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Promethium [Pm]
CAS-ID: 7440-12-2
An: 61 N: 84
Am: [145] g/mol
Group Name: Lanthanoids
Block: f-block   Period: 6 (lanthanoid)
State: solid at 298 K
Colour: metallic Classification: Metallic
Boiling Point: 3273K (3000°C)
Melting Point: 1373K (1100°C)
Density: 7.26g/cm3
Discovery Information
Who: J.A. Marinsky, L.E. Glendenin, C.D. Coryell
When: 1945
Where: United States
Name Origin
From Prometheus who stole the fire of the sky and gave it to mankind.
 "Promethium" in different languages.
Sources
Does not occur naturally. Found among fission products of uranium, thorium, and plutonium.
Uses
Used as a radiation source in thickness gauges, photoelectric cells and hold potential as a heat source for auxiliary power in satellites. In a nuclear battery in which photocells convert the light into electric current, yielding a useful life of about five years using 147Pm.
History
The existence of promethium was first predicted by Bohuslav Brauner in 1902; this prediction was supported by Henry Moseley in 1914, who found a gap for a missing element which would have atomic number 61, but was unknown (however, Moseley of course had no sample of the element to verify this). Several groups claimed to have produced the element, but they could not confirm their discoveries because of the difficulty of separating promethium from other elements. Promethium was first produced and proved to exist at Oak Ridge National Laboratory (ORNL) in 1945 by Jacob A. Marinsky, Lawrence E. Glendenin and Charles D. Coryell by separation and analysis of the fission products of uranium fuel irradiated in the Graphite Reactor; however, being too busy with defense-related research during World War II, they did not announce their discovery until 1947. The name promethium is derived from Prometheus in Greek mythology, who stole the fire of the sky and gave it to mankind. The name was suggested by Grace Mary Coryell, Charles Coryell's wife, who felt that they were stealing fire from the gods.
In 1963, ion-exchange methods were used at ORNL to prepare about 10 grams of promethium from nuclear reactor fuel processing wastes.
Today, promethium is still recovered from the byproducts of uranium fission; it can also be produced by bombarding 146Nd with neutrons, turning it into 147Nd which decays into 147Pm through beta decay with a half-life of 11 days.
Notes
Promethium is also the name of a fictional element in the DC Universe; writer Marv Wolfman claims to have been unaware of the existence of a real substance by that name at the time he wrote the original script featuring the name.
Hazards
Promethium must be handled with great care because of its high radioactivity.
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