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Praseodymium Facts

Chemical & Physical Properties

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This is a picture of a chunk of pure praseodymium metal under a protective argon atmosphere.

This is a picture of a chunk of pure praseodymium metal under a protective argon atmosphere. Praseodymium is a soft silvery metal that develops a green oxide coating that spalls off when exposed to air.

Tomihahndorf, Free Documentation License
Periodic Table of the Elements

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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