Symbol Pm Atomic radius: pm 181 Fusion: kJ/Mole 7.7
Name Promethium Ionic radius: pm (+3)109 Boiling point: C 3000
Atomic number 61 Electron affinity - Melting point: C 1042
Atomic weight 145.0 1st  ion potential 5.55 Specific Heat Cap: J/(g K) -
Classification Trans metal Natural form Solid Thermal Cond: W/(cm K) 0.15
Configuration [Xe]4f56s2 Crystal structure Hex Electrical Cond -
Oxidation states 3 Density 7.26 Abundance: mg/kg-crust <0.001
Electronegativity - Vaporization: kJ/Mole -    
Proof of the existence of promethium was obtained in 1947 by J.A. Marinsky, L.E. Glendenin, and C.D. Coryell who isolated radioactive isotope promethium-147 from uranium fission products. Uses - nuclear battery, convert light to electrical current, thickness gauges