The (Sb 3 ) 7-linear trimer unit is isoelectronic to the triiodide ion I - 3 and therefore has similar molecular orbitals (Figure ). The relative phases of the Sb-p orbitals in (Sb 3 ) 7- lead to distinct molecular orbital energies based on whether the neighboring interactions are bonding, antibonding, or nonbonding, as well as their configurations (i.e., whether they are σ-or π-oriented, see Figure ). When the p-orbitals of all three Sb atoms align in-phase along the axis of the trimer unit, the lowest-energy σ bonding state will form. However, if the neighboring interactions are out-of-phase instead, then the highest-energy σ * antibonding state will form. Due to the linear structure of the (Sb 3 ) 7-trimer, there is only one σ bonding state and one σ * antibonding state. Additionally, the p-orbitals of the Sb atoms can align perpendicular to the axis of the trimer unit, forming doublet π bonding and doublet π * antibonding states. The π and π * states are closer in energy than the σ and σ * states, as π-bonds are typically weaker than σ-bonds . Moreover, there are nonbonding states both in the σ and π configurations. In total, each (Sb 3 ) 7-trimer unit contributes nine bands (two σ-type, four π-type, and three nonbonding) to the electronic structure of Yb The molecular orbital diagram of the (AlSb 4 ) 9-tetrahedral unit (Figure ) is constructed following the methodology of Toriyama et al. The bonding a 1 state of (AlSb 4 ) 9-is a molecular orbital in which the a 1 state of the Sb 4 complex, which appears as dumbbell-like orbitals at each corner of the tetrahedron oriented towards the central Al atom, interferes constructively with the s-orbital of the central Al atom. Due to the constructive interference, we expect the charge density for the a 1 state to be high between the central Al atom and the surrounding Sb 4 complex, as in the charge density shown in Figure . On the other hand, the destructive interference leads the formation of a * 1 state. Moreover, we expect from molecular orbital theory that the a 1 bonding state of (AlSb 4 ) 9-consists of Al-s, Sb-s, and Sb-p character by symmetry, all of which are reflected in the a 1 peaks in the orbitaldecomposed DOS in Figure . As a result, the a 1 bands in Yb 14 M Sb 11 correspond exactly to the a 1 bonding state shown in Figure as expected from molecular orbital theory, where we have four a 1 bands since there are four (M Sb 4 ) m-tetrahedral units per primitive cell.