promethium (Pm)

Promethium (Pm) is a radioactive, metallic element of the lanthanide series. It was first made in 1941 by particle bombardment of neodymium and praseodymium. Promethium occurs in uranium ores in minute amounts. The isotope 147Pm is used in phosphorescent paints, X-ray tubes, and in nuclear-powered batteries for space vehicles. The most stable isotope is 145Pm (half-life 17.7 years).


atomic number 61
melting point 1,080°C (1,976°F)
boiling point 2,460°C (4,460°F)