Atomic number:61

Group numbers:3

Period:6

Electronic configuration:[Xe] 4f⁵ 6s²

Formal oxidation number:+3

Electronegativities:-

Atomic radius / pm:183.4

Relative atomic mass:[145]

 

Promethium was discovered by Jacob Akiba Marinsky, Lawrence Elgin Glendenin, and Charles DuBois Coryell (US) in 1947. Named after Prometheus in Greek mythology, who stole fire from the gods. It is a rare earth metal of synthetic origin on the earth, naturally made in stars. It is Poisonous, radiotoxic and radioactive. Promethium does not occur naturally. It is found among fission products of uranium, thorium and plutonium. It has been used as a source of radioactivity for thickness-measuring gages.

Density / g dm^-3:7220 (298 K)

Molar volume / cm³mol^-1:20.08 (298 K)

Electrical resistivity / μΩcm:- (20 °C)

Thermal conductivity / W m^-1K^-1:17.9

Melting point / °C:1042

Boiling point / °C:3000

Heat of fusion / kJ mol^-1:12.6

Heat of vaporization / kJ mol^-1:-

Heat of atomization / kJ mol^-1:308

1st ionization energy / kJ mol^-1:538.39

2nd ionization energy / kJ mol^-1:1051.70

3rd ionization energy / kJ mol^-1:2151.64

in the atmosphere / ppm:-

in the Earth's crust / ppm:-

in the oceans / ppm:-