Complex ion formation constants – stepwise ligand binding

ChemistryInorganic ChemistryAges 17–18

A ligand does not replace all the water molecules at once; it attaches to the metal ion one step at a time, each step with its own stepwise formation constant (also called stability constant). Drag the ligand concentration to watch the species-distribution diagram for [M(H₂O)ₙ₋ᵢLᵢ] shift, the solution color change with it, and compare NH₃ with ethylenediamine to see the chelate effect make a complex millions of times more stable.