molybdenum

American  

[muh-lib-duh-nuhm] / məˈlɪb də nəm /

noun

Chemistry.

1. a silver-white metallic element, used as an alloy with iron in making hard, high-speed cutting tools. Mo; 95.94; 42; 10.2.

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molybdenum British  

/ mɒˈlɪbdɪnəm /

noun

1. a very hard ductile silvery-white metallic element occurring principally in molybdenite: used mainly in alloys, esp to harden and strengthen steels. Symbol: Mo; atomic no: 42; atomic wt: 95.94; valency: 2–6; relative density: 10.22; melting pt: 2623°C; boiling pt: 4639°C

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molybdenum Scientific  

/ mə-lĭb′də-nəm /

1. A hard, silvery-white metallic element that resists corrosion and retains its strength at high temperatures. It is used to harden and toughen steel and to make high-temperature wiring. Molybdenum is an essential trace element in plant metabolism. Atomic number 42; atomic weight 95.96; melting point 2,623°C; boiling point 4,639°C; specific gravity 10.22 (at 20°C); valence 2, 3, 4, 5, 6.

2. See Periodic Table

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Etymology

Origin of molybdenum

First recorded in 1790–1800; from New Latin molybdēnum, alteration of earlier molybdēna “lead ore,” from Latin molybdaena, from Greek molýbdaina “galena,” equivalent to mólybd(os) “lead” + -aina a suffix indicating relationship or origin

Example Sentences

The challenge is achieving enough energy to remove sulfur atoms from the top layer without harming the molybdenum layer beneath.

From Science Daily • Jun. 17, 2026

The company is targeting 3.1 billion pounds of copper, 650,000 ounces of gold, and 90 million pounds of molybdenum for 2026.

From Barron's • Apr. 23, 2026

To accomplish this, the researchers worked with a carefully engineered material made of two atomically thin layers of the organic semiconductor molybdenum ditelluride.

From Science Daily • Mar. 3, 2026

Other companies with recently issued exploitation permits include an anorthosite mining project backed by investors from Denmark and Luxembourg, and a molybdenum project backed by the European Union and run by Canadian company Greenland Resources.

From Barron's • Feb. 14, 2026

A poor pharmacist with little in the way of advanced apparatus, he discovered eight elements–chlorine, fluorine, manganese, barium, molybdenum, tungsten, nitrogen, and oxygen–and got credit for none of them.

From "A Short History of Nearly Everything" by Bill Bryson