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Promethium (Pm): Fun Facts and Information About the Element


What is the symbol? Pm
What is the atomic number? 61
What is the atomic weight? 145
What is the melting point in Celsius? 1100
What is the boiling point in Celsius? 3000
What is the density (g/cm3)? 7.3
What year was it discovered? 1945
Who discovered the element? “Jacob A. Marinsky, Lawrence E. Glendenin, and Charles D. Coryell”
What group is the element in? 101
What is the electron configuration? [Xe] 4f5 6s2
What is the ionization energy? 5.582
What element category is it in? Lanthanoids

Where is Promethium Found?

Searches for the element on earth have been fruitless, and it now appears that promethium is completely missing from the earth’s crust. Promethium, however, has been identified in the spectrum of the star HR465 in Andromeda. This element is being formed recently near the star’s surface, for no known isotope of promethium has a half-life longer than 17.7 years.

What is Promethium Used For?

The element has applications as a beta source for thickness gages, and it can be absorbed by a phosphor to produce light. Promethium shows promise as a portable X-ray source, and it may become useful as a heat source to provide auxiliary power for space probes and satellites. More than 30 promethium compounds have been prepared. Most are colored.