Table . Experimental and weighted averages of calculated (using the B3LYPHF40 functional) isotropic The frontier Kohn-Sham molecular orbitals (KSMOs) of 1-La (Figure ) are as expected, with the HOMO to HOMO-2 reflecting the symmetric and anti-symmetric combinations of the three La-Si bonds. However, these KSMOs are rather delocalized, and so we turned to bond localization methods. The Natural Bond Orbital (NBO) method finds three essentially identical La-Si bonds (Figure ) of 11 and 89% La and Si character, respectively. similar orbital breakdowns have previously been calculated for other La silanide complexes. These data are very similar to the Natural Localized Molecular Orbital (NLMO) representations of 1-La (Figure ), which return 11 and 87% La and Si character, respectively. The La and Si components are 35/1/62/2% s/p/d/f and 41/59% s/p. Thus, whilst the NLMO report increased s-character at the expense of d-contributions for La compared to the NBO interpretation, a fairly consistent bonding picture emerges of La binding to sp hybridized Si atoms utilizing sd 3 hybrid orbitals.