In 1931, American physicist Fred Allison used a magneto-optical machine to analyse minerals, searching for element 85, the unknown element below iodine in the periodic table. He claimed to have discovered it and proposed the name alabamine (symbol Ab) after the state of Alabama where he worked. Other researchers showed that the technique he was using could not detect elements, and we now know he must have been wrong because all isotopes of astatine are particularly short-lived.

In 1937, chemist Jajendralal De, working in Dacca in British India, claimed discovery of element 85 after analysing minerals. He proposed the name dakine, based on one of the variations of spelling Dacca. He too was mistaken.

Slightly more convincing evidence was that produced by others in 1939. Romanian physicist Horia Hulubei (1896–1972) and French chemist Yvette Cauchois (1908–1999) analysed mineral samples using a high-resolution X-ray apparatus and detected the spectroscopy lines in the emission spectrum of radon, claiming this to be element 85. They re-ran the experiment, but because of the disruption caused by World War II, they did no propose a name until 1944 and they chose dor (symbol Do) based on a Romanian word implying ‘better’ and said to be looking forward to the end of the war and better times.

Also in 1939, Swiss chemist Walter Minder (1905–1992) observed weak beta decay in radium. Chemical tests confirmed the analogies of the substance with iodine. This was the new element 85. He announced it the following year and proposed the name helvetium (symbol Hv) based on Helvetia, the official name for Switzerland.

Element 85 was convincingly produced for the first time at the University of California in 1940 by Dale R. Corson (1914– ), K.R. Mackenzie (1912–2002), and Emilio Segré (1905–1989). (Segré was an Italian physicist who had fled from Mussolini’s Italy. He had previously synthesised technetium.) The astatine was made by bombarding bismuth with alpha particles (helium nuclei). Although they reported their discovery, they were unable to carry on with their research due to World War II and the demands of the Manhattan project which diverted all such work into the making of atomic weapons. Only in 1947 were they able to name it astatine.