Molybdenum is a transition metal. Pure molybdenum is silvery white, very hard, but is softer and more ductile than tungsten. It has a high elastic modulus, and has one of the highest melting points of all pure elements. Only tungsten and tantalum, of the more readily available metals, have higher melting points. It is a valuable alloying agent, as it contributes to the hardenability and toughness of quenched and tempered steels. It also improves the strength of steel at high temperatures. Molybdenum is important in plant nutrition, and is found in certain enzymes.

• High boiling point (4,639°C, 8,382°F)
• High melting point (2,623°C, 4,753°F)
• Resistance to corrosion
• Good machinability
• Low vapor pressure
• Excellent thermal expansion

Molybdenum has many valuable properties in hot strength, creep resistance, wear resistance, machinability, corrosion resistance, low vapor pressure, conductivity, low friction and so on. While it’s tempting to believe that applications are controlled by a single property, many molybdenum applications exist truly because of a useful combination of several properties. For instance, hotstrength is a critical property for high-temperature tooling like casting die inserts, but molybdenum’s high resistance to failure by thermal shock and thermal fatigue equally important. These qualities relate to molybdenum’s unique combination of low heat capacity and high thermal conductivity, which minimizes thermal stresses.