Polonium, Radioactive

Other Properties

There are 38 isotopes and isomers of polonium(1) with atomic masses ranging from 188 to 220(2) and all are radioactive(1). Polonium is a very rare natural element(1); polonium-210, -211, -212, -214, -215, -216, and -218 are members of naturally radioactive decay chains(2).

Atomic number: 84; valence: 4, occasionally 2, rarely 6; isotopes range in mass number from 193-218; all are radioactive; 210 is naturally occurring; resistivity: 42 microohm-cm at 0 deg C (alpha form), 44 microohm-cm at 0 deg C (beta form)

Low-melting, fairly volatile metal; 50% is vaporized in air in 45 hours at 55 deg C /Polonium-210/

Polonium-208: Atomic weight = 207.981231; half-life = 2.898 years; alpha decay; 5.213 MeV

Polonium-209: Atomic weight = 208.982415; half-life = 102 years; alpha decay; 4.976 MeV

Polonium-210: Atomic weight = 209.982857; half-life = 138.4 days; alpha decay; 5.407 MeV

Polonium-211: Atomic weight = 210.986637; half-life = 0.516 seconds; alpha decay; 7.594 MeV

Polonium-212: Atomic weight = 211.988852; half-life = 0.298 microseconds; alpha decay; 8.953 MeV

Polonium-214: Atomic weight = 213.995186; half-life = 163.7 microseconds; alpha decay; 7.833 MeV

Polonium-215: Atomic weight = 214.999415; half-life = 1.780 milliseconds; alpha decay; 7.526 MeV

Polonium-216: Atomic weight = 216.001905; half-life = 0.145 seconds; alpha decay; 6.906 MeV

Polonium-218: Atomic weight = 216.008965; half-life = 3.04 minutes; alpha decay; 6.114 MeV

DECAY PATHWAY: Polonium-208, half-life 2.898 years, decays via alpha emission, 5.215 MeV, to lead-204, half-life 1.4X10-17 years; decays via electron capture, 1.401 MeV, to bismuth-208, half-life 368,000 years.

DECAY PATHWAY: Polonium-209, half-life 102 years, decays via alpha emission (99.52%), 4.979 MeV, to lead-205, half-life 15,300,000 years; decays via electron capture (0.48%), 1.893 MeV, to bismuth-209, half-life stable.

DECAY PATHWAY: Polonium-210, half-life 138.376 days, decays via alpha emission,5.407 MeV, to lead-206, half-life stable.

Find more information on this substance at: Hazardous Substances Data Bank , TOXNET , PubMed