Praseodymium
Atomic Number: 59
Symbol: Pr
Atomic Weight: 140.90765
Element Classification: Rare Earth Element (Lanthanide Series)
Discoverer: C.F. Aver von Weisbach
Discovery Date: 1885 (Austria)
Name Origin: Greek: prasios and didymos (green twin); from its green salts
Density (g/cc): 6.773
Melting Point: 1204 K
Boiling Point: 3785 K
Appearance: silvery-white, moderately soft, malleable, ductile metal
Atomic Radius (pm): 182
Atomic Volume (cc/mol): 20.8
Covalent Radius (pm): 165
Ionic Radius: 90 (+4e) 101.3 (+3e)
Specific Heat (@20°C J/g mol): 0.192
Fusion Heat (kJ/mol): 11.3
Evaporation Heat (kJ/mol): 331
Pauling Negativity Number: 1.13
First Ionizing Energy (kJ/mol): 526.6
Oxidation States: 4, 3
Electronic Configuration: [Xe] 4f3 6s2
Lattice Structure: Hexagonal
Lattice Constant (Å): 3.670
Lattice C/A Ratio: 1.614
References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952)
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