ABSTRACT
The radioactive isotopes found in nature (about 80) are largely exceeded in number by those made by man (over 2500). Artificial radionuclides are obtained usually in nuclear reactions induced by the bombardment of a target nuclide with charged particles or with neutrons. This chapter deals with various chemical aspects of nuclear processes.
In many nuclear reactions a significant amount of energy is released by the transformation of mass into energy. This conversion is particularly important in the fission reaction , in which a target nucleus splits into two fragments. The fission of uranium induced by neutrons is the basic reaction for nuclear energy.
In radioactive decays and in nuclear reactions the nuclides are formed with kinetic energies which may be higher than the energy of chemical bonds. These species are known as “hot atoms ”. They permit the study of chemical reactions of energy-rich entities. Hot atoms intervene frequently in geochemistry and cosmochemistry and are convenient for the fast synthesis of molecules labeled with short-lived radionuclides.
A unique feature of radioactive decay is the transmutation effect by which the chemical identity of the daughter nucleus differs from that of the parent. Such effects can be used for the decay-induced synthesis of new molecules; they may have played a role in the formation of precursors of biomolecules on the early Earth and are likely still important for cosmic chemistry.
The chemical environment may influence nuclear properties and a very weak change of half-life is observed in a few instances.
