molybdeeni

Molybdeeni, commonly known as molybdenum, is a chemical element with the symbol Mo and atomic number 42. It is a silvery-gray transition metal valued for its high melting point and strength at elevated temperatures. In the periodic table it belongs to group 6 and is typically found in sulfide minerals, most notably molybdenite (MoS2).

Origin and name: The mineral molybdenite was described in the late 18th century, and the metal was isolated as a metal in 1781 by Peter Jacob Hjelm. The name molybdenum derives from the Greek molubdos, meaning lead-like, reflecting its appearance in mineral form.

Occurrence and production: Molybdenite is the principal ore. Ore deposits are mined worldwide, with major production in China, the United States, Chile and Peru. Refined molybdenum is produced by roasting to molybdenum trioxide (MoO3), then reducing to metal for use in alloys and other applications.

Applications: Molybdenum is widely used as an alloying element to improve strength, hardness and high-temperature performance of steel and other alloys. It is also used as a catalyst in petroleum refining and chemical synthesis, and molybdenum disulfide (MoS2) is employed as a solid lubricant. Molybdenum compounds are used to produce vibrant pigments.

Biological and safety: Molybdenum is an essential trace element for many organisms, required by enzymes such as xanthine oxidase, sulfite oxidase and aldehyde oxidase. Deficiency is rare in humans; excessive exposure to certain molybdenum compounds can be toxic. Environmental and occupational safety measures accompany mining and processing activities.