Definition of "polonium" [po•lo•ni•um]

• A naturally radioactive metallic element, occurring in minute quantities as a product of radium disintegration and produced by bombarding bismuth or lead with neutrons. It has 27 isotopes ranging in mass number from 192 to 218, of which Po 210, with a half-life of 138.39 days, is the most readily available. Atomic number 84; melting point 254°C; boiling point 962°C; specific gravity 9.32; valence 2, 4. See Table at element. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "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."
• "I have now managed to get Meyer to write a letter to Curie asking to send one of our scientists, Frau Doctor Rona, chemist and specialist in polonium, to her lab for three weeks in order to learn the art from Irene Curie ..."
• "Elisabeth Rona, one of the female experimenters who worked at the institute and who specialized in polonium preparations, seemed to be one of the few who had a clear sense of how hazardous radiation could be."