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This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds. [1]
Considering all decay modes, various models indicate a shift of the center of the island (i.e., the longest-living nuclide) from 298 Fl to a lower atomic number, and competition between alpha decay and spontaneous fission in these nuclides; [83] these include 100-year half-lives for 291 Cn and 293 Cn, [55] [78] a 1000-year half-life for 296 Cn ...
Bismuth-209 was long thought to have the heaviest stable nucleus of any element, but in 2003, a research team at the Institut d’Astrophysique Spatiale in Orsay, France, discovered that 209 Bi undergoes alpha decay with a half-life of 20.1 exayears (2.01×10 19, or 20.1 quintillion years), [3] [4] over 10 9 times longer than the estimated age of the universe. [5]
half-life column The main column shows times in seconds (31,556,926 seconds = 1 tropical year); a second column showing half-life in more usual units (year, day) is also provided. Entries starting with a ">" indicates that no decay has ever been observed, with null experiments establishing lower limits for the half-life.
The most stable of these nuclear isomers is astatine-202m1, [i] which has a half-life of about 3 minutes, longer than those of all the ground states bar those of isotopes 203–211 and 220. The least stable is astatine-213m1; its half-life of 110 nanoseconds is shorter than 125 nanoseconds for astatine-213, the shortest-lived ground state. [5]
^^ Bismuth-209 was long believed to be stable, due to its half-life of 2.01×10 19 years, which is more than a billion times the age of the universe. § Europium-151 and samarium-147 are primordial nuclides with very long half-lives of 4.62×10 18 years and 1.066×10 11 years, respectively.
Francium-223 is the most stable isotope, with a half-life of 21.8 minutes, [8] and it is highly unlikely that an isotope of francium with a longer half-life will ever be discovered or synthesized. [22] Francium-223 is a fifth product of the uranium-235 decay series as a daughter isotope of actinium-227; thorium-227 is the more common daughter. [23]
Six isotopes of flerovium are known, ranging in mass number between 284 and 289; the most stable of these, 289 Fl, has a half-life of ~2.1 seconds, but the unconfirmed 290 Fl may have a longer half-life of 19 seconds, which would be one of the longest half-lives of any nuclide in these farthest reaches of