Crossword clues for astatine
astatine
Douglas Harper's Etymology Dictionary
Wiktionary
n. A highly radioactive chemical element (''symbol'' At), one of the halogens, with atomic number 85.
WordNet
n. a highly unstable radioactive element (the heaviest of the halogen series); a decay product of uranium and thorium [syn: At, atomic number 85]
Wikipedia
Astatine is a radioactive chemical element with the chemical symbol At and atomic number 85, and is the rarest naturally occurring element on the Earth's crust. It occurs on Earth as the decay product of various heavier elements. All its isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours. Elemental astatine has never been viewed because any macroscopic sample would be immediately vaporized by its radioactive heating. It has yet to be determined if this obstacle could be overcome with sufficient cooling.
The bulk properties of astatine are not known with any certainty. Many of these have been estimated based on its periodic table position as a heavier analog of iodine, and a member of the halogens – the group of elements including fluorine, chlorine, bromine, and iodine. It is likely to have a dark or lustrous appearance and may be a semiconductor or possibly a metal; it probably has a higher melting point than that of iodine. Chemically, several anionic species of astatine are known and most of its compounds resemble those of iodine. It also shows some metallic behavior, including being able to form a stable monatomic cation in aqueous solution (unlike the lighter halogens).
Dale R. Corson, Kenneth Ross MacKenzie, and Emilio G. Segrè synthesized the element at the University of California, Berkeley in 1940, naming it after the Greek astatos (ἄστατος), "unstable". Four isotopes of astatine were subsequently found in nature, although it is the least abundant of all the naturally occurring elements, with much less than one gram being present at any given time in the Earth's crust. Neither the most stable isotope astatine-210 nor the medically useful astatine-211 occurs naturally. They can only be produced synthetically, usually by bombarding bismuth-209 with alpha particles.
Usage examples of "astatine".
We link the astatine isotope to carrier molecules that seek out the disseminated microscopic cancers in your brain.
When Ohm had only a few human robots he got enough astatine from his own banknotes.
Their entire project depends on that astatine to keep the robots going and to create more stalk ears.
The Treasury Department will never believe in this story of biocontrol, alien plants, astatine, and human robots.
With the astatine supply at stake any Queensbury Rules followed before would now be ignored.
The nobles also renounced him and elected his cousin Stron Astatine as their new king.
Lady Astatine was the only relative who retained critical objectivity.
The isotope of astatine had a half-life of eight hours-yet, impossibly, it was stable.
After that it becomes astatine for three ten-thousandths of a second, and bismuth for an hour, and polonium 212 for three ten-millionths of a second.
No one had ever handled anything as high as astatine before, and there were eighty-five of the little buggers to worry about.