Polonium

Polonium is an extremely rare and intensely radioactive element discovered by Marie and Pierre Curie in 1898. Marie Curie named it after her homeland Poland. Polonium-210 is so radioactive it can kill in microscopic amounts, it was used to assassinate former Russian spy Alexander Litvinenko in London in 2006.

  • Atomic Number8484 protons, 84 electrons
  • Atomic Mass208.98243 u84× heavier than hydrogen
  • State at Room TempSolidSolid
  • Density9.32 g/cm³
  • Melting / Boiling253.9°C / 961.9°C
  • Discovered1898

What is Polonium?

Polonium has 84 protons and no stable isotopes, it is radioactive through all of its known forms. Polonium-210, with a half-life of 138 days, is the most stable commonly encountered isotope. It is produced by bombarding bismuth-209 with neutrons in nuclear reactors.

Discovered in 1898 by Marie and Pierre Curie while processing uranium ore (pitchblende) in Paris. Marie named it after Poland, then partitioned between Russia, Germany and Austria, as an act of patriotic dedication.

Fact The assassination of Alexander Litvinenko by polonium-210 poisoning in London in 2006 was a landmark case in nuclear forensics. Polonium-210 is almost impossible to detect except with specialist radiation detectors. It was traced to meetings in hotel bars and sushi restaurants across London. British authorities concluded the Russian state was responsible, though Russia denied it.

Where you find Polonium

On Earth

Essentially no natural occurrence, any primordial polonium has decayed. Produced in nuclear reactors from bismuth-209.

How we use Polonium

  • Anti-static devices.. Polonium-210 emits alpha particles that ionise the air, neutralising static electricity in photographic film and paper processing.
  • Satellite power sources.. Polonium-210 RTGs (Radioisotope Thermoelectric Generators) powered some early Soviet spacecraft and satellites.

How it was discovered

Discovered in 1898 by Marie and Pierre Curie while processing uranium ore (pitchblende) in Paris. Marie named it after Poland, then partitioned between Russia, Germany and Austria, as an act of patriotic dedication.

Deeper dive: polonium properties

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Moving to 85 protons on the periodic table takes us to the next element.