- A number of layered zirconium phosphite arylphosphonate and zirconium phosphate arylphosphonate mixed derivatives have been prepared. These compounds were readily sulfonated in fuming sulfuric acid and the resultant sulfonates behaved as strong-acid ion exchangers. In the case where the aryl group bridged across layers, a non-swelling exchanger resulted, and these solids showed ion exclusion towards large complexes. They also exhibited the selectivity sequences Li+ > Na+ < K+ and Mg2+ > Ca2+ < Ba2+. In the exchanger in which the layers were not connected, large degrees of swelling, to the point of colloid formation, were observed. As a consequence, the rates of exchange were very high. The non-crosslinked exchanger showed increased selectivity for larger cations. In the case of coordination complexes the increased selectivity was remarkable and may stem from a combination of favorable electrostatic and steric factors. 1987.