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Responsible Investment in Mining and Exploration Stocks

Geology and ESG Research Analysis




Metals are part of our modern lives and we must think sustainability through a process: Extraction-Integration-Recycling.






Atomic number






Occurrence / Extraction

does not occur naturally, can be formed in nature as a product of spontaneous fission of uranium-238 and alpha decay of europium-151. Only trace amounts can be found in naturally occurring ores: a sample of pitchblende has been found to contain promethium at a concentration of four parts per quintillion (1018) by mass. It has been observed, however, in the spectra of some stars in the galaxy of Andromeda.


Most promethium is used for research purpose. It can be used as beta radiation source in luminous paint, in nuclear batteries for guided missiles, watches, pacemakers and rados, and as a light source for signals. It is possible that in future it will be used as portable X-ray source; and as auxiliary heat or power sources for space probes and satellites (although the alpha emitter plutonium-238 has become standard for most space-exploration).


Promethium is a rare-earth metal that emits beta radius. It does not emit gamma rays, but beta particles impinging on elements of high atomic numbers can generate X-rays, and a sample of 145Pm does produce some such soft X-ray radiation in addition to beta particles.  Promethium salts have a pink or red colour that coluors the surroundings air with a pale blue-green light.

 Atomic mass: (147) g.mol -1
 Electronegativity according to Pauling:  unknown
 Density:  6.475 at 20°C
Melting point:  about 1080 °C
Boiling point:  2460 °C
Named after Prometheus in Greek mythology, who stole fire from the gods.

Relative abundance

Promethium has never been found in the Earth's crust. It has been observed, however, in the spectra of some stars in the galaxy of Andromeda.

atomic mass (g.mol -1)


density (g/cm3)


Oxydation number


Melting point (°C)


Boiling point (°C)


Magnetic moment


Abundance in the Earth's crust ( ppm)



Jacob Akiba Marinsky, Lawrence Elgin Glendenin, and Charles DuBois Coryell  in 1947.