The Oxford Biblical Studies Online and Oxford Islamic Studies Online have retired. Content you previously purchased on Oxford Biblical Studies Online or Oxford Islamic Studies Online has now moved to Oxford Reference, Oxford Handbooks Online, Oxford Scholarship Online, or What Everyone Needs to Know®. For information on how to continue to view articles visit the subscriber services page.

Related Content

More Like This

Show all results sharing these subjects:

  • Science and technology
  • Chemistry


Show Summary Details



Quick Reference

Symbol Po. A rare radioactive metallic element of group 16 (formerly VIB) of the periodic table; a.n. 84; r.a.m. 210; r.d. 9.32; m.p. 254°C; b.p. 962°C. The element occurs in uranium ores to an extent of about 100 micrograms per 1000 kilograms. It has over 30 isotopes, more than any other element. The longest-lived isotope is polonium–209 (half-life 103 years). Polonium has attracted attention as a possible heat source for spacecraft as the energy released as it decays is 1.4 × 105 J kg−1 s−1. It was discovered by Marie Curie in 1898 in a sample of pitchblende.

Reference entries