THE COMPLEXOMETRIC ANALYSIS OF THE COPPER AND NICKEL CONTENT IN CO-PRESENCE IN THE COORDINATION COMPLEXES WITH NITRILO-<i>tris</i>(METHYLENEPHOSPHONIC ACID)
Procedure and results of quantitative analysis of copper and nickel content in co-presence in crystalline samples of mixed complexes with nitrilo-tris-methylene phosphonic acid of formula [Cu <sub>x</sub> Ni<sub>(1- x )</sub>{N(CH<sub>2</sub>PO<sub>3</sub>)<sub>3</sub>}]Na<sub>4</sub>· n H<sub>2</sub>O obtained by crystallization from aqueous solutions with different Cu:Ni atomic ratio are given. The results show that the composition of the resulting crystalline products depends on the Cu:Ni ratio in the solution, and there is an energy barrier for replacing the atoms of the predominant metal in the crystalline phase. Crystals with a Cu:Ni ratio equal to Cu:Ni ratio in solution are formed at an atomic fraction of copper in solution about ¼.