World’s Rarest Element- Astatine is a radioactive chemical element with the chemical symbol At and atomic number 85. It occurs on Earth only as the result of the radioactive decay of certain heavier elements. All of its isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours.
Accordingly, much less is known about astatine than most other elements. The observed properties are consistent with it being a heavier analog of iodine; many other properties have been estimated based on this resemblance.
“Astatine is of particular interest because its isotopes are interesting candidates for the creation of radiopharmaceuticals for cancer treatment by targeted alpha therapy,” Andrei Andreyev, lead researcher of the CERN study, said.
According to the NIH, targeted alpha therapy uses radioactive particles of heavy elements, which “release enormous energy over a short distance … providing a more specific tumor cell killing ability without damage to the surrounding normal tissues.”
“Even though these α-emitters have favorable properties, the development of TAT has been limited by high costs, unresolved chemistry, and limited availability of the radionuclides,” the NIH report continues. “To overcome these limitations, more potent isotopes, additional sources, and more efficient isotope production methods should be addressed.”
World’s Rarest Element- Astatine might be one of those more potent isotopes. Its extremely short half life means that radiation exposure to patients would be lower than existing treatments, and it generally decays back into bismuth, a heavy metal with extremely low toxicity.
World’s Rarest Element- is the least reactive of the halogens, being less reactive than iodine; however, multiple compounds of astatine have been synthesized in microscopic amounts and studied as intensively as possible before their inevitable radioactive disintegration. The reactions involved are normally tested with dilute solutions of astatine mixed with larger amounts of iodine. The iodine acts as a carrier, ensuring that there is sufficient material for laboratory techniques (such as filtration and precipitation) to work.
The formation of an astatine compound with hydrogen – usually referred to as hydrogen astatide – was noted by the pioneers of astatine chemistry. As mentioned earlier, there are grounds for referring to this compound as astatine hydride instead – astatine is easily oxidized, acidification by (dilute) nitric acid gives the At0 or At+forms, and the addition of silver(I) then precipitates astatine, only partially as silver(I) astatide (AgAt) (or not at all). Iodine, in contrast, is not oxidized, and precipitates readily as silver(I) iodide.