caesium
 銫[金屬元素]


 cae·si·um /ˈsɪzɪəm/ 名詞
 銫


 caesium, Cæ·si·um n.  Chem. A rare alkaline metal found in mineral water; -- so called from the two characteristic blue lines in its spectrum. It was the first element discovered by spectrum analysis, and is the most strongly basic and electro-positive substance known. Symbol Cs.  Atomic number 55.  Atomic weight 132.6.
 Syn: -- cesium, Cs

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 caesium
      n : a soft silver-white ductile metallic element (liquid at
          normal temperatures); the most electropositive and
          alkaline metal [syn: cesium, Cs, atomic number 55]


 caesium
 Symbol: Cs
 Atomic number: 55
 Atomic weight: 132.90545
 Soft silvery-white metallic element belonging to group 1 of the periodic
 table. One of the three metals which are liquid at room temperature. Cs-133
 is the natural, and only stable, isotope. Fifteen other radioisotopes exist.
 Caesium reacts explosively with cold water, and ice at temperatures above
 157K. Caesium hydroxide is the strongest base known. Caesium is the most
 electropositive, most alkaline and has the least ionization potential of
 all the elements. Known uses include the basis of atomic clocks, catalyst
 for the hydrogenation of some organic compounds, and in photoelectric cells.
 Caesium was discovered by Gustav Kirchoff and Robert Bunsen in Germany in
 1860 spectroscopically. Its identification was based upon the bright blue
 lines in its spectrum. The name comes from the latin word caesius, which
 means sky blue. Caesium should be considered highly toxic. Some of the
 radioisotopes are even more toxic.