The element astatine has no uses currently, apart from basic scientific research. Astatine is very scarce in Earth's crust, and its various isotopes have short half-lives. This means that the total amount of astatine at any given time is less than 30 grams.
Astatine is formed by the decay of thorium and uranium, which means it is biologically toxic due to its radioactivity. Its name comes from the Greek word "astatos," which means "unstable." Astatine was first produced by Dale R Carson, K.R. MacKenzie and Emilio Segrè at the University of California in 1940. They used a machine called a cyclotron to bombard an isotope of bismuth (bismuth-209) with accelerated alpha particles. Two other groups came close to discovering astatine; Horia Hulubei and Yvette Cauchois attempted to analyze mineral samples using a high-resolution X-ray apparatus, and Walter Minder observed the radioactivity of radium and claimed it seemed to have another element present. Chemical tests suggested it was like iodine. Due to its scarcity, astatine is only produced when it is needed. The total amount of astatine that has been produced is 0.05 micrograms (0.00000005 grams). Through the use of a mass spectrometer, scientists have confirmed that astatine behaves chemically like other halogens, iodine in particular.