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]

The Collaborative International Dictionary of English. 2000.

Look at other dictionaries:

  • Polonium — (] [cite journal author = Momoshima N., Song L.X., Osaki S.,Maeda Y., title = Biologically induced Po emission from fresh water journal =J Environ Radioact. year = 2002 volume = 63 issue = 2 pages = 187–197 doi =10.1016/S0265 931X(02)00028 0]… …   Wikipedia

  • POLONIUM — Le polonium (symbole Po, numéro atomique 84) est un élément radioactif découvert par Pierre et Marie Curie, en 1898, dans la pechblende de Joachimsthal. Ayant observé que la radioactivité des minerais d’uranium était supérieure à celle que l’on… …   Encyclopédie Universelle

  • Polonium — Bismuth ← Polonium → Astate Te …   Wikipédia en Français

  • Polonĭum — Polonĭum, ein in Pechblende enthaltenes Metall, das aus Wismutpoloniumlösung durch Eintauchen von Wismut als äußerst aktive Schicht (4 mg aus 2000 kg Pechblende) erhalten wird; es ist ähnlich dem Wismut. Vgl. Radioaktivität …   Meyers Großes Konversations-Lexikon

  • Polonium — Polonĭum, vom Ehepaar Curie 1898 im Uranpecherz aufgefundenes, stark radioaktives chem. Element. Seine Existenz ist neuerdings wieder zweifelhaft geworden …   Kleines Konversations-Lexikon

  • polonium — POLÓNIUM s.n. v. poloniu. Trimis de LauraGellner, 13.09.2007. Sursa: DN …   Dicționar Român

  • 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… …   Elements of periodic system

  • polonium — radioactive element, discovered 1898 by Marie Curie and her husband and named for her native country, POLAND (Cf. Poland) (Modern Latin Polonia) …   Etymology dictionary

  • polonium — [pə lō′nē əm] n. [ModL: so named (1898) by its co discoverer CURIE Marie, after her native land, Poland (ML Polonia) + IUM] a radioactive, nonmetallic chemical element formed naturally by the disintegration of radium or synthetically by the… …   English World dictionary

  • Polonium — Eigenschaften …   Deutsch Wikipedia

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