Discovery date : 1940
Discovered by: Dale R. Corson, Kenneth Ross MacKenzie, Emilio Segrè
Origin of the name: The name comes from the Greek 'astatos', meaning unstable.
Allotropes : -
~>ASTATINE is a radioactive chemical element with symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth crust, occurring only as the decay product of various heavier elements.
| FACT BOX | |||
| Group | 17 | Melting point | 300°C, 572°F, 573 K |
| Period | 6 | Boiling point | 350°C, 662°F, 623 K |
| Block | d | Density (g cm−3) | Unknown |
| Atomic number | 85 | Relative atomic mass | [210] |
| State at 20°C | Solid | Key isotopes | 210At,211At |
| Electron configuration | [Xe] 4f145d106s26p5 | CAS number | 7440-68-8 |
| ChemSpider ID | 4573995 | ChemSpider is a free chemical structure database | |
In 1939, two groups came near to discovering this element in mineral samples. Horia Hulubei and Yvette Cauchois analysed mineral samples using a high-resolution X-ray apparatus and thought they had detected it. Meanwhile, Walter Minder observed the radioactivity of radium and said it appeared have another element present. He undertook chemical tests which suggested it was like iodine.
Element 85 was convincingly produced for the first time at the University of California in 1940 by Dale R. Corson, K.R. Mackenzie, and Emilio Segré. Their astatine was made by bombarding bismuth with alpha particles. 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 researchers of radioactive materials towards the making of nuclear weapons.