fran·ci·um /ˈfræn(t)siəm/
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fran·ci·um /ˈfræn(t)sɪəm/ 名詞
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francium
n : a radioactive element of the alkali-metal group discovered
as a disintegration product of actinium [syn: Fr, atomic
number 87]
francium
Symbol: Fr
Atomic number: 87
Atomic weight: (223)
Radioactive element, belongs to group 1 of the periodic table. Found in
uranium and thorium ores. The 22 known isotopes are all radioactive, with
the most stable being Fr-223. Its existence was confirmed in 1939 by
Marguerite Perey.