The specific phenomena accompanying the daughter nuclide formation by radioactive β-decay of complex parent compounds cause
certain deviations from a thermodynamic distribution of daughter elements in separation procedures (e.g. in radionuclidic
generators) and they are shown to complicate or, less probably, simplify their separation. A simple kinetic model has been
proposed to explain such processes as the distribution of some daughter nuclides of fission products by solvent extraction
with chelating compounds (systems of99Mo−99mTc and144Ce−144Pr with oxines).