Monodentate ligands

A monodentate ligand has a single donor atom, and that one atom shares one electron pair to form exactly one coordinate bond with the central metal ion. The book's examples are the anionic ligands Cl-, OH- and CN-, whose donor atoms -- chlorine, oxygen and nitrogen respectively -- each carry the lone pair used to bond to the metal (note that in most real coordination compounds CN- coordinates through its carbon atom, but the source text here specifically identifies nitrogen as the listed donor atom for this ligand). Every monodentate ligand contributes exactly one to a complex's total coordination number, which is why, for a complex built entirely from monodentate ligands (like [Co( …