Page "Astatine" Paragraph 2

The element was first produced by Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè at the University of California, Berkeley in 1940.

They named the element " astatine ", a name coming from the great instability of the synthesized matter ( the source Greek word αστατος ( astatos ) means " unstable ").

Three years later it was found in nature, although it is the least abundant element in the Earth's crust among the non-transuranic elements, with an estimated total amount of less than at any given time.

Six astatine isotopes, with mass numbers of 214 to 219, are present in nature as the products of various decay routes of heavier elements, but neither the most stable isotope of astatine ( with mass number 210 ) nor astatine-211 ( which is used in medicine ) is produced naturally.