Promethium was discovered by J. A. Marinsky, Lawrence Glendenin, Charles D. Coryell at 1945 in United States.
Origin of name: named after "Prometheus" in Greek mythology, who stole fire from the gods.
Atomic Number: 61
Atomic Weight: 145
Melting Point: 1315 K (1042°C or 1908°F)
Boiling Point: 3273 K (3000°C or 5432°F)
Density: 7.26 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Metal
Period Number: 6 Group Number: none Group Name: Lanthanide