Back to Periodic Table
84Po209 u

Polonium

metalloid
Atomic Number
84
Atomic Mass
209 u
Period
6
Group
16

Quick Facts

PropertyValue
SymbolPo
Atomic Number84
Atomic Mass[209] u
CategoryMetalloid
Period6
Group16
Blockp
Electron Configuration[Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁴

Physical Properties

PropertyValue
State at 20°CSolid
Density9.20 g/cm³
Melting Point254°C (527 K)
Boiling Point962°C (1235 K)
AppearanceSilvery metal

History and Discovery

Discovered by: Marie and Pierre Curie Year of Discovery: 1898 Location: Paris, France

Etymology

Named after Poland, Marie Curie's homeland.

Applications and Uses

  • Static eliminators (Po-210, declining use)
  • Neutron sources (with beryllium)
  • Heat source for satellites (thermoelectric generators)
  • Historically used in spark plugs

Toxicity

Polonium-210 is extremely toxic. A microgram is lethal. Used in the assassination of Alexander Litvinenko (2006).

Interesting Facts

  1. First element discovered by Marie Curie
  2. One of the most radioactive natural elements
  3. Generates significant heat from radioactive decay
  4. Infamously used as a poison
  5. Named to draw attention to Poland's lack of independence