the 'anchor effect' of B₁₂-acting as a structural and electronic template-in derived systems (B₁₂@M₂₀A₁₂(M=Li, Ca, Mg, Al;A=B, C, N, Al) and B₁₂@Ca₁₄) for hydrogen storage, highlighting their potential to inhibit metal aggregation. Challenges in the field and prospects for future development are also discussed.