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Hydrogen Reference Libraries

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Astatine
2009-07-09 17:47:41

Astatine is a radioactive chemical element. The symbol for Astatine is At and its atomic number is 85. Astatine is the heaviest halogen discovered. It was first produced by Dale R. Corson, Kenneth Ross Mackenzie, and Emilio Segrè in 1940. Although astatine is produced by radioactive decay in nature, it is typically found only in miniscule amounts due to its short half-life (the time it takes...

Word of the Day
bretelles
  • In dressmaking, straps running from the belt in front over the shoulders to the belt in the back, with more or less elaboration of trimming and outline. They usually broaden at the shoulder and narrow toward the waist.
The word 'bretelles' comes from a French word meaning 'braces'.