A hexadentate ligand has 6 lone pairs of electrons which can form co ordinate bonds with the same metal ion.--------------------- behaves as a hexadentate ligand .

Ethylenediaminetetraacetic acid, widely abbreviated as EDTA is a polyamino carboxylic acid and a colourless, water-soluble solid. It is widely used to dissolve limescale. Its usefulness arises because of its role as a hexadentate ligand and chelating agent, i.e., its ability to sequester metal ions such as Ca²⁺ and Fe³⁺.