Molybdenum
Definition and meaning of Molybdenum in chemistry.
Molybdenum is a silvery-white, very hard transition metal characterized by the chemical symbol Mo and an atomic number of 42. It possesses one of the highest melting points of all pure elements, making it critical for high-temperature metallurgical applications and advanced structural materials.
In more detail
Situated in group 6 and period 5 of the periodic table, molybdenum does not occur naturally as a free metal on Earth but is found in various oxidation states within minerals like molybdenite (MoS2) and wulfenite. The element readily forms hard, stable carbides in solid solution with iron, which is why the vast majority of the world production is used in specialized steel alloys, including high-strength alloys and aerospace superalloys. Molybdenum serves a biologically essential role in many organisms as a trace dietary element, functioning as a vital cofactor in several enzymes such as nitrogenase, nitrate reductase, and sulfite oxidase. Chemically, it exhibits multiple oxidation states spanning from -2 to +6, resisting attack by hydrochloric acid or hydrofluoric acid but dissolving slowly in hot oxidizing acids. At temperatures exceeding 600 degrees Celsius, the bulk metal oxidizes rapidly to form volatile molybdenum trioxide, dictating that high-temperature processing must occur in inert environments or under strict vacuum conditions.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Mo |
| Atomic number | 42 |
| Atomic mass | 95.95 u |
| Category | Transition Metal |
| State at room temperature | Solid |
| Melting point | 2623 °C |
| Boiling point | 4639 °C |
| Year discovered | 1778 |
Molybdenum disulfide is heavily used as a solid dry lubricant in high-temperature or high-vacuum mechanical environments where typical petroleum-based greases would break down or instantly vaporize.
Frequently asked questions
Why is molybdenum added to steel?
It substantially increases strength, electrical conductivity, and resistance to corrosion and wear, which is vital for structural steel, armor plate, and aircraft parts.
How does molybdenum function in the human body?
Molybdenum acts as a critical cofactor for several crucial enzymes involved in breaking down amino acids and metabolizing various drugs and toxins.