Molybdenum

Symbol: Mo
Atomic Number: 42
Atomic Weight: 95.94
Element Classification: Transition Metal
Discovered By: Carl Wilhelm Scheele
Discovery Date: 1778 (Sweden)
Name Origin: Greek: molybdos (lead).
Density (g/cc): 10.22
Melting Point (K): 2890
Boiling Point (K): 4885
Appearance: Silvery white, hard metal
Atomic Radius (pm): 139
Atomic Volume (cc/mol): 9.4
Covalent Radius (pm): 130
Ionic Radius: 62 (+6e) 70 (+4e)
Specific Heat (@20C J/g mol): 0.251
Fusion Heat (kJ/mol): 28
Evaporation Heat (kJ/mol): ~590
Thermal Conductivity (@25C W/m K):
Debye Temperature (K): 380.00
Pauling Negativity Number: 2.16
First Ionizing Energy (kJ/mol): 684.8
Oxidation States: 6, 5, 4, 3, 2, 0
Electronic Configuration: [Kr] 4d5 5s1
Lattice Structure: Body-Centered Cubic (BCC)
Lattice Constant (): 3.150
Lattice C/A Ratio: n/a

Mineral Hardness [no units]: 5.5
Brinell Hardness [/MN m-2]: 1500
Vickers Hardness [/MN m-2]: 1530

Note: Molybdenum may be tough or brittle depending upon composition. It is susceptible to deformation damage in sectioning and grinding. Some alloys can be cold worked easily, although they do not work harden appreciably, so it may be difficult to get completely deformation-free microstructures. Attack-polishing additions can be made to the final polishing abrasive slurry, or vibratory polishing may be employed.

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