Polonium

3 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Polonium \Po*lo"ni*um\ (p[-o]*l[=o]"n[i^]*[u^]m), n. [NL. So
     named after Poland, in L. form Polonia, one of the
     discoverers being a Pole.] (Chem.)
     A radioactive chemical element, discovered by M. and MMe.
     Curie in pitchblende, and originally called {radium F}. It
     has atomic number 84 and an atomic weight of 210. It is a


     very rare natural element, having an abundance in uranium
     ores only 0.2% that of radium. It is closely related
     chemically to bismuth. It emits only alpha rays, and has a
     half-life of 138 days. It is thus more unstable than radium,
     and a milligram of polonium emits as many alpha particles as
     5 grams of radium. Twenty-seven isotopes are known, with
     atomic masses from 192 to 218. At present a more practical
     method of preparation than isolation from ores is the
     preparation by neutron bombardment of bismuth in a nuclear
     reactor, and it may be obtained commercially by users having
     an appropriate permit. --[HBCF61]
     [Webster 1913 Suppl. +PJC]

From WordNet (r) 2.0 [wn]:

  polonium
       n : a radioactive metallic element that is similar to tellurium
           and bismuth; occurs in uranium ores but can be produced
           by bombarding bismuth with neutrons in a nuclear reactor
           [syn: {Po}, {atomic number 84}]

From Elements database 20001107 [elements]:

  polonium
  Symbol: Po
  Atomic number: 84
  Atomic weight: (210)
  Rare radioactive metallic element, belongs to group 16 of the periodic
  table. Over 30 known isotopes exist, the most of all elements. Po-209 has
  a half-life of 103 years. Possible uses in heating spacecraft. Discovered
  by Marie Curie in 1898 in a sample of pitchblende.