Promethium
Atomic Number: 61
Symbol: Pm
Atomic Weight: 144.9127
Element Classification: Rare Earth Element (Lanthanide Series)
Discoverer: J.A. Marinsky, L.E. Glendenin, C.D. Coryell
Discovery Date: 1945 (United States)
Name Origin: Named for the Greek god, Prometheus
Density (g/cc): 7.2
Melting Point (K): 1441
Boiling Point (K): 3000
Covalent Radius (pm): 163
Ionic Radius: 97.9 (+3e)
Specific Heat (@20°C J/g mol): 0.185
Pauling Negativity Number: 0.0
First Ionizing Energy (kJ/mol): 536
Oxidation States: 3
Electronic Configuration: [Xe] 4f5 6s2
References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001)
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