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Naturally occurring europium (63 Eu) is composed of two isotopes, 151 Eu and 153 Eu, with 153 Eu being the most abundant (52.2% natural abundance).While 153 Eu is observationally stable (theoretically can undergo alpha decay with half-life over 5.5×10 17 years), 151 Eu was found in 2007 to be unstable and undergo alpha decay. [4]
Naturally occurring europium is composed of two isotopes, 151 Eu and 153 Eu, which occur in almost equal proportions; 153 Eu is slightly more abundant (52.2% natural abundance). While 153 Eu is stable, 151 Eu was found to be unstable to alpha decay with a half-life of 5 +11
The darker more stable isotope region departs from the line of protons (Z) = neutrons (N), as the element number Z becomes larger. This is a list of chemical elements by the stability of their isotopes. Of the first 82 elements in the periodic table, 80 have isotopes considered to be stable. [1] Overall, there are 251 known stable isotopes in ...
There are no stable nuclides with mass numbers 5 or 8. There are stable nuclides with all other mass numbers up to 208 with the exceptions of 147 and 151, which are represented by the very long-lived samarium-147 and europium-151. (Bismuth-209 was found to be radioactive in 2003, but with a half-life of 2.01 × 10 19 years.)
The graph reflects the fact that elements with more than 20 protons either have more neutrons than protons or are unstable. ... § Europium-151 and samarium-147 are ...
Research at Laboratori Nazionali del Gran Sasso showed that europium-151 decays to promethium-147 with the half-life of 5 × 10 18 years; [29] later measurements gave the half-life as (4.62 ± 0.95(stat.) ± 0.68(syst.)) × 10 18 years. [30] It has been shown that europium is "responsible" for about 12 grams of promethium in the Earth's crust. [29]
At least 3,300 nuclides have been experimentally characterized [1] (see List of radioactive nuclides by half-life for the nuclides with decay half-lives less than one hour). A nuclide is defined conventionally as an experimentally examined bound collection of protons and neutrons that either is stable or has an observed decay mode.
Samarium-151 (151 Sm) has a half-life of 94.6 years, undergoing low-energy beta decay, and has a fission product yield of 0.4203% for thermal neutrons and 235 U, about 39% of 149 Sm's yield. The yield is somewhat higher for 239 Pu .