Science / Chemistry / Polydentate: A ligand that has more than one atom that coordinates directly to the central atom in a complex. Polydentate ligands are called chelating agents when two or more coordinating atoms are attached to the same metal ion in a complex. For example, EDTA or ethylenediaminotetracetic acid is a hexadentate ligand of calcium ion.
Science / Chemistry / Edta: A polydentate ligand that tightly complexes certain metal ions. EDTA is used as a blood preservative by complexing free calcium ion (which promotes blood clotting). EDTA's ability to bind to lead ions MORE
Science / Chemistry / Chelate: A stable complex of a metal with one or more polydentate ligands. For example, calcium complexes with EDTA to form a chelate. MORE