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Element 72 - Hafnium (Hf) sound

From Hafnia, the Latin name for Copenhagen; discovered 1923. A "wonder metal" of the atomic age, hafnium has a great appetite for neutrons. Thus it goes into neutron-absorbing reactor control rods which slow down nuclear chain reactions and also quench atomic "fires."

Properties

Atomic Number: 72
Atomic Weight: 178.49
Electron Configuration (at ground state): 1s22s22p63s23p63d104s24p64d104f145s25p65d26s2
Oxidation States (Bold most stable): +4
Boiling Point (K): 4875
Melting Point (K): 2504
Density (at 300K -- g/cm3): 13.31
Atomic Volume (at 300K -- cm3/mol) 13.6
Number of stable isotopes: 6
Covalent Radius (Å): 1.44
Atomic Radius (Å): 1.67
First Ionization Potential (V): 6.65
Electronegativity (Pauling's): 1.3
Specific Heat Capacity (at 300K -- J g-1 K-1): 0.14
Heat of Vaporization (kJ/mol): 661.07
Heat of Fusion (kJ/mol): 21.76
Electrical Conductivity (at 293K for polycrystalline material -- 106 (ohms)-1 cm-1): 3.4
Thermal Conductivity (at 300K -- W m-1 K-1): 23.0
Crystal Structure: Hexagonal
Acid-Base Properties: Amphoteric