Complete the exercises below. Polydentate ligands can vary in the number of coordination positions they occupy. In each of the following, identify the polydentate ligand present and indicate the probable number of coordination positions it occupies: a. [Co(NH₃)₄ (o-phen)] Cl₃.

Polydentate ligands are molecules that can attach to a central metal atom at multiple coordination sites. This ability allows them to form stable complexes with metal ions, as they create multiple bonds, enhancing the overall stability of the complex. Common examples include ethylenediamine and oxalate, which can bind through two or more donor atoms.

The coordination number refers to the total number of ligand donor atoms that are bonded to a central metal ion in a coordination complex. It is determined by the number of bonds formed between the ligands and the metal. For polydentate ligands, the coordination number can be higher than for monodentate ligands, as they can occupy multiple positions simultaneously.

Chelation is the process by which a polydentate ligand forms a complex with a metal ion, effectively 'grabbing' the metal through multiple coordination sites. This interaction often results in more stable complexes compared to those formed with monodentate ligands. Chelating agents are widely used in various applications, including medicine and environmental science, to sequester metal ions.