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Element 42 - Molybdenum (Mo) sound

From molybdos, or lead--first found in what was thought to be lead ore; discovered 1778. Fifth highest melting metal, it is used in boiler plate, rifle barrels, and filaments. No vessel could be found in which to cast it until a special water-cooled crucible was devised in 1959.

Properties

Atomic Number: 42
Atomic Weight: 95.94
Electron Configuration (at ground state): 1s22s22p63s23p63d104s24p64d55s1
Oxidation States (Bold most stable): +2, +3, +4, +5, +6
Boiling Point (K): 4912
Melting Point (K): 2896
Density (at 300K -- g/cm3): 10.22
Atomic Volume (at 300K -- cm3/mol) 9.40
Number of stable isotopes: 7
Mass Number (Bold naturally occurring) -- Half-Life -- Disintigration Type: 99 -- 66.02 hours -- beta particle (electron) emission
Covalent Radius (Å): 1.30
Atomic Radius (Å): 1.39
First Ionization Potential (V): 7.099
Electronegativity (Pauling's): 2.16
Specific Heat Capacity (at 300K -- J g-1 K-1): 0.25
Heat of Vaporization (kJ/mol): 590.4
Heat of Fusion (kJ/mol): 36
Electrical Conductivity (at 293K for polycrystalline material -- 106 (ohms)-1 cm-1): 17.3
Thermal Conductivity (at 300K -- W m-1 K-1): 138
Crystal Structure: Cubic, body centered
Acid-Base Properties: Very acidic