Francium Reference Libraries

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2009-07-10 12:54:52

Cesium (or Caesium) is a chemical element with the symbol Cs and atomic number 55. Caesium is a soft alkali metal that is silvery-gold. It melts and liquefies at 83 degrees Fahrenheit and is one of only five metals that are liquid close to room temperature. Caesium is a metal that is most widely known for its use in atomic clocks. Cesium comes from the Latin word caesius meaning...

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
  • A person in a secondary role, specifically the second most important character (after the protagonist).
The word 'deuteragonist' comes from a Greek word meaning 'an actor of second-class parts'.