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Natural strontium is a mixture of four stable isotopes: 84 Sr, 86 Sr, 87 Sr, and 88 Sr. [11] On these isotopes, 88 Sr is the most abundant, makes up about 82.6% of all natural strontium, though the abundance varies due to the production of radiogenic 87 Sr as the daughter of long-lived beta-decaying 87 Rb. [22] This is the basis of rubidium ...
About 8% by weight of cathode ray tubes is strontium oxide, which has been the major use of strontium since 1970. [3] [4] Color televisions and other devices containing color cathode ray tubes sold in the United States are required by law to use strontium in the faceplate to block X-ray emission (these X-ray emitting TVs are no longer in production).
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.
Of these, three elements (bismuth, thorium, and uranium) are primordial because they have half-lives long enough to still be found on the Earth, [d] while all the others are produced either by radioactive decay or are synthesized in laboratories and nuclear reactors. Only 13 of the 38 known-but-unstable elements have isotopes with a half-life ...
Strontium-86 and strontium-87 are both stable isotopes of strontium, but strontium-87 is radiogenic, coming from the decay of rubidium-87. The ratio of these two isotopes depends on the concentration of rubidium-87 initially and the age of the sample, assuming that the background concentration of strontium-87 is known.
Helium, oxygen, neon, iron—they all come from the fusion that takes place in dying stars. But we have a lot of elements that are more massive than iron ; it’s only element 26 of 118, after all.
Hydrogen atoms are covalently bonded to oxygen in a water molecule but also have an additional attraction (about 23.3 kJ·mol −1 per hydrogen atom) to an adjacent oxygen atom in a separate molecule. [2] These hydrogen bonds between water molecules hold them approximately 15% closer than what would be expected in a simple liquid with just Van ...
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