Polonium

Polonium
Symbol: Po
Atomic Number: 84
Atomic Weight: 209 (most stable)
Boiling Point: ??? K
Melting Point: 527 K
Density at 300K: 9.3 g/cm³
Covalent radius: 1.53
Atomic radius: 1.53
Atomic volume: 22.70 cm³/mol
First ionization potental: 8.42 V
Specific heat capacity: ??? Jg^-1K^-1
Thermal conductivity: 20 Wm^-1K^-1
Electrical conductivity: 0.7*10⁶Ω^-1m^-1
Heat of fusion: 13 kJ/mol
Heat of vaporization: 120 kJ/mol
Electronegativity: 2.0 (Pauling's)

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(So named (Medieval Latin Polonia, Poland) in 1898 by its one of its discovers, Marie Curie, after her native land) A radioactive, nonmetallic chemical element formed naturally by the disintegration of radium or synthetically by the neutron irradiation of bismuth followed by beta decay. It is used as a power source in space satellites, as an aid in inducing electric discharges, etc.

Symbol: Po
Atomic number: 84
Atomic weight: 209 (isotope with the longest known half-life)
Density (at room temperature and pressure): 9.2 g/cc
Melting point: 254°C
Boiling point: 962°C
Main valence: +4
Ground state electron configuration: [Xe]4f¹⁴5d¹⁰6s²6p⁴

Polonium is a very rare radioactive element discovered by Mme. Curie in 1898. It also was the first element discovered by Mme. Curie. Polonium is so rare, that there are only approximately 100 micrograms of it per ton of Uranium. It is possible, however, to create very small amounts of polonium by bombarding natural Bismuth (209Bi) with neutrons. There are 25 known isotopes of polonium, with atomic masses ranging from 194 to 218. Polonium-10 is the easiest to obtain. Also, isotopes of mass 209 and 208 can be produced by alpha, proton, or deuteron bombardment of bismuth. Polonium radiation gives off alpha particles, but it is extremely dangerous, and must be handled with utmost care. Even milligrams or micrograms of polonium can have a devastating effect on human tissue.

Polonium 210

Polonium 210 (abbreviated Po 210) is a radioactive element; half-life 138.4 days. It decays to lead 206 by emmission of an alpha particle (alpha radiation). Richard Rhodes said, based upon its physical properties, " Polonium was a strange metal." The element " . . . emitted five thousand times as much radiation as an equivalent mass of radium." This intense radiation is capable of causing the surrounding air to exhibit a blueish glow (Rhodes 578-580).

Po 210 alpha particles can be stopped by a thin layer of metal foil. During the Manhattan Project Po 210 was transported on platinum foil (itself sealed in a container). For unknown reasons Po is capable of migration outside a sealed container and " . . . can quickly contaminate large areas." It has been observed to travel against an air current, move from place to place without otherwise being acted upon, embed itself " . . . in the walls of shipping containers . . . ," and was used as part of the neutron initiator in the "Fat Man" atomic bomb (Rhodes 578-580).

Works Cited

Rhodes, Richard. The Making of the Atomic Bomb. New York: Simon and Schuster, 1986.

Po*lo"ni*um (?), n. [NL. So named after Poland, in L. form Polonia, one of the discoverers being a Pole.] (Chem.)

A supposed new element, a radioactive substance discovered by M. and MMe. Curie in pitchblende. It is closely related chemically to bismuth. It emits only alpha rays and is perhaps identical with radium F.

 

© Webster 1913.