Figure 7: Kohn–Sham molecular orbital representations of the principal Th–P interactions of 3−.
From: Thorium–phosphorus triamidoamine complexes containing Th–P single- and multiple-bond interactions

HOMO−1 (a, −0.394 eV) and HOMO (b, −0.374 eV) represent the two principal thorium–phosphorus covalent σ- and π-bonding interactions in the anion component of 3.