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Naturally occurring strontium is nonradioactive and nontoxic at levels normally found in the environment, but 90 Sr is a radiation hazard. [4] 90 Sr undergoes β − decay with a half-life of 28.79 years and a decay energy of 0.546 MeV distributed to an electron, an antineutrino, and the yttrium isotope 90 Y, which in turn undergoes β − decay with a half-life of 64 hours and a decay energy ...
Examples include carbon-14, nitrogen-15, and oxygen-16 in the table above. Isobars are nuclides with the same number of nucleons (i.e. mass number) but different numbers of protons and neutrons. Isobars neighbor each other diagonally from lower-left to upper-right. Examples include carbon-14, nitrogen-14, and oxygen-14 in the table above.
The mean strontium content of ocean water is 8 mg/L. [50] [51] At a concentration between 82 and 90 μmol/L of strontium, the concentration is considerably lower than the calcium concentration, which is normally between 9.6 and 11.6 mmol/L. [52] [53] It is nevertheless much higher than that of barium, 13 μg/L. [11]
Strontium-90 has been used in radioisotope thermoelectric generators (RTGs) in the past because of its relatively high power density (0.95 W thermal /g for the metal, 0.46 W thermal /g for the commonly used inert perovskite form Strontium titanate) and because it is easily extracted from spent fuel (both native Strontium metal and Strontium ...
The longest-lived of these isotopes, and the most relevantly studied, are 90 Sr with a half-life of 28.9 years, 85 Sr with a half-life of 64.853 days, and 89 Sr (89 Sr) with a half-life of 50.57 days. All other strontium isotopes have half-lives shorter than 50 days, most under 100 minutes.
These use heat produced by radioactive decay of strontium-90 to generate heat, which can be converted to electricity using a thermocouple. Strontium-90 has a shorter half-life, produces less power, and requires more shielding than plutonium-238 , but is cheaper as it is a fission product and is present in a high concentration in nuclear waste ...
nitrogen-10: 143(36) oxygen-11: 198(12) helium-10: 260(40) hydrogen-6: 294(67) lithium-5: 370(30) fluorine-14: 500(60) boron-7: 570(14) nitrogen-11: 585(7) helium-5: 602(22) beryllium-16: 650(130) hydrogen-7: 652(558) nitrogen-11m: 690(80) boron-21 > 760: neon-15: 770(300) beryllium-15: 790(270) boron-20 > 912.4: beryllium-11m: 930(130)
An even number of protons or neutrons is more stable (higher binding energy) because of pairing effects, so even–even nuclides are much more stable than odd–odd. One effect is that there are few stable odd–odd nuclides: in fact only five are stable, with another four having half-lives longer than a billion years.