Promethium

Agent Name
Promethium
CAS Number
7440-12-2; 14380-75-7 ( Pm-147)
Formula
Pm
Major Category
Physical/Radiation
Promethium formula graphical representation
Category
Radionuclides
Description
Solid metal; [Merck Index]
Sources/Uses
Promethium is present in rare earth minerals Pm-147 in minute quantities (< 10E-19 %) as a result of cosmic ray reactions and spontaneous fission of U-238. [Ullmann] Used in nuclear-powered batteries, thickness gauges, luminous compounds, and portable x-ray sources; [Merck Index] "Searches for the element on earth have been fruitless, and it now appears that promethium is completely missing from the earth's crust." [Reference #1]
Comments
All isotopes are radioactive (mass numbers = 132-155); Pm-145 has the longest half-life at 17.7 years, an alpha emitter; Present at low levels in uranium ores; [Merck Index] The stable rare earth compounds cause benign and other pneumoconioses, but Promethium is not stable. [Reference #2] Pm-147 with a half-life of 2.6 years is the most useful isotope. Pm-145 has the longest half-life; it has a specific activity of 940 Ci/g. See "Radiation, Ionizing."
Reference Link #1
Biomedical References

Exposure Assessment

Explanatory Notes
mp = 1080 deg C; [Merck Index]

Diseases, Processes, and Activities Linked to This Agent

Other Information
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