THE EFFECT OF BETA-DECAY ON THE EXCHANGE PROPERTIES OF THE RARE EARTH–EDTA COMPLEX IONS

Abstract

It is shown that the rare earth ion Yb3+ is very resistant towards ordinary thermal exchange when it is complexed with the chelating agent EDTA in aqueous solution. However, when the complexed rare earth atom, as the 1.8-h Yb-177, emits a beta-particle, the daughter atom Lu-177 escapes readily from the chelate structure. Nuclear recoil arising from the beta-particle emission is shown not to be the cause of the escape of the daughter atom. It is suggested that the observed lability of the daughter atom is a result of a high degree of chemical reactivity of the chelate ion arising from the sudden change in atomic number of the central metal ion of the chelate structure.