transmutation

Transmutation is the process of changing one chemical element into another. In scientific contexts, the term encompasses chemical transmutation, historically associated with alchemy, and nuclear transmutation, in which changes occur in the atomic nucleus. Chemically, elements cannot be converted into different elements by ordinary reactions; transmutation in chemistry is largely of historical interest or used metaphorically.

Nuclear transmutation occurs when the nucleus is altered by nuclear reactions. This can happen through radioactive decay, when a parent nuclide becomes a different element; or through reactions driven by neutrons or charged particles, such as neutron capture, fission, spallation, or bombardment in accelerators or reactors. Transmutation can produce new isotopes, including those not found naturally, or convert long‑lived radioactive waste into shorter‑lived or stable nuclides.

Applications include the production of medical isotopes (for example technetium‑99m and other diagnostic or therapeutic nuclides), the synthesis of new elements, and strategies for nuclear waste management. Transmutation is studied in accelerator‑driven systems and fast reactors as a way to reduce radiotoxicity by transforming certain long‑lived isotopes.

Limitations include technical complexity, energy requirements, material damage from radiation, and economics. While nuclear transmutation can change elemental identity, it is not a universal substitute for waste containment or natural radiological decay and remains specialized to appropriate isotopes and facilities.

See also alchemy, radiochemistry, nuclear physics, isotopes.