Search for the ‘House’ of icosahedral B ₁₂ : structural evolution and stability of core–shell boron clusters

Abstract Boron’s inherent electron deficiency drives its aggregation into versatile structures, forming the basis for diverse allotropes. The B 12 icosahedron 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 B 12 , 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 B 54 , the experimentally validated B 56 − , and larger clusters including B 80 and B 92 . Furthermore, we discuss the ‘anchor effect’ of B 12 —acting as a structural and electronic template—in derived systems (B 12 @ M 20 A 12 ( M =Li, Ca, Mg, Al; A =B, C, N, Al) and B 12 @Ca 14 ) for hydrogen storage, highlighting their potential to inhibit metal aggregation. Challenges in the field and prospects for future development are also discussed.