Molybdenum

1778,1781 Molybdenum

The book of science

Tom Sharp

UppsalaCarl Wilhelm Scheele, Peter Jacob Hjelm elements Molybdenum

Molybdenum

The common ore of molybdenum, its disulfide, was known for centuries as molybdena, confused with lead ore, and used as though it were graphite. Bengt Andersson Qvist, however, distinguished it from lead ore in 1754. In 1778, Carl Wilhelm Scheele reduced the ore to its oxide and determined that it was a new element, which he named molybdenum. At Scheele’s suggestion, Peter Jacob Hjelm reduced Scheele’s oxide with carbon and linseed oil to produce molybdenum metal in 1781.

Atomic number 42

Molybdenum (accent on the third syllable) is a silver-gray metal with a high melting point that makes strong alloys with steel. Molybdenum is an essential trace element, having a role in critical enzymes for animals and in enzymes that fix nitrogen for some bacteria. Molybdenum is used an industrial catalyst, as an additive in lubricating oils, and as molybdenum disulfide for solid lubricants. Molybdenum is used in corrosion-resistant pigments, smoke-resistant plastics for wire insulation, and as molybdenum disilicide in high-temperature ceramics.

Light and strong

Almost half the weight of tungsten, molybdenum replaced tungsten in some steels in World War I. In 1923 Wills Sainte Claire was advertised as “The All Mo-lyb-den-um Car.”

I had always placed the accent on the second syllable, but now I must try to put it on the third. Diamond used to be the hardest form of carbon; now, the honors go to carbyne, or fullerite, or Q-carbon.

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