On the hydrolysis of the Dysprosium(III) ion

The hydrolysis of the Dysprosium (III) (Dy3+) ion has been investigated at 25degreesC in 1, 2 and 3 molal (Na)ClO4 medium through a combined potentiometric-coulometric methodology. At each perchlorate concentration the formation constants of the complexes DyOH2+, Dy-2(OH)(2)(4+) and Dy-5(OH)(9)(6+) have been determined. The values have then been extrapolated to zero ionic strength by using the Specific Interaction Theory. Analogies with the hydrolysis mechanism of other lanthanides are pointed out. This paper is just the first to be reported of a series of studies undertaken with the aim to prove that a single mechanism of hydrolysis applies to all the trivalent lanthanides and probably to the corresponding actinides, too radioactive to be investigated directly.