Figures and provide an overview of the number of atoms in tridentate ligands. Figure shows the total number of atoms (green dots) and non-hydrogen atoms (red dots) plotted versus the originating transition metal center. These plots show that for about half of the transition metal atoms there is a nearly continuous size of ligands ranging from 10-90 total atoms. Figure provides a similar analysis of total ligand atoms and non-hydrogen atoms but plotted versus the type of tridentate ligand (the three atoms that directly connect to the metal center) rather than the originating transition metal center. total number of all hydrogen atoms in tridentate ligands plotted versus the type of tridentate ligand (connecting atoms to metal center).