SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS .31. ION-EXCHANGE BEHAVIOR OF TERVALENT METALS AND RARE-EARTH ELEMENTS ON CRYSTALLINE ANTIMONIC(V) ACID CATION EXCHANGER

The increasing order of ion-exchange selectivity for tervalent metal ions: Al**3** plus very much less than Ga**3** plus less than or equal to Yb**3** plus less than Fe**3** plus less than La**3** plus less than In**3** plus , was established in 1 mol dm** minus **3 nitric acid solution on a crystalline antimonic(V) acid (C-SbA) cation exchanger. Strong correlation was found between the selectivity and the effective ionic radii of these ions. Large separation factors for neighboring ions were obtained, as compared with the commercial ion exchange resin. An effective separation of aluminum(III)-iron(III) ion pairs and a group separation of garium(III) and ytterbium-(III) ions from lanthanum(III) ion were performed by using a relatively small C-SbA column (4 cm multiplied by 0. 4 cm i. d. ).