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All 118 elements

Element 42 ·transition metal

mù — "molybdenum"

Molybdenum

Traditional:

How the character is built

The radical marks this as a metal, and that is not a coincidence of this one character — it holds right across the table. Read the radical first and the element's state at room temperature is already settled. It is (jīn) squeezed into the space beside another component — radicals change shape by position, which is why is hard to spot until you know to look for .

This character is used for the element and little else — you are unlikely to meet it outside a chemistry classroom.

The element itself

Molybdenite is soft, grey, greasy and will mark paper, which is exactly why it was confused for centuries with both graphite and lead ore — the name comes from the Greek word for lead, applied to anything that left a dark streak. Once separated, molybdenum turned out to have one of the highest melting points of any metal and to make steel enormously tougher, which took it from curiosity to strategic material within a generation. Most of it is scraped out of porphyry copper mines as a by-product, though a few deposits are rich enough to be worked for molybdenum alone.

Where it sits among the 118

Molybdenum melts at 2623°C (2896 K) — lower than 4 of the 97 elements whose melting point has been measured, and higher than 92. The grey dots are the rest of the table.
In the Earth's crust there is about 1.2 grams in every tonne of rock. That makes it commoner than 34 of the 93 elements that occur naturally at all. The scale is logarithmic: each gridline is ten times the one below it.

First isolated in 1781.

In living things

Molybdenum is the one heavy transition metal that life uses widely, and the reason is oceanographic: as molybdate it is soluble and unreactive, making it the most abundant transition metal in modern seawater, whereas iron rusts out of solution. Its showpiece is the iron–molybdenum cofactor of nitrogenase, the cluster that breaks atmospheric nitrogen. In our own cells it arrives on a cofactor called molybdopterin and runs sulfite oxidase and xanthine oxidase — enzymes that dispose of sulfur and purine waste, which is why an element present in milligram quantities is nonetheless indispensable.

Where it comes from in China

Molybdenum in China comes from the porphyry belt of the East Qinling mountains — Luanchuan in Henan and Jinduicheng in Shaanxi. A porphyry deposit forms when a shallow granite body cools, boils off its water and shatters its own roof, leaving a dense stockwork of hairline veinlets plated with molybdenite. The metal is spread thinly through an enormous volume of rock, which is why such mines are vast open pits rather than tunnels chasing a seam.

Shaanxi 陕西Henan 河南
Henan and Shaanxi — shaded on a map drawn from Natural Earth's public-domain data.

The full entry

For stroke order, example sentences, audio and the complete set of meanings, see the dictionary entry.

Molybdenum in the dictionary →

Others built the same way

Every one of these carries , and every one is a metal.

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