Rare earth ion complexing with diphosphoric and methylenediphosphoric acids in acid aqueous solution

Using the method of high resolution spectrography the complexing of yttrium and lanthanide (Ln) ions with diphosphoric (H4P) and mehylenediphosphonic (H4Z) acids in aqueous solutions at high concentrations of hydrogen ions is investigated. It is shown that under the conditions studied complexes of the composition LnH-2P(Z)+, stability of which is identically nonmonotonously changes in the series La-Lu, are formed. The values of stability constant logarithm of complexes with H4P and H4Z constitute respectively: La-3.79(4.81); Eu-4.52(5.65); Y-4.30(5.43)