Tungsten W

spore: profile
id: tungsten
spore_version: 0.2
family: refractory-metals
name: Tungsten
abbreviation: W
role: refractory metal
category: metals
type: refractory-metals
summary: |
  Tungsten is a steel-grey metal with the highest melting point of any metal, about 3,422 degC (ITIA). Its density of about 19.3 g/cm3 puts it among the heaviest metals, and its stiffness and hardness are high. Tungsten oxidises in air at high temperature and must be protected there. Most of the world's tungsten is mined in China, and in the United States about 60% of consumption goes into cemented carbide cutting and wear parts. In spaceflight-related work it has been used as rocket nozzle inserts and as a gamma-ray shield near nuclear reactors.
best_for: Very high temperature parts, dense counterweights and gamma shielding where weight per unit of shielding matters more than cost
weakest_at: Brittle and hard to form or machine; oxidises in air when hot, so it needs protection above room temperature
identity:
  formula: W
  cas: 7440-33-7
  crystal_system: body-centred cubic (bcc)
  source: we-main
  where: Crystal structure line on the WebElements main page; CAS number from PubChem CID 23964
tags:
  environments: []
  stresses: []
  applications:
    - propulsion-and-tanks
    - radiation-shielding
    - mechanisms
properties:
  - benchmark: density
    value: 19250
    unit: kg/m3
    scope: material
    conditions:
      basis: no temperature stated on the page
    method: Physical properties table, Density of solid, as printed
    status: ground
    source: we-physics
    where: Density properties section (WebElements tungsten physics page)
  - benchmark: density
    value: 19.25
    unit: g/cm3
    scope: material
    conditions:
      basis: value quoted in running text, no temperature stated
    method: Stated in the ITIA properties text
    status: ground
    source: itia
    where: Properties and intermediates page, first paragraph on tungsten properties
  - benchmark: density
    value: 19.3
    unit: g/cm3
    scope: material
    conditions:
      basis: PAC Chemical Database value at 25 degC as printed
    method: Value listed in the PubChem compound record (PAC Chemical Database entry)
    status: ground
    source: pubchem-w
    where: Density, PAC Chemical Database entry (ref 46)
  - benchmark: melting_point
    value: 3695
    unit: K
    scope: material
    conditions:
      basis: printed as 3695 K [3422 degC (6192 degF)]
    method: Key properties table on the WebElements main page
    status: ground
    source: we-main
    where: Key properties, Melting point row
  - benchmark: melting_point
    value: 3422
    unit: degC
    scope: material
    conditions:
      basis: ITIA gives 3,422 +/- 15 degC; the value here is the central figure
    method: Stated in the ITIA properties text
    status: ground
    source: itia
    where: Properties and intermediates page, first paragraph on tungsten properties
  - benchmark: boiling_point
    value: 5828
    unit: K
    scope: material
    conditions:
      basis: printed as 5828 K [5555 degC (10031 degF)]
    method: Key properties table on the WebElements main page
    status: ground
    source: we-main
    where: Key properties, Boiling point row
  - benchmark: thermal_conductivity
    value: 174
    unit: W m-1 K-1
    scope: material
    conditions:
      basis: no temperature stated on the page
    method: Physical properties table as printed
    status: ground
    source: we-physics
    where: Thermal conductivity line (WebElements tungsten physics page)
  - benchmark: cte
    value: 0.0000045
    unit: K-1
    scope: material
    conditions:
      basis: coefficient of linear thermal expansion, no temperature stated on the page
    method: Physical properties table, printed as 4.5 x 10-6 K-1
    status: ground
    source: we-physics
    where: Coefficient of linear thermal expansion line (WebElements tungsten physics page)
  - benchmark: elastic_modulus
    value: 411
    unit: GPa
    scope: material
    conditions:
      basis: no temperature stated on the page
    method: Young's modulus as printed in the physical properties section
    status: ground
    source: we-physics
    where: Density and elastic properties section, Young's modulus line
  - benchmark: shear_modulus
    value: 161
    unit: GPa
    scope: material
    conditions:
      basis: no temperature stated on the page
    method: Printed as rigidity modulus on the WebElements page
    status: ground
    source: we-physics
    where: Rigidity modulus line
  - benchmark: bulk_modulus
    value: 310
    unit: GPa
    scope: material
    conditions:
      basis: no temperature stated on the page
    method: Printed as bulk modulus on the WebElements page
    status: ground
    source: we-physics
    where: Bulk modulus line
  - benchmark: poissons_ratio
    value: 0.28
    unit: (no units)
    scope: material
    conditions:
      basis: no temperature stated on the page
    method: Printed on the WebElements page
    status: ground
    source: we-physics
    where: Poisson's ratio line
  - benchmark: electrical_resistivity
    value: 5.4e-8
    unit: ohm m
    scope: material
    conditions:
      basis: no temperature stated on the page
    method: Printed as 5.4 x 10-8 ohm m on the WebElements page
    status: ground
    source: we-physics
    where: Electrical resistivity line
  - benchmark: vickers_hardness
    value: 3430
    unit: MN m-2
    scope: material
    conditions:
      basis: no test conditions stated on the page
    method: Printed as Vickers hardness on the WebElements page (not a canonical property name; see gaps)
    status: ground
    source: we-physics
    where: Hardnesses section, Vickers hardness line
  - benchmark: brinell_hardness
    value: 2570
    unit: MN m-2
    scope: material
    conditions:
      basis: no test conditions stated on the page
    method: Printed as Brinell hardness on the WebElements page (not a canonical property name; see gaps)
    status: ground
    source: we-physics
    where: Hardnesses section, Brinell hardness line
  - benchmark: mohs_hardness
    value: 7.5
    unit: (no units)
    scope: material
    conditions:
      basis: mineral hardness scale
    method: Printed as mineral hardness on the WebElements page (not a canonical property name; see gaps)
    status: ground
    source: we-physics
    where: Hardnesses section, Mineral hardness line
  - benchmark: atomic_weight
    value: 183.84
    unit: g/mol
    scope: material
    conditions:
      basis: PubChem record for elemental tungsten (CID 23964) gives the molecular weight, which equals the atomic weight of W
    method: Molecular Weight field of the PubChem compound record
    status: ground
    source: pubchem-w
    where: Molecular Weight (PubChem property table, CID 23964)
corrosion:
  - environment: Air at elevated temperature
    headline: Tungsten oxidises in air and must be protected when hot.
    effect: The WebElements description says the metal oxidises in air and must be protected at elevated temperatures. The HSDB stability entry in PubChem says it oxidises in air at elevated temperature and must be protected.
    rating: moderate
    conditions:
      basis: qualitative statements, no temperatures or exposure times given
    source: we-main
    where: Description paragraph (WebElements main page)
  - environment: Dry air at ordinary temperature
    headline: Stable in dry air at ordinary temperature.
    effect: The HSDB stability entry in PubChem says tungsten is stable in dry air at ordinary temperature. It gives no humidity or exposure data.
    rating: low
    conditions:
      basis: qualitative HSDB statement; no humidity given
    source: pubchem-w
    where: Stability/Shelf Life (HSDB, via PubChem)
  - environment: Mineral acids
    headline: Excellent corrosion resistance; attacked only slightly by most mineral acids.
    effect: The WebElements description says tungsten has excellent corrosion resistance and is attacked only slightly by most mineral acids.
    rating: low
    conditions:
      basis: qualitative statement, no acid concentrations given
    source: we-main
    where: Description paragraph (WebElements main page)
  - environment: Nitric, sulfuric and aqua regia; hydrofluoric plus nitric acid; molten alkali
    headline: Very slow attack in nitric and sulfuric acid; dissolved by hydrofluoric plus nitric acid.
    effect: The CAMEO reactivity profile in PubChem says tungsten is very slowly attacked by nitric acid, sulfuric acid and aqua regia, and dissolved by a mixture of hydrofluoric and nitric acids. It has no reaction with aqueous bases, but it is attacked rapidly by molten alkaline melts such as Na2O2 or KNO3/NaOH.
    rating: severe
    conditions:
      basis: qualitative CAMEO reactivity profile; no temperatures or concentrations given
    source: pubchem-w
    where: Reactivity Profile (CAMEO Chemicals, via PubChem)
risks:
  hazards:
    - text: PubChem's ECHA aggregate of 741 company reports lists Danger, H228 (flammable solid, 73.4% of reports) and H252 (self-heating in large quantities, 47.8%). The same record says 26.5% of reports do not meet GHS criteria.
      ghs:
        - H228
        - H252
      source: pubchem-w
      where: GHS Classification, ECHA aggregated (ref 27)
    - text: PubChem's NITE classification gives H320 (causes eye irritation) and H335 (may cause respiratory irritation), with the Warning signal word.
      ghs:
        - H320
        - H335
      source: pubchem-w
      where: GHS Classification, NITE-CMC (ref 42)
    - text: 'NIOSH pocket guide excerpt in PubChem: exposure by inhalation, ingestion, or skin or eye contact. Symptoms include irritation of the eyes, skin and respiratory system, diffuse pulmonary fibrosis, loss of appetite, nausea, cough and blood changes. Target organs are the eyes, skin, respiratory system and blood.'
      ghs: []
      source: pubchem-w
      where: Health Hazards (NIOSH excerpt in CAMEO Chemicals, via PubChem)
  failure_risks:
    - mode: Dust fire
      trigger: Dust from grinding that accumulates and meets an ignition source
      consequence: CAMEO says tungsten dust may present a moderate fire hazard if allowed to accumulate.
      severity: moderate
      source: pubchem-w
      where: Physical Description (CAMEO Chemicals, via PubChem)
    - mode: Oxidation at elevated temperature
      trigger: Hot tungsten exposed to air without protection
      consequence: The metal oxidises and must be protected at elevated temperatures.
      severity: moderate
      source: we-main
      where: Description paragraph (WebElements main page)
  handling:
    - text: Keep it protected from air when hot. HSDB says it is stable in dry air at ordinary temperature.
      source: pubchem-w
      where: Stability/Shelf Life (HSDB, via PubChem)
    - text: Avoid letting dust from grinding accumulate, and keep ignition sources away from it (CAMEO).
      source: pubchem-w
      where: Physical Description (CAMEO Chemicals, via PubChem)
uses:
  - application: propulsion-and-tanks
    device: Rocket nozzle throat inserts
    example: NASA contract report on tungsten encapsulated, silver-infiltrated porous tungsten rocket nozzle inserts, with design and firing tests of the throat insert. Tungsten was chosen for its high melting point.
    source: ntrs-nozzle
    where: Title page and body text (NASA CR-66759, prepared under NAS 1-4722)
  - application: radiation-shielding
    device: Gamma shield near a space nuclear reactor
    example: A 1973 NASA review recommends a tungsten alloy for gamma shield layers near the reactor, where depleted uranium fissioning would add heat and swelling. It calls tungsten the most efficient gamma attenuator on a minimum-shield-weight basis, though costly.
    source: ntrs-shield-1973
    where: Summary and Introduction; Tungsten heavy-metal alloys section
  - application: mechanisms
    device: Heavy-alloy counterweights and vibration damping
    example: ITIA lists tungsten heavy alloys for ammunition, counterweights, vibration damping and radiation shielding among tungsten metal products.
    source: itia-apps
    where: Tungsten metal products section (ITIA applications page)
  - application: mechanisms
    device: Phone vibration motors (mobile vibrators)
    example: Wikipedia says tungsten is used in vibration motors because its high density, hardness and wear resistance withstand high-speed rotation. Only this secondary source was found for this use.
    source: wiki-tungsten
    where: Applications section (Wikipedia tungsten article)
supply:
  - subject: Tungsten (mine production shares computed from USGS 2025 tonnes of contained W, world total 85,000 t)
    abundance: Crustal abundance not stated in the USGS tungsten summary (see gaps).
    producers:
      - country: China
        share_percent: 78.8
        year: 2025
      - country: Vietnam
        share_percent: 3.5
        year: 2025
      - country: Kazakhstan
        share_percent: 2.8
        year: 2025
      - country: Russia
        share_percent: 2.4
        year: 2025
      - country: Bolivia
        share_percent: 2
        year: 2025
      - country: Australia
        share_percent: 1.2
        year: 2025
    critical_lists: []
    source: usgs-mcs-2026
  - subject: Reserves and trade (USGS 2026 summary)
    abundance: 'China holds 2,500,000 t of W reserves of more than 4,700,000 t world total (about 53%, computed). US mine production is zero; the US is more than 50% net import reliant. Import sources 2021 to 2024: China 26%, Germany 14%, Bolivia 8%, Vietnam 8%. China implemented new export controls on selected tungsten items in February 2025. Rotterdam APT prices rose from $331 to $675 per metric ton unit during 2025.'
    producers: []
    critical_lists: []
    source: usgs-mcs-2026
media: []
documents:
  - title: 'USGS Mineral Commodity Summaries 2026: Tungsten'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tungsten.pdf
    year: 2026
  - title: 'WebElements: Tungsten, physical properties'
    type: database
    url: https://www.webelements.com/tungsten/physics.html
  - title: 'WebElements: Tungsten, key properties'
    type: database
    url: https://www.webelements.com/tungsten/
  - title: 'ITIA: Tungsten properties and intermediates'
    type: datasheet
    url: https://www.itia.info/properties-intermediates/
  - title: 'PubChem: Tungsten (CID 23964), property, GHS and safety records'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Tungsten
  - title: 'NASA: Shield materials recommended for space power nuclear reactors (July 1973)'
    type: report
    url: https://ntrs.nasa.gov/citations/19730018853
    year: 1973
  - title: 'NASA CR-66759: Design, fabrication and evaluation of tungsten encapsulated silver infiltrated porous tungsten rocket nozzle inserts'
    type: report
    url: https://ntrs.nasa.gov/citations/19690016813
gaps:
  - Numeric gamma-ray attenuation (mass attenuation or half-value layer) for tungsten was not read. The NIST XCOM pages returned errors in this run, so the shielding claim rests on a qualitative 1973 NASA review.
  - NIST atomic weight table did not show tungsten in the page we could open; the atomic weight 183.84 comes from PubChem.
  - The Plansee tungsten datasheet returned Access Denied; ITIA and WebElements were used for the physical properties instead.
  - Phone vibration motor use is supported only by Wikipedia, and the brief limits Wikipedia to composition and history. Treat that use as unverified.
  - Vickers hardness, Brinell hardness and Mohs hardness are not canonical property names and were entered as snake_case names.
  - The WebElements physics page gives no test temperature for density, thermal conductivity, CTE or modulus.
  - Crustal abundance of tungsten was not found in the USGS summary, and no supply source for crustal abundance was read.
  - Whether tungsten is on the USGS 2025 critical minerals list or the EU critical raw materials list was not stated in the USGS tungsten summary and was not checked in another source.
  - Secondary (recycled) tungsten quantity for 2025 is withheld in the USGS summary, so recycling share is not given.
  - NASA CR-66759 publication year was not read on the cover; the firing tests it describes are dated 1965 to 1968 in the text.
  - Corrosion data are qualitative; no tungsten corrosion rate in oxidising air or acid was read.
sources:
  we-physics:
    title: 'WebElements: Tungsten, physical properties'
    id: WebElements, tungsten physics page
    url: https://www.webelements.com/tungsten/physics.html
    kind: database
    license: WebElements terms of use (cited, not reproduced)
  we-main:
    title: 'WebElements: Tungsten, key properties and description'
    id: WebElements, tungsten main page
    url: https://www.webelements.com/tungsten/
    kind: database
    license: WebElements terms of use (cited, not reproduced)
  itia:
    title: 'ITIA: Tungsten properties and intermediates'
    id: International Tungsten Industry Association, properties page
    url: https://www.itia.info/properties-intermediates/
    kind: web
    license: ITIA website (cited, not reproduced)
  itia-apps:
    title: 'ITIA: Tungsten applications and markets'
    id: International Tungsten Industry Association, applications page
    url: https://www.itia.info/applications-markets/
    kind: web
    license: ITIA website (cited, not reproduced)
  pubchem-w:
    title: 'PubChem: Tungsten (CID 23964)'
    id: PubChem compound record 23964
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Tungsten
    kind: database
    license: Public domain record (cited, not reproduced)
  usgs-mcs-2026:
    title: 'USGS Mineral Commodity Summaries 2026: Tungsten'
    id: USGS MCS 2026, tungsten
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tungsten.pdf
    year: 2026
    kind: report
    license: US government work (public domain)
  ntrs-shield-1973:
    title: Shield materials recommended for space power nuclear reactors
    id: NASA NTRS 19730018853, July 1973
    url: https://ntrs.nasa.gov/citations/19730018853
    year: 1973
    kind: report
    license: NASA NTRS (public domain, cited)
  ntrs-nozzle:
    title: Design, fabrication and evaluation of tungsten encapsulated silver infiltrated porous tungsten rocket nozzle inserts (NASA CR-66759)
    id: NASA NTRS 19690016813, NASA CR-66759
    url: https://ntrs.nasa.gov/citations/19690016813
    kind: report
    license: NASA NTRS (public domain, cited)
  wiki-tungsten:
    title: 'Wikipedia: Tungsten'
    id: Wikipedia, Tungsten article
    url: https://en.wikipedia.org/wiki/Tungsten
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-19'
review:
  status: draft
  method: assistant
  checked_values: 17
  unreachable: 2
  caveats: 3
  note: 'Read by an AI assistant on 2026-10-19: 17 property values read from WebElements, ITIA and PubChem. Plansee datasheet returned Access Denied and NIST XCOM returned errors; numeric attenuation is missing.'
story:
  recipe:
    line: Elemental tungsten is pure W, a body-centred cubic metal with one tungsten atom per formula unit and an atomic weight of 183.84 (PubChem). Tungsten is also the basis of tungsten carbide, tungsten heavy alloys and the oxides used to make the metal powder (ITIA).
    parts:
      - name: Tungsten
        symbol: W
        atoms: 1
        atomic_weight: 183.84
        role: The whole composition. Pure tungsten is a single element; the body-centred cubic crystal is what gives it its high melting point and stiffness.
  risk_groups:
    - title: For people
      level: 0
      verdict: Hazard classes vary by form
      lead: The metal and its powder carry different notifications in PubChem, and the health data are limited.
      points:
        - label: The powder
          line: PubChem's aggregated notifications list flammable solid (H228) and self-heating (H252) for 73.4% and 47.8% of 741 company reports. The same record says 26.5% of reports do not meet GHS criteria.
        - label: Eyes and breathing
          line: NITE classifies it with H320 (eye irritation) and H335 (respiratory irritation). The NIOSH excerpt lists irritation of the eyes, skin and airways, and in some cases diffuse pulmonary fibrosis.
        - label: Dust
          line: CAMEO says tungsten dust from grinding may present a moderate fire hazard if it accumulates near an ignition source.
    - title: At high temperature
      lead: The main hazard in use is oxidation, not toxicity.
      points:
        - label: In air
          line: WebElements says tungsten oxidises in air and must be protected at elevated temperatures. HSDB says it is stable in dry air at ordinary temperature.
  why: Tungsten (W) is a refractory metal. It melts at about 3,422 degC (ITIA), the highest of any metal. At that temperature most other engineering metals, such as iron, aluminium, copper and titanium, have already vaporised (ITIA). It is also very dense, about 19.3 g/cm3, and stiff, with a Young's modulus of 411 GPa. Those properties explain its uses in rocket nozzle inserts, gamma shields, counterweights and hard alloys. The price is brittleness, difficult forming and a need for protection from air when hot.
  uses:
    - where: Rocket nozzles
      line: A NASA contract report describes tungsten encapsulated, silver-infiltrated porous tungsten nozzle inserts and their firing tests. Tungsten's high melting point is the reason for its use in the throat.
    - where: Gamma shielding near a reactor
      line: A 1973 NASA review recommends a tungsten alloy for the gamma shield near a space reactor. It calls tungsten the most efficient gamma attenuator on a minimum-weight basis, though costly.
    - where: Vibration motors in phones
      line: Wikipedia says tungsten is used in the vibration motors that give phones their tactile alerts, because its density and wear resistance suit high-speed rotation. We did not find a manufacturer or standards source for this use.
    - where: Cutting tools and carbides
      line: The USGS reports that about 60% of US tungsten consumption goes into cemented carbide parts for cutting and wear-resistant applications.
  can_do:
    - label: Melting point
      benchmark: melting_point
      value: 3422 degC
      line: ITIA gives 3,422 +/- 15 degC for the melting point. WebElements gives 3695 K, which is the same temperature in kelvin.
    - label: Density
      benchmark: density
      value: 19.25 g/cm3
      line: Density is 19.25 g/cm3 in ITIA and 19250 kg/m3 in WebElements, so tungsten is among the heaviest metals.
    - label: Stiffness
      benchmark: elastic_modulus
      value: 411 GPa
      line: WebElements gives a Young's modulus of 411 GPa and a shear modulus of 161 GPa.
    - label: Thermal conductivity
      benchmark: thermal_conductivity
      value: 174 W m-1 K-1
      line: WebElements gives 174 W m-1 K-1 at a temperature it does not state.
  compare: Tungsten sits at the top of the metals in melting point, at 3,422 degC, and it is one of the densest, at about 19.3 g/cm3. Its linear thermal expansion coefficient is 4.5 x 10-6 K-1 as printed by WebElements. The table compares its melting point, density and thermal conductivity as printed in the sources.
  compare_rows:
    - scope: material
      label: Melting point
      benchmark: melting_point
    - scope: material
      label: Density
      benchmark: density
    - scope: material
      label: Thermal conductivity
      benchmark: thermal_conductivity
  handling:
    - Protect it from air when hot. WebElements says it oxidises and must be protected at elevated temperatures.
    - Keep grinding dust from building up, since CAMEO notes a moderate fire hazard.
    - Treat it as an eye and airway irritant. NITE classifies it with H320 and H335, and the NIOSH excerpt lists the same organs.
  good_for:
    - Parts used at very high temperature. WebElements says tungsten has the highest tensile strength of all metals in that range.
    - Dense counterweights and gamma shields, where mass per unit of shielding matters more than cost.
  watch_out:
    - Brittle and hard to form. The ITIA says that impurities give it hardness and brittleness, which is why heavy alloys are used for big parts.
    - Oxidises in air when hot, and dust from grinding can be a fire hazard.
    - Supply is concentrated. China produced about 78.8% of 2025 mine output (USGS, computed), and export controls were added in February 2025.
  verdict: Tungsten is the choice when temperature and density matter more than weight or cost. Its melting point and density are well documented; its hardness and gamma attenuation numbers still need an open source before it is used in a design.