Astatine is a very rare radioactive chemical element with the chemical symbol At and atomic number 85. It occurs on Earth as the decay product of various heavier elements. All its isotopes are short-lived, with half-lives of 8.1 hours or less. Elemental astatine has never been viewed because a mass large enough to be seen by the naked eye would be immediately vaporized by its radioactive heating. The bulk properties of astatine are not known with any certainty, but they have been predicted based on its similarity to the other halogens, the lighter elements directly above it in the periodic table: fluorine, chlorine, bromine and especially iodine. It is likely to have a dark or lustrous appearance and may be a semiconductor or possibly a metal; it will probably have a higher melting point than 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 the ability to form a stable monatomic cation in aqueous solution (unlike the lighter halogens).
Read more: https://en.wikipedia.org/wiki/Astatine
_______________________________ Today's selected anniversaries:
1658:
Anglo-Spanish War: English colonial forces repelled a Spanish attack in the largest battle ever fought on Jamaica. https://en.wikipedia.org/wiki/Battle_of_Rio_Nuevo
1910:
The Firebird, the first major work by Russian composer Igor Stravinsky, made its premiere in Paris. https://en.wikipedia.org/wiki/The_Firebird
1950:
The Korean War began with North Korean forces launching a pre- dawn raid over the 38th parallel into South Korea. https://en.wikipedia.org/wiki/Korean_War
1975:
Citing threats to national security, Indian Prime Minister Indira Gandhi unilaterally had a state of emergency declared across the nation that lasted nearly two years. https://en.wikipedia.org/wiki/The_Emergency_(India)
2013:
Tamim bin Hamad Al Thani became the eighth Emir of Qatar, currently the world's youngest reigning monarch. https://en.wikipedia.org/wiki/Tamim_bin_Hamad_Al_Thani
_____________________________ Wiktionary's word of the day:
flense: To strip the blubber or skin from, as from a whale, seal, etc. https://en.wiktionary.org/wiki/flense
___________________________ Wikiquote quote of the day:
I applied my reason at every moment. Reason is excellent for getting food, clothing and shelter. Reason is the very best tool kit. Nothing beats reason for keeping tigers away. But be excessively reasonable and you risk throwing out the universe with the bathwater. --Yann Martel https://en.wikiquote.org/wiki/Yann_Martel