A polydentate phosphine ligand refers to a ligand having a plurality of coordinating atoms in a ligand, and these coordinating atoms are P atoms. Among the polydentate phosphine ligands, P acts as a coordination center atom and has an outer electron configuration of 3S23P3, which is a good electron donor (Lewis base), and at the same time, the low energy 3d empty orbit has the ability to accept electrons. Polydentate Phosphine Ligands https://www.alfachemic.com/catalysts/products/polydentate-phosphine-ligands.html