Stability of metal uncharged ligand complexes in ion exchangers. Part 2.—The copper+ethylenediamine complex in montmorillonite and sulphonic acid resin

Abstract

The thermodynamic stability of the copper+ethylenediamine complex is determined in montmorillonite and a macroreticular sulphonic acid resin using ion exchange data and the complex formation function. Both methods are in excellent agreement and correspond to an increase in the overall stability constant of 10³ for montmorillonite and 10^1·3 for the resin. The stepwise formation constants K₁K₂ of the ion exchanged complex are 10^11·6 and 10^11·5 for montmorillonite and 10^11·65 and 10^9·7 for the resin, as compared with values of 10^10·7 and 10^9·3 for the bulk solution. Some tentative interpretation is offered in terms of a decreased ligand solvation in the ion exchanger.