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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.
The biological half-life of curium is about 20 years in the liver and 50 years in the bones. [53] [55] Curium is absorbed in the body much more strongly via inhalation, and the allowed total dose of 244 Cm in soluble form is 0.3 μCi. [14]
The longest-lived isotope is 247 Cm, with half-life 15.6 million years – orders of magnitude longer than that of any known isotope beyond curium, and long enough to study as a possible extinct radionuclide that would be produced by the r-process. [2] [3] The longest-lived known isomer is 246m Cm with a half-life of 1.12 seconds.
Curium-250 is the isotope with the lowest atomic number that primarily decays by spontaneous fission, a process that releases many times more energy than alpha decay. Compared to plutonium-238, curium-250 provides about a quarter of the power density, but 95 times the half-life (~8300 years vs. ~87 years).
Curium metal is a radionuclide and emits alpha particles upon radioactive decay. [12] Although it has a half life of 34 ms, many curium oxides, including curium sesquioxide, have half lives nearing thousands of years. [7] Curium, in the form of curium sesquioxide, can be inhaled into the body, causing many biological defects.
In this situation it is generally uncommon to talk about half-life in the first place, but sometimes people will describe the decay in terms of its "first half-life", "second half-life", etc., where the first half-life is defined as the time required for decay from the initial value to 50%, the second half-life is from 50% to 25%, and so on.
Global shortages of nuclear chemical needed for cancer scans will see patients’ appointments cancelled, minister warns
The resulting complexes show strong yellow-orange emission under UV light excitation, which is convenient not only for their detection, but also for studying interactions between the Cm 3+ ion and the ligands via changes in the half-life (of the order ~0.1 ms) and spectrum of the fluorescence.