Two types of layered zirconium polyimines have been synthesized. Monop
hosphonic acid head groups attached to polyimine chains form layered c
ompounds with Zr-(IV) salts in which the Polyimine chains form bilayer
s in the interlamellar space. Upon protonation, the layers disperse, f
orming colloidal solutions. These free-floating polyimines readily enc
apsulate large polyvalent anions, accompanied by quantitative precipit
ation. Diphosphonic acids cross-link the layers and behave as insolubl
e anion exchangers in acid solution and as cryptates in neutral or alk
aline media.