noun. A radioactive metallic element, occurring naturally in small quantities as a product of radium disintegration and produced synthetically by bombarding bismuth or lead with neutrons. Most isotopes decay by alpha-particle emission; the most stable are Po-208 and Po-209, with half-lives of 2.9 years and 102 years, respectively. Po-210, with a half-life of 138.4 days, is the most readily available isotope and is extremely toxic. Atomic number 84; melting point 254°C; boiling point 962°C; specific gravity 9.20; valence 2, 4, 6. cross-reference: Periodic Table.

noun. A radioactive substance discovered in pitchblende by M. and Mme. Curie in 1898: named in honor of Poland, the native country Of Mme. Curie.

noun. 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.

noun. a chemical element (symbol Po) with atomic number 84.

noun. 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

"In the absence of any other option, the woman who was one of the most distinguished experts in polonium preparations eventually spent October through December of 1938 in Sweden, working on oceanography. 170 Her close friend Gleditsch offered her another temporary solution."

Poland  

eka-polonium  polane  polonium hydride  

metal  metallic element  

ammonium  harmonium  pandemonium  plutonium  zirconium  

X-ray  albumin  aripiprazole  beryllium  calomel  

radium f