The electron density of 1-Yb was calculated using restricted Kohn-Sham density functional theory with the PBE functional. The Wiberg Bond Order (WBO) and delocalization index, (Yb-P), are both used to calculate the number of electrons shared between nuclei of interest. For 1-Yb, the average between the two Yb-P interactions result in a (Yb-P) = 0.25 and a WBO of 0.29. The average value of the electron density at the bond critical point for the Yb-P interactions, BCP(Yb-P), is 0.027 a.u., which confirms that these interactions are weak. This is also corroborated with the highest occupied molecular orbital which has a lack of orbital overlap between metal and ligand (see Supporting Information Figure ).