Astatine is a chemical element that has no stable isotopes (it is radioactive). The most stable isotope of the element is astatine-210, which has a half life of 8.1 hours. Despite this fact, trace amounts of astatine (At215, At218 and At219) can be found on earth as the result of radioactive decay. It is the rarest of all naturally occurring elements (there is less than 25 grams in the crust of the earth) and it is for this reason, along with its short lives nature, that much less is known about this element than other naturally occurring elements. It is also the reason that it was discovered much later than other natural elements. Let’s find out who discovered astatine and when it was discovered.
Who discovered astatine?
The discovery of astatine was claimed by many people before the first success was made. The discovery is credited to Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè who decided to try and create the element rather than trying to find it in nature. They used a particle accelerator to bombarded bismuth-209 with alpha particles and produced astatine-211. This name comes from the Greek word ástatos, meaning “unstable.”
The first claimed discovery came in 1931 by Fred Allison and his associates. The second claim was made by 1937 chemist Rajendralal De and the third was made in 1940 by Swiss chemist Walter Minder (he would make another claim in 1942 together with English scientist Alice Leigh-Smith). However, all of these claims were unable to be verified.
Did you know?
The prediction of the element came after Dmitri Mendeleev published his first periodic table in 1869. He left the space blank and it was soon suggested that another element belonged there. Before it was discovered it was called “eka-iodine”