Bidentate ligands are molecules that can attach to a central metal atom at two distinct sites. This dual attachment allows them to form stable complexes, as they create a chelate effect, which enhances the stability of the metal-ligand bond. Common examples of bidentate ligands include ethylenediamine and oxalate. These ligands play a crucial role in coordination chemistry, where they help in the formation of various metal complexes. Bidentate ligands can influence the properties of these complexes, such as their reactivity and solubility, making them important in fields like biochemistry and catalysis.