Atomic number 74

Tungsten

W
+ phase
− phase

Shells Orbitals 4f 5d 6s

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74 electrons in 6 shells: 2, 8, 18, 32, 12, 2.

Shells are a teaching model: an electron does not travel on a ring at a fixed distance.

Category: Transition metal
Period: 6
Group: 6
Block: d
Standard atomic weight: 183.84(1) Da
Electron configuration: [Xe] 4f¹⁴ 5d⁴ 6s²
Phase at 25 °C: solid
Melting point: 3422 °C
Boiling point: 5930 °C
Density: 19.3 g/cm³
Electronegativity (Pauling): 2.36
Discovered: 1783, Juan José and Fausto Elhuyar

Neighbours in the table

Ta Re

Tungsten entered chemistry as an acid before it was a metal. In 1779 Peter Woulfe judged that wolframite held a new substance, Los Alamos records. In 1781 Carl Wilhelm Scheele drew a new acid from tungsten, then the name of the mineral now called scheelite. In 1783 the Spanish brothers Juan José and Fausto Elhuyar reduced that acid with charcoal to the metal. CIAAW, on PubChem’s record, credits the discovery to Scheele and the first isolation to the brothers, while Jefferson Lab names the brothers as discoverers.

The atom’s 74 electrons sit as [Xe] 4f¹⁴ 5d⁴ 6s². The shells run 2, 8, 18, 32, 12 and 2. The 6s pair and four 5d electrons are its six valence electrons, the ones beyond xenon’s noble-gas core. OpenStax finds heavier transition metals steadier in high oxidation states, since electrons in more distant orbitals are removed more easily. An oxidation state is the charge an atom would hold if its bonds were fully ionic. Los Alamos lists states from 6 down to −4; Jefferson Lab gives only +6.

Very pure tungsten, steel-grey to tin-white, can be cut with a hacksaw and forged, while impure metal is brittle. Los Alamos gives tungsten the highest melting point of all metals, 3422 °C in PubChem’s record. Air oxidises it, so the hot metal needs protection.

Where it is found

PubChem’s record estimates 1.25 milligrams of tungsten in a kilogram of the crust and 1 × 10⁻⁴ milligrams in a litre of seawater. It never occurs free, the Agency for Toxic Substances and Disease Registry notes in PubChem’s safety summary. The two main ores are wolframite, (Fe,Mn)WO₄, and scheelite, CaWO₄. Los Alamos places important deposits in Bolivia, Portugal, Russia and South Korea, and in California and Colorado.

Refining still follows the Elhuyar brothers’ basic method, Jefferson Lab’s account says. Crushed and cleaned ore is treated with alkali to give tungsten trioxide, WO₃. Heating the trioxide with carbon or hydrogen leaves the metal, giving off carbon dioxide or water vapour. Scrap remains an important raw material too, the US Geological Survey adds.

Natural tungsten is a mix of five isotopes: tungsten-184 is the commonest, 30.64 per cent of atoms, and tungsten-180 the rarest at 0.12 per cent. Jefferson Lab’s count of stable ones in PubChem’s record is two, and the International Atomic Energy Agency’s data there list tungsten-180 as alpha-decaying. Its half-life, the time for half its nuclei to decay, is about 1.59 × 10¹⁸ years.

Why it matters

Cemented carbide parts for cutting and wear resistance took an estimated 60 per cent of US tungsten use, the US Geological Survey reports. That share covers the United States only. Tungsten carbide, WC, is extremely hard, and Jefferson Lab’s text places it in drill-bit tips, high-speed cutting tools and mining machinery. High-speed tool steels and alloys such as Stellite and Hastelloy contain tungsten as well, Los Alamos says.

Los Alamos’s list of uses opens with filaments for electric lamps and electron tubes, then X-ray targets and heating elements for electric furnaces. The metal expands with heat about as much as borosilicate glass, which makes it useful for glass-to-metal seals. In a filament bulb, OpenStax adds, argon around the hot wire slows the tungsten’s vaporisation and lengthens the bulb’s life. Tungsten disulfide, WS₂, lubricates without oil at up to 500 °C.

Tungsten also keeps time for planetary scientists. Hafnium-182 decays to tungsten-182 with a half-life of 8.9 million years. As the early planets formed, hafnium went into silicate minerals and tungsten into metal, so the silicates gathered extra tungsten-182 from their own hafnium. IUPAC’s isotope table in PubChem’s record says the excess has helped estimate the time between the Solar System’s formation and the planets’ accretion, their growth from smaller bodies.

Properties

Properties of tungsten Standard atomic weights from IUPAC/CIAAW (abridged, 2024); other values from PubChem's periodic table, kelvin converted to °C.
Property	Value	Unit	Source
Atomic number	74
Standard atomic weight	183.84(1) Da	Da	IUPAC/CIAAW 2024
Melting point	3422 °C	°C	Los Alamos: 3422 °C
Boiling point	5930 °C	°C	Los Alamos: 5930 °C
Density	19.3 g/cm³	g/cm³
Electronegativity (Pauling)	2.36
Electron configuration	1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d⁴
Phase at 25 °C	solid

Safety

A tungsten dart, fishing weight or lamp filament is essentially harmless: the bulk metal is stable at room temperature and reacts only slowly with air and water. The cautions in PubChem’s safety summary concern finely divided powder, which is highly flammable and can ignite by itself, and dust that irritates the eyes and airways. That summary and NIOSH’s card for tungsten are the sheets for workplaces handling the powder.

Questions

Why is tungsten's symbol W?

W stands for the German wolfram, CIAAW's note on PubChem's record says. Wolfram was a material found with tin that got in the way of smelting the tin, said to eat up tin as a wolf eats sheep. The English name is Swedish, tung sten or heavy stone, and Los Alamos says it was first given around 1758 to the mineral now called scheelite.

Which metal has the highest melting point?

Tungsten, on Los Alamos's page, which also gives it the highest tensile strength of any metal above 1650 °C. PubChem's record puts the melting point at 3422 °C. OpenStax links the melting points of metals in general to how strong their metallic bonding is. PubChem's record gives a boiling point of 5555 °C and Los Alamos 5930 °C.

Is tungsten toxic?

Solid tungsten is stable at room temperature and reacts only slowly with air and water, CAMEO Chemicals says in PubChem's safety summary. Haz-Map there reports no systemic effects from workplace exposure. The European Chemicals Agency's aggregate classifies tungsten as a flammable solid that may self-heat in large quantities, though 26.5% of 741 company reports meet no hazard criterion. The International Chemical Safety Card covers the powder, highly flammable when finely divided.

Which country produces the most tungsten?

China, by a wide margin. The US Geological Survey estimates 2024 world mine output at 81,000 metric tons of tungsten, 67,000 of them from China and 3,400 from Vietnam, the next largest. Output elsewhere stayed around 20 per cent of the world total. China also holds 2.4 million of the world's more than 4.6 million tons of reserves, and the United States has mined none commercially since 2015.