Four pillared metal(IV) phosphate-phosphonate ion exchange materials were synthesized and characterized. Studies were conducted to determine their affinity for the lanthanides (Ln's) and actinides (An's). It was determined that by simply manipulating the metal source (Zr or Sn) and the phosphate source (H 3PO 4 or Na 3PO 4) large differences were seen in the extraction of the Ln and An species. Kd values higher than 4 ×10 5 were observed for the AnO 22+ species in nitric acid at pH 2. These basic uptake experiments are important, as the data they provide may indicate the possibility of a separation of Ln's from An's or even more notably americium from curium and Ln's. © by Oldenbourg Wissenschaftsverlag, München/.