Merging boron solid state and molecular chemistry: Energy landscapes in the exo/endo closo-borane complex Sc[B24H24]+

► Crystal structure of ScB12 suggests the possible existence of closo B24H242-. ► Shrinkage plus pseudorotation of B24 truncated octahedron in ScB12 relates crystal and molecular structure. ► Exohedral and endohedral [Sc⋯B24H24]+ complexes are characterized with quantum-chemical computations. ► The B24H242- optimized molecular structure exists as a building block in the NaZn13-type structure, among others.