a substance (an atom or molecule or radical or ion) that forms a complex around a central atom
"The chemist mixed copper ions with ammonia to create a ligand complex where the nitrogen atoms bonded tightly to the metal center."
A molecule or moiety (ion, functional group, or radical) that binds to another chemical entity to form a larger complex; as, especially:
"In the lab, we added excess chloride ions as ligands to the silver nitrate solution to ensure every metal center was fully coordinated."
Such an entity that binds to a central metal atom to form a coordination complex.
"In the lab, researchers added ammonia as a ligand so it could bind directly to the copper ion and stabilize the resulting coordination complex."