syntheticelement

A synthetic element is a chemical element that has been produced by human-made nuclear reactions and is not found in nature in detectable quantities. The lightest synthetic element is technetium (atomic number 43); promethium (61) is also typically regarded as synthetic. The majority of synthetic elements lie beyond uranium (atomic number 92) on the periodic table, and all known synthetic elements are radioactive, with only unstable isotopes observed.

Production of synthetic elements occurs in nuclear reactors or particle accelerators by bombarding target nuclei with neutrons, protons, or heavier ions. Reactions include neutron capture followed by beta decay, fusion-evaporation, and projectile fragmentation. Isolating and identifying these elements requires rapid chemical separation and measures to manage intense radioactivity.

Because many synthetic elements have very short half-lives, detailed chemical properties are known only for a subset. They are typically placed in the actinide series or the transactinide series, and their study expands understanding of nuclear structure, the limits of the periodic table, and relativistic effects on electron behavior in heavy atoms.

Applications and significance of synthetic elements are largely research-oriented, though some have practical uses. Technetium-99m is widely used in medical imaging; americium-241 is used in some smoke detectors; californium-252 serves as a neutron source. Heavier transactinides, such as oganesson, are primarily of interest for fundamental physics experiments, while many other synthetic elements contribute to the exploration of nuclear reactions, element discovery, and the properties of matter at extreme atomic numbers.