When we talk about the rarest element on Earth, we are talking about Astatine, with the symbol At, which is found in the earth’s crust in a tiny amount: about 70 milligrams. The whole Astatine in the world weighs about as much as 10 ants. Together with fluorine, chlorine, and iodine, astatine belongs to the group of so-called halogens and arises in the earth’s crust as a result of uranium decay. The serial number of astatine in the periodic table is 85, and it is the 21st non-metal.
According to Jefferson Lab, Astatine derives its name from the Greek word “astatos”, meaning unstable.
How much does astatine cost per gram?
This element is so rare that you won’t find any costs associated with buying one because no public sales have occurred before. Even if someone sold an authentic specimen to a private buyer for millions of dollars, it would likely expire after several months in controlled conditions due to its short lifespan and unstable nature.
Important things to consider
Its existence has been predicted since the 1800s but was discovered only 70 years later. Even so, more than 100 years after its discovery, not much is known about it. In its most stable form – astatine-210 – it has a half-life of only 8 hours, which means that even if you found a piece of astatine 210 in 8 hours, half of it will no longer exist. Depending on how it decomposes, it will turn into the isotope bismuth-206 or polonium-210.
Corson, MacKenzie, and Segre first synthesized astatine at the University of California in 1940 by bombarding bismuth with alpha particles. Astatine can be produced by bombarding bismuth with alpha energy particles to produce At-209, At-210, and At-211.
Together with fluorine, chlorine, and iodine, astatine belongs to the group of so-called halogens. According to scientists, halogen elements, including astatine, have similar properties; they are non-metallic, have low melting and boiling points, are brittle when solid, are weak conductors of heat and electricity, and are diatomic (their molecules contain two atoms).
The physical properties of astatine, including its color, are unknown due to a lack of results from past experiments. However, based on the colors shown by other members in the halogen family, such as chlorine and iodine that have been measured through various means throughout history, it is believed that Astatine may be dark or close to black.
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Chemicool discusses how astatine is the least reactive and has more metallic properties than any other element in the halogen group.
Its rarity makes it a challenging element to study. However, some researchers believe that astatine may have uses in the treatment of cancer. Astatine can behave like iodine, which tends to collect in the thyroid gland. Astatine can also go to the thyroid, and its radiation could kill cancer cells in the gland.
Given that it is a radioactive element with a short lifespan, a possible application would be in the treatment of cancer in so-called radiotherapy. Following radioactive decay, astatine emits extremely aggressive alpha radiation. This radiation can be much more effective at destroying diseased tissue than the so-called beta radiation often used in radiotherapy. Obviously, it is extremely important that the radiation reaches the tumor tissue and not healthy tissue, as it can cause significant damage to the latter. Therefore, we can imagine a treatment based on an artificial astatine product that manages to eradicate a well-located tumor.
Scientists must be cautious around astatine. As mentioned above, this radioactive element can collect in the thyroid gland, which has detrimental effects on long-term health if it isn’t properly handled. Fortunately, this dangerous substance is rare enough for consumers that individuals do not usually need to worry about their exposure risks. Regarding the scientists, they are well trained on taking special precautions when working with it, so no accident occurs.
Despite its rarity, Astatine is the subject of extensive laboratory investigation. Scientists are interested in learning more about all elements found on Earth because they could contribute to future discoveries and applications for practical use like commercial products or technology. Yet, this element has no commercial use.
Where does astatine fall? It’s a question that has scientists divided. Some classify it as nonmetal, while others place it in the metalloids group with its neighboring elements boron and silicon. To be clear, no one knows for sure where to put this metal because of how unstable it is. Some even say it doesn’t exist at all.