Astatine is a very rare radioactive chemical element with the chemical symbol At and the atomic number 85. It occurs on Earth as the decay product of heavier elements. All its isotopes are short-lived, with half-lives of 8.1 hours or less. The element has never been viewed because a mass large enough to be seen would be immediately vaporized by the heat of its radioactivity. The bulk properties of astatine are not known with any certainty, but they have been predicted based on its similarity to the lighter halogens directly above it in the periodic table: fluorine, chlorine, bromine and especially iodine. It is likely to appear dark or lustrous and may be a semiconductor or a metal. Chemically, several anionic species of astatine are known and most of its compounds resemble those of iodine. It also shows some metallic behavior, and may be able 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:

1844:

Felix Mendelssohn completed the score of the Violin Concerto, his final concerto. https://en.wikipedia.org/wiki/Violin_Concerto_%28Mendelssohn%29

1963:

Malaysia was formed as an independent nation from the Federation of Malaya, the Colony of Singapore, the Crown Colony of North Borneo, and the Crown Colony of Sarawak. https://en.wikipedia.org/wiki/Malaysia

1979:

Eight people escaped from East Germany to West Germany in a home-made hot air balloon. https://en.wikipedia.org/wiki/East_German_balloon_escape

1990:

Construction of the Northern Xinjiang railway (terminus pictured) was completed between Ürümqi South and Alashankou, linking the railway lines of China and Kazakhstan and adding a sizeable portion to the Eurasian Land Bridge. https://en.wikipedia.org/wiki/Eurasian_Land_Bridge

_____________________________ Wiktionary's word of the day:

liken: 1. (transitive) 2. Followed by to or (archaic) unto: to regard or state that (someone or something) is like another person or thing; to compare. 3. (also reflexive, rare) Chiefly followed by to: to make (oneself, someone, or something) resemble another person or thing. 4. (rare) To represent or symbolize (something). 5. (intransitive, obsolete) Followed by to: to be like or resemble; also, to become like. https://en.wiktionary.org/wiki/liken

___________________________ Wikiquote quote of the day:

Heart of my heart, the world is young; Love lies hidden in every rose!   --Alfred Noyes https://en.wikiquote.org/wiki/Alfred_Noyes