The unoccupied conduction bands are also mixed with Sb-p and Al-p character from the (Sb 3 ) 7-trimers and (M Sb 4 ) m-tetrahedra. Notably, there are four distinctly low-energy conduction bands that are isolated from the rest of the conduction bands in Yb 14 MgSb 11 , which we call the σ * bands (Figure ). These bands form a narrow peak in the DOS ∼ 1 eV above the Fermi energy (Figure ) and are primarily of (Sb 3 ) 7-character. The charge density distribution of the σ * bands (Figure ) shows that the bands are antibonding states of the (Sb 3 ) 7-trimer unit. The antibonding character is evidenced by the nodal features of the charge density, where the wave function is zero between the middle Sb atom and the ends of the trimer, owing to the destructive interference of p-orbitals aligned along the axis of the trimer unit.