as·ta·tine /ˈæstəˌtin/
 石厄


 as·ta·tine /ˈæstəˌtɪn/ 名詞



 astatine
      n : a highly unstable radioactive element (the heaviest of the
          halogen series); a decay product of uranium and thorium
          [syn: At, atomic number 85]


 astatine
 Symbol: At
 Atomic number: 85
 Atomic weight: (210)
 Radioactive halogen element. Occurs naturally from uranium and thorium
 decay. At least 20 known isotopes. At-210, the most stable, has a
 half-life of 8.3 hours. Synthesized by nuclear bombardment in 1940 by D.R.
 Corson, K.R. MacKenzie and E. Segre at the University of California.