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Element 59 - Praseodymium (Pr) sound

From prasios didymos, or green twin (from its green salts); discovered 1885 when separated from its rare-earth twin neodymium. Together, they are now used in making lenses for glassmaker's goggles because they filter out the yellow light present in glass blowing.

Properties

Atomic Number: 59
Atomic Weight: 140.9077
Electron Configuration (at ground state): 1s22s22p63s23p63d104s24p64d104f35s25p66s2
Oxidation States (Bold most stable): +3, +4
Boiling Point (K): 3785
Melting Point (K): 1204
Density (at 300K -- g/cm3): 6.77
Atomic Volume (at 300K -- cm3/mol) 20.8
Number of stable isotopes: 1
Mass Number (Bold naturally occurring) -- Half-Life -- Disintigration Type: 142 -- 19.1 hours -- beta particle (electron) emission
Covalent Radius (Å): 1.65
Atomic Radius (Å): 1.82
First Ionization Potential (V): 5.42
Electronegativity (Pauling's): 1.13
Specific Heat Capacity (at 300K -- J g-1 K-1): 0.193
Heat of Vaporization (kJ/mol): 332.63
Heat of Fusion (kJ/mol): 10.04
Electrical Conductivity (at 293K for polycrystalline material -- 106 (ohms)-1 cm-1): 1.5
Thermal Conductivity (at 300K -- W m-1 K-1): 12.5
Crystal Structure: Hexagonal
Acid-Base Properties: Very basic