The chemical behaviour of the95Nb atoms formed by the beta decay of the95Zr-Alizarin S and95Zr-TTA (2-thenoyltrifluoracetone) complexes were investigated. The retention values of95Nb which not complexed with organic reagents at working pH were determined. The values observed were 100% and 80%, respectively. The results are discussed and interpreted to explain the different behaviour on the basis of internal energy values and solvent effects.