Complex formation between polyols and rare earth cations. The crystal structure of galactitol · 2PrCl3 · 14 H2O

Alditols form stronger complexes with Nd3+, Sm3+, and Eu3+ than with La3+ cations, but weaker ones with the higher lanthanides. There is a clear relationship between ionic radii and stability constants. Chromatographic ion-exchange columns can be smaller when prepared with Nd3+ rather than the usual Ca2+ columns. Galactitol, alone amongst the hexitols, can form 1:2 complexes with lanthanide ions. The crystal structure of galactitol·2PrCl3·14H2O has been determined.