Promethium

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

Explanatory Notes

mp = 1080 deg C; [Merck Index]

Reference Link #2

Other Information

No other related information on this agent was found.