Dale R. Corson, Kenneth Ross MacKenzie, Emilio Segrè (1940)
Isotopes of astatine
v
e
Main isotopes[5]
Decay
abundance
half-life (t1/2)
mode
product
209At
synth
5.41 h
β+
209Po
α
205Bi
210At
synth
8.1 h
β+
210Po
α
206Bi
211At
synth
7.21 h
ε
211Po
α
207Bi
Category: Astatine
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Astatine is a chemical element; it has symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth's crust, occurring only as the decay product of various heavier elements. All of astatine's isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours. Consequently, a solid sample of the element has never been seen, because any macroscopic specimen would be immediately vaporized by the heat of its radioactivity.
The bulk properties of astatine are not known with certainty. Many of them have been estimated from its position on the periodic table as a heavier analog of fluorine, chlorine, bromine, and iodine, the four stable halogens. However, astatine also falls roughly along the dividing line between metals and nonmetals, and some metallic behavior has also been observed and predicted for it. Astatine is likely to have a dark or lustrous appearance and may be a semiconductor or possibly a metal. Chemically, several anionic species of astatine are known and most of its compounds resemble those of iodine, but it also sometimes displays metallic characteristics and shows some similarities to silver.
The first synthesis of astatine was in 1940 by Dale R. Corson, Kenneth Ross MacKenzie, and Emilio G. Segrè at the University of California, Berkeley. They named it from the Ancient Greek ἄστατος (astatos) 'unstable'.[6] Four isotopes of astatine were subsequently found to be naturally occurring, although much less than one gram is present at any given time in the Earth's crust. Neither the most stable isotope, astatine-210, nor the medically useful astatine-211 occur naturally; they are usually produced by bombarding bismuth-209 with alpha particles.
^ abArblaster, JW, ed. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. p. 604. ISBN 978-1-62708-154-2.
^Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 28. ISBN 978-0-08-037941-8.
^Rothe, S.; Andreyev, A. N.; Antalic, S.; Borschevsky, A.; Capponi, L.; Cocolios, T. E.; De Witte, H.; Eliav, E.; et al. (2013). "Measurement of the First Ionization Potential of Astatine by Laser Ionization Spectroscopy". Nature Communications. 4: 1–6. Bibcode:2013NatCo...4E1835R. doi:10.1038/ncomms2819. PMC 3674244. PMID 23673620.
^Hermann, A.; Hoffmann, R.; Ashcroft, N. W. (2013). "Condensed Astatine: Monatomic and Metallic". Physical Review Letters. 111 (11): 116404-1–116404-5. Bibcode:2013PhRvL.111k6404H. doi:10.1103/PhysRevLett.111.116404. PMID 24074111.
^Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
^"Astatine (At) | AMERICAN ELEMENTS". American Elements: The Materials Science Company. Retrieved 4 April 2024.
Astatine is a chemical element; it has symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth's crust, occurring only...
Astatine compounds are compounds that contain the element astatine (At). As this element is very radioactive, few compounds have been studied. Less reactive...
Astatine (85At) has 41 known isotopes, all of which are radioactive; their mass numbers range from 188 to 229 (though 189At is undiscovered). There are...
less frequently so classified: carbon, aluminium, selenium, polonium and astatine. On a standard periodic table, all eleven elements are in a diagonal region...
as astatine hydride, astatane, astatidohydrogen or hydroastatic acid, is a chemical compound with the chemical formula HAt, consisting of an astatine atom...
of astatine would be 147 pm. With the seven outermost electrons removed, tennessine is finally smaller; 57 pm for tennessine and 61 pm for astatine. The...
more different halogen atoms (fluorine, chlorine, bromine, iodine, or astatine) and no atoms of elements from any other group. Most interhalogen compounds...
second rarest naturally occurring element (after astatine). Francium's isotopes decay quickly into astatine, radium, and radon. The electronic structure of...
chlorine (Cl), bromine (Br), iodine (I), and the radioactive elements astatine (At) and tennessine (Ts), though some authors would exclude tennessine...
1019 years, polonium, astatine, and radon are some of the shortest-lived and rarest elements known; less than a gram of astatine is estimated to exist...
physicists Emilio G. Segrè, who discovered the elements technetium and astatine, and the antiproton); Bruno Rossi, a pioneer in Cosmic Rays and X-ray astronomy;...
bismuth due to the short half-lives of the next two elements, polonium and astatine, which decay to bismuth or lead. The r-process is so fast it can skip this...
Astatine iodide is an interhalogen compound with the chemical formula AtI. It is the second heaviest known interhalogen compound, after iodine tribromide...
Ataxia–telangiectasia, an immunodeficiency disorder Athletic training Atrial tachycardia Astatine (symbol At), a chemical element Ampere-turn (symbol A t), an International...
Astatine bromide is an interhalogen compound with the chemical formula AtBr. Astatine bromide is produced by the reaction of astatine with an aqueous...
benchmark, although it is not a metal. Borderline germanium, antimony, and astatine have been included. Some other elements in the middle of the 4d and 5d...
compound of sodium and astatine with the chemical formula NaAt. Sodium astatide solution has been prepared by distilling astatine from the bismuth alpha-ray...
tetrahalides with all halogens except astatine and forms dihalides with all halogens except bromine and astatine. Germanium bonds to all natural single...
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