Complex Ion Equilibrium
The equilibrium between a metal ion, its ligands and the resulting complex ion in solution.
Formula / equation
M + nL ⇌ MLₙ
Unit
mol/L
In depth
Complex formation lowers the free metal ion concentration dramatically, which can dissolve precipitates that would otherwise be insoluble and can mask ions in analysis. It also underlies the extraction of metals and the action of many chelation therapies.
Examples in the real world
AgCl dissolving in aqueous ammonia as [Ag(NH₃)₂]⁺ forms and depletes the free Ag⁺.