Astatine is a very rare radioactivechemical element with the chemical symbolAt and atomic number 85. 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 and bromine. 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).
Astatine (At) has 37 known isotopes, all of which are radioactive; the range of their mass numbers is from 191 to 229. There also exist 23 metastableexcited states. The longest-lived isotope is 210At, which has a half-life of 8.1 hours; the longest-lived isotope existing in naturally occurring decay chains is 219At with a half-life of 56 seconds.
There are 32 known isotopes of astatine, with atomic masses (mass numbers) of 191 and 193–223. No stable or even long-lived astatine isotope is known, and no such isotope is expected to exist.
Astatine has 23 nuclear isomers (nuclei with one or more nucleons– protons or neutrons– in an excited state). A nuclear isomer may also be called a "meta-state"; this means the system has more internal energy than the "ground state" (the state with the lowest possible internal energy), making the former likely to decay into the latter. There may be more than one isomer for each isotope. The most stable of them is astatine-202m1, which has a half-life of about 3minutes; this is longer than those of all ground states except those of isotopes 203–211 and 220. The least stable one is astatine-214m1; its half-life of 265ns is shorter than those of all ground states except that of astatine-213.
You can't put a butterfly in a jar If the effort's too high no matter who you are You can't catch the moon, or the sun or the stars It doesn't matter who you are Iced honey Now me I've tried a million tricks To make life cold and make it stick Not running heat that flames then out But the proud piece of ice that always floats Iced honey If I can't trap a butterfly or a bee If I can't keep my heart where I want it to be If no matter how much soul and heart I put to the wood If a flaming heart is not that good Iced honey If you can't put a butterfly in a jar If violence mars your final hour If you make others feel like jam Poured on a piece of charbroiled lamb If it's all mixed up and you cannot shout And your oxygen starts to run out If your final gasp has the recipe wrong And instead of hello you say so long If your energy starts to leak out And people wonder what you're all about A heartbreaker with an unattached heart The story of love gives them all a start And me, I've always been this way Not by choice, just this way I can't put my honey pot in a jar Or a heart or a fist of some young boy If you can't put a butterfly in a jar No wonder no need to wonder where you are It might seem like Hell, the river Styx Your affection never sticks No matter what you say, no matter what you do A butterfly heart flies right past you There's nothing to say, nothing to do See if the ice will melt for you
) ... This five-year project aims to enhance patient access to cutting-edge cancer treatments by creating a complete value chain for the production and clinical application of the alpha-emitting isotope Astatine-211 (211At) ... About Accelerate.EU ... About IBA.
Astatine is one of the least-studied elements of the periodic table, because all isotopes of astatine are unstable, with the longest half-life barely exceeding 8 hours ... One isotope, astatine-211 ...
TOKYO--(BUSINESS WIRE)--Sumitomo Heavy Industries, Ltd. invests in AlphaFusionInc., developer of Astatine based radiopharmaceuticals for Targeted Alpha Therapy... .
Renewable energy firm Astatine has raised €15m in funding to accelerate the expansion of it plans for the decarbonisation of industrial and manufacturing businesses ... Astatine identifies and implements ...
