spore: profile id: tantalum spore_version: 0.2 family: refractory-metals name: Tantalum abbreviation: Ta role: dense refractory metal (radiation spot shielding, capacitor anodes) category: shielding type: spot-shields summary: | Tantalum is the element Ta (atomic number 73), a dense, very high-melting refractory metal. Its solid density is 16650 kg/m3 and its melting point is 3017 degC (3290 K), so it is far denser than aluminium and close to tungsten in stopping power per unit thickness. It is used as thin spot shields around sensitive electronics on spacecraft, and as the anode material of tantalum capacitors, which take the largest share of its industrial demand. best_for: Dense, high-melting spot shielding in thin sheet, such as the approximately 1 mm tantalum vault plate on NASA's Europa Clipper weakest_at: 'Mass: the 16650 kg/m3 density makes it heavy for large areas, and the vault plate is only a local shield, not a full enclosure' identity: formula: Ta (element, atomic number 73); body-centred cubic alpha phase at all temperatures up to melting source: webelements-physics where: Atomic structure and solid-state properties sections of the WebElements tantalum page; the page lists atomic number 73 on the main tantalum page tags: environments: [] stresses: - total-radiation-dose applications: - radiation-shielding - electronics-and-chips properties: - benchmark: density label: Density of solid value: 16650 unit: kg/m3 scope: material conditions: form: solid elemental tantalum temperature: not stated on the page method: Value listed in the WebElements physical properties table status: ground source: webelements-physics where: Physical properties table, row Density of solid - benchmark: melting_point label: Melting point value: 3017 unit: degC scope: material conditions: form: elemental tantalum pressure: not stated printed_as: 3290 K method: Value listed in the WebElements tantalum page status: ground source: webelements-main where: Melting point row, printed as 3290 [3017 degC (5463 degF)] K - benchmark: boiling_point label: Boiling point value: 5458 unit: degC scope: material conditions: form: elemental tantalum pressure: not stated printed_as: 5731 K method: Value listed in the WebElements tantalum page status: ground source: webelements-main where: Boiling point row, printed as 5731 [5458 degC (9856 degF)] K - benchmark: youngs_modulus label: Young's modulus value: 186 unit: GPa scope: material conditions: form: elemental tantalum temperature: not stated on the page method: Value listed in the WebElements physical properties table status: ground source: webelements-physics where: Physical properties table, row Young's modulus - benchmark: bulk_modulus label: Bulk modulus value: 200 unit: GPa scope: material conditions: form: elemental tantalum temperature: not stated on the page method: Value listed in the WebElements physical properties table status: ground source: webelements-physics where: Physical properties table, row Bulk modulus - benchmark: poissons_ratio label: Poisson's ratio value: 0.34 unit: dimensionless scope: material conditions: form: elemental tantalum temperature: not stated on the page method: Value listed in the WebElements physical properties table status: ground source: webelements-physics where: Physical properties table, row Poisson's ratio - benchmark: thermal_conductivity label: Thermal conductivity value: 57 unit: W/(m·K) scope: material conditions: form: elemental tantalum temperature: not stated on the page method: Value listed in the WebElements physical properties table status: ground source: webelements-physics where: Physical properties table, row Thermal conductivity - benchmark: thermal_expansion label: Coefficient of linear thermal expansion value: 0.0000063 unit: 1/K scope: material conditions: form: elemental tantalum temperature: not stated on the page method: Value listed in the WebElements physical properties table status: ground source: webelements-physics where: Physical properties table, row Coefficient of linear thermal expansion - benchmark: electrical_resistivity label: Electrical resistivity value: 1.35e-7 unit: ohm·m scope: material conditions: form: elemental tantalum temperature: not stated on the page method: Value listed in the WebElements physical properties table status: ground source: webelements-physics where: Physical properties table, row Electrical resistivity (printed as 13.5 x 10-8 ohm m) - benchmark: vickers_hardness label: Vickers hardness value: 873 unit: MN/m2 scope: material conditions: form: elemental tantalum temperature: not stated on the page method: Value listed in the WebElements physical properties table status: ground source: webelements-physics where: Physical properties table, row Vickers hardness - benchmark: brinell_hardness label: Brinell hardness value: 800 unit: MN/m2 scope: material conditions: form: elemental tantalum temperature: not stated on the page method: Value listed in the WebElements physical properties table status: ground source: webelements-physics where: Physical properties table, row Brinell hardness - benchmark: speed_of_sound label: Velocity of sound value: 3400 unit: m/s scope: material conditions: form: elemental tantalum temperature: not stated on the page method: Value listed in the WebElements physical properties table status: ground source: webelements-physics where: Physical properties table, row Velocity of sound - benchmark: atomic_number label: Atomic number value: 73 unit: dimensionless scope: material conditions: element: tantalum method: Value listed in the WebElements tantalum page status: ground source: webelements-main where: Atomic number row - benchmark: mass_attenuation_coefficient label: Mass attenuation coefficient at 0.1 MeV value: 4.302 unit: cm2/g scope: material conditions: energy: 0.1 MeV photon: 'yes' element: tantalum method: NIST X-ray mass attenuation table, total mass attenuation (mu/rho) status: ground source: nist-xray-z73 where: Row 1.00000E-01 MeV, mu/rho column - benchmark: mass_attenuation_coefficient label: Mass attenuation coefficient at 1 MeV value: 0.06567 unit: cm2/g scope: material conditions: energy: 1 MeV photon: 'yes' element: tantalum method: NIST X-ray mass attenuation table, total mass attenuation (mu/rho) status: ground source: nist-xray-z73 where: Row 1.00000E+00 MeV, mu/rho column - benchmark: mass_attenuation_coefficient label: Mass attenuation coefficient at 10 MeV value: 0.04717 unit: cm2/g scope: material conditions: energy: 10 MeV photon: 'yes' element: tantalum method: NIST X-ray mass attenuation table, total mass attenuation (mu/rho) status: ground source: nist-xray-z73 where: Row 1.00000E+01 MeV, mu/rho column - benchmark: mass_attenuation_coefficient label: Mass attenuation coefficient at 0.1 MeV (aluminium) value: 0.1704 unit: cm2/g scope: material conditions: energy: 0.1 MeV photon: 'yes' element: aluminium method: NIST X-ray mass attenuation table, aluminium comparison status: ground source: nist-xray-z13 where: Row 1.00000E-01 MeV, mu/rho column - benchmark: mass_attenuation_coefficient label: Mass attenuation coefficient at 1 MeV (aluminium) value: 0.06146 unit: cm2/g scope: material conditions: energy: 1 MeV photon: 'yes' element: aluminium method: NIST X-ray mass attenuation table, aluminium comparison status: ground source: nist-xray-z13 where: Row 1.00000E+00 MeV, mu/rho column - benchmark: mass_attenuation_coefficient label: Mass attenuation coefficient at 10 MeV (aluminium) value: 0.02318 unit: cm2/g scope: material conditions: energy: 10 MeV photon: 'yes' element: aluminium method: NIST X-ray mass attenuation table, aluminium comparison status: ground source: nist-xray-z13 where: Row 1.00000E+01 MeV, mu/rho column uses: - application: radiation-shielding device: Spot shield on spacecraft electronics vault example: 'NASA Europa Clipper: a tantalum vault plate about 1 mm thick, 18 by 28 cm, part of the structure that protects the orbiter electronics from Jupiter radiation' source: nasa-europa-clipper where: Placing the Europa Clipper vault plate article, material and purpose paragraphs - application: electronics-and-chips device: Tantalum capacitor anode example: Electronics takes about 55 percent of tantalum demand (2019 estimate by Paumanok), mainly as capacitor anodes source: passive-components-tantalum where: Paragraph on 2019 consumption and electronics share - application: radiation-shielding device: Spot shield (NIST attenuation context) example: Photon mass attenuation values in the properties list compare tantalum with aluminium per gram. source: nist-xray-z73 where: Mass attenuation table, Z = 73 supply: - subject: Tantalum abundance: 'Share of demand from electronics: about 55 percent in 2019 (Paumanok estimate); averaged 50 to 70 percent of total tantalum demand over the past 30 years' recycling: Not sourced in this profile substitutes: [] source: passive-components-tantalum where: Paragraph on 2019 consumption and multi-year electronics share - subject: Tantalum mine production, 2025 estimate (USGS) abundance: World mine total 2,500 t (rounded). Congo (Kinshasa) 1,300 t, Rwanda 400 t, Nigeria 390 t, China 80 t, Australia 50 t. Shares below are each printed value divided by the printed world total. producers: - country: Congo (Kinshasa) share_percent: 52 year: 2025 - country: Rwanda share_percent: 16 year: 2025 - country: Nigeria share_percent: 15.6 year: 2025 - country: China share_percent: 3.2 year: 2025 - country: Australia share_percent: 2 year: 2025 recycling: 'USGS: recycled mostly from new scrap; may account for as much as 30 percent of consumption by domestic primary processors. US recycled amount not available.' substitutes: - niobium and tungsten in carbides - aluminum, ceramics and niobium in electronic capacitors - glass, molybdenum, nickel, niobium, platinum, stainless steel, titanium and zirconium in corrosion-resistant uses - hafnium, iridium, molybdenum, niobium, rhenium and tungsten in high-temperature uses source: usgs-mcs-2026-tantalum where: Salient Statistics table (2025e apparent consumption 890 t, net import reliance 100 percent); World Mine Production table, 2025e column; Recycling and Substitutes paragraphs documents: - title: 'USGS Mineral Commodity Summaries 2026: Tantalum' type: report url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tantalum.pdf year: 2026 - title: 'PubChem: Tantalum (CID 23956), GHS classification' type: database url: https://pubchem.ncbi.nlm.nih.gov/compound/Tantalum year: 2026 media: [] corrosion: - environment: Air at room temperature headline: Forms a very dense Ta2O5 oxide layer that protects the metal. effect: Samaterials says that when exposed to air, tantalum forms a very dense oxide layer (Ta2O5), which protects the base metal. Wikipedia describes the oxide as the basis of tantalum capacitors, where the thin layer acts as the dielectric. rating: unknown conditions: basis: qualitative; no thickness or time given source: samaterials-tantalum-corrosion where: Introduction paragraph on oxide layer; Wikipedia Tantalum, Applications, capacitors paragraph - environment: Most acids and aqua regia below 150 degC headline: Almost immune to attack by aqua regia below 150 degC. effect: Wikipedia says tantalum is almost completely immune to attack by the normally aggressive aqua regia at temperatures below 150 degC, and is inert to most acids. rating: unknown conditions: temperature: below 150 degC basis: Wikipedia summary, no test data source: wikipedia-tantalum where: Properties section, paragraph on corrosion by acids - environment: Hydrofluoric acid headline: 'Unsuitable: attacked by hydrofluoric acid, the main exception.' effect: Samaterials lists hydrofluoric acid below 60 percent as not resistant, with no temperature given, and says tantalum is unsuitable for use in hydrofluoric acid. Wikipedia says it dissolves in hydrofluoric acid and in acidic solutions with fluoride ion. rating: severe conditions: concentration: below 60 percent temperature: not stated source: samaterials-tantalum-corrosion where: Acid resistance table, row Hydrofluoric acid; Wikipedia Properties section - environment: Hot sulfuric acid and hot alkaline solutions headline: Hot sulfuric acid and hot alkaline solutions also corrode it. effect: Wikipedia says tantalum is inert to most acids except hydrofluoric acid and hot sulfuric acid, and that hot alkaline solutions also cause corrosion. Molten potassium hydroxide also dissolves it. rating: moderate conditions: temperature: hot, not stated basis: Wikipedia summary source: wikipedia-tantalum where: Properties section, corrosion paragraphs - environment: Hot acids (hydrogen charging) headline: Hydrogen enters the lattice and makes the metal brittle. effect: Samaterials says that if tantalum is exposed to chemical aggression, hydrogen enters its metal lattice and the material becomes brittle. No hydrogen concentration is given on the page. rating: moderate conditions: basis: qualitative statement, no concentration given source: samaterials-tantalum-corrosion where: Hydrogen embrittlement paragraph risks: hazards: - text: PubChem aggregates GHS reports for tantalum (CID 23956). The main entry, 56 percent of 455 company reports, gives H228 (flammable solid), signal word Danger, class Flam. Sol. 2. 44 percent of reports do not meet GHS criteria. PubChem does not separate bulk metal from powder, so check the SDS for the form you handle. ghs: - 'H228: Flammable solid' source: pubchem-tantalum where: Safety and Hazards, GHS Classification - text: Other ECHA C&L notifications listed by PubChem give H335 (may cause respiratory irritation, signal word Warning) and H302 (harmful if swallowed, signal word Warning). ghs: - 'H335: May cause respiratory irritation' - 'H302: Harmful if swallowed' source: pubchem-tantalum where: Safety and Hazards, GHS Classification, ECHA entries - text: Precautionary statement codes listed by PubChem include P210 (keep away from heat, sparks and open flames), P240 and P241 (grounding, explosion-proof equipment), P280 (protective equipment), P370+P378 (in case of fire, use suitable extinguishing media) and P407. ghs: [] source: pubchem-tantalum where: Safety and Hazards, Precautionary Statement Codes failure_risks: - mode: Hydrogen embrittlement in hot acids trigger: Chemical aggression that lets hydrogen enter the lattice consequence: The metal becomes brittle (samaterials, no concentration given). source: samaterials-tantalum-corrosion where: Hydrogen embrittlement paragraph - mode: Attack by hydrofluoric acid trigger: Contact with hydrofluoric acid below 60 percent consequence: Tantalum is not resistant and is unsuitable for the service (samaterials). source: samaterials-tantalum-corrosion where: Acid resistance table side_effects: [] handling: - text: Keep away from heat, sparks and open flames, and ground equipment when handling powder or swarf (PubChem P210, P240, P241). source: pubchem-tantalum where: Safety and Hazards, Precautionary Statement Codes - text: Wear protective gloves and avoid breathing dust (PubChem P280, H335). source: pubchem-tantalum where: Safety and Hazards, Precautionary Statement Codes - text: Keep away from hydrofluoric acid and hot alkaline solutions (corrosion section). source: pubchem-tantalum where: Corrosion section, hydrofluoric acid row mitigations: [] gaps: - 'Dose reduction or areal density for a tantalum vault against the Jupiter radiation environment: the Juno/Europa vault paper was not found by search in this run, so no mission attenuation figure is recorded.' - 'Corrosion rates in mm/year or mpy: no source with a rate was read in this run.' - 'The hydrogen concentration threshold for embrittlement (a patent gives 100 ppm): the patent page was not fetched, so no value is recorded.' - Mozambique and Brazil mine production rows in the USGS 2026 table are garbled in the PDF text, so they are left out of the shares. - Melting and boiling point and density are printed at the temperature stated in the source only; the density temperature is not stated. - Capacitor-share figures (about 55 percent electronics, 2019) are industry estimates from the Paumanok passive-components article, not a USGS statistic. - 'US production: none, USGS 2025e apparent consumption 890 t, net import reliance 100 percent.' - 'Sensitive-electronics radiation dose tests for a tantalum vault: none sourced.' sources: webelements-physics: title: 'Tantalum - 73Ta: physical properties' url: https://winter.group.shef.ac.uk/webelements/tantalum/physics.html year: 2024 kind: database license: WebElements (University of Sheffield), free online reference webelements-main: title: 'Tantalum - 73Ta: the essentials' url: https://winter.group.shef.ac.uk/webelements/tantalum/ year: 2024 kind: database license: WebElements (University of Sheffield), free online reference nasa-europa-clipper: title: Placing the Europa Clipper vault plate url: https://science.nasa.gov/missions/europa-clipper/placing-the-europa-clipper-vault-plate year: 2024 kind: web license: public domain (NASA) passive-components-tantalum: title: 'Tantalum Supply Routes for Mil-Spec Capacitors: From Ore, to Powder, to Part' url: https://passive-components.eu/tantalum-supply-routes-for-mil-spec-capacitors-from-ore-to-powder-to-part year: 2020 kind: web license: Industry trade article, all rights reserved pubchem-tantalum: title: 'Tantalum (CID 23956): safety and hazards, GHS classification' url: https://pubchem.ncbi.nlm.nih.gov/compound/Tantalum year: 2026 kind: database license: PubChem, public domain wikipedia-tantalum: title: Tantalum url: https://en.wikipedia.org/wiki/Tantalum year: 2026 kind: web license: CC BY-SA 4.0 usgs-mcs-2026-tantalum: title: 'Mineral Commodity Summaries 2026: Tantalum' url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tantalum.pdf year: 2026 kind: report license: US government work, public domain nist-xray-z73: title: 'X-Ray Mass Attenuation Coefficients: Tantalum (Z = 73)' url: https://physics.nist.gov/PhysRefData/XrayMassCoef/ElemTab/z73.html year: 2026 kind: database license: NIST, public domain nist-xray-z13: title: 'X-Ray Mass Attenuation Coefficients: Aluminum (Z = 13)' url: https://physics.nist.gov/PhysRefData/XrayMassCoef/ElemTab/z13.html year: 2026 kind: database license: NIST, public domain samaterials-tantalum-corrosion: title: Corrosion resistance of tantalum to water, aqueous solutions and non-metals url: https://samaterials.com/content/corrosion-resistance-of-tantalum-to-water-aqueous-solutions-and-non-metals.html year: 2026 kind: web license: Vendor web page, all rights reserved license: CC-BY-4.0 status: draft author: assistant story: risk_groups: - title: For people lead: This profile has no sourced health data for tantalum metal. level: 1 verdict: Not assessed in this run points: - label: Metal in use line: Tantalum metal is used as a sealed shield and inside capacitors. No hazard classification was read in this run, so none is stated here. - title: If it fails lead: No sourced failure mode was found in this run. level: 1 verdict: Not assessed points: - label: Mechanical line: The sheet is a local shield. Its density is 16650 kg/m3, and its Vickers hardness is 873 MN/m2. why: Tantalum is dense and melts at 3017 degC, so a thin sheet can block radiation locally without a heavy enclosure. The NASA Europa Clipper vault plate is the sourced example of it on a spacecraft. can_do: - label: Give a dense, value: '' line: Give a dense, high-melting shield in thin sheet on a spacecraft. - label: Serve as the value: '' line: Serve as the anode material of capacitors, which take the largest share of tantalum demand. compare: Tantalum is 16650 kg/m3 and melts at 3017 degC; aluminium, the usual spacecraft shield metal, is far lighter and melts much lower. Its photon mass attenuation is 4.302 cm2/g at 0.1 MeV, against 0.170 cm2/g for aluminium, and 0.06567 cm2/g against 0.06146 cm2/g at 1 MeV (NIST, per gram). Per gram the two are close at 1 MeV, so tantalum wins mainly on density for a thin plate. compare_rows: - scope: material label: Density benchmark: density - scope: material label: Melting point benchmark: melting_point - scope: material label: Thermal conductivity benchmark: thermal_conductivity handling: - Keep away from heat, sparks and open flames, and ground equipment when handling powder or swarf (PubChem P210, P240, P241). - Wear protective gloves and avoid breathing dust (PubChem P280, H335). - Keep away from hydrofluoric acid and hot alkaline solutions (corrosion section). good_for: - Local radiation spot shields around sensitive electronics. watch_out: - Its mass is high for large areas. - Hydrofluoric acid and hydrogen uptake in hot acids limit its use in chemical service. - The NIST values are per gram of material; no dose reduction in a spacecraft vault was sourced in this run. verdict: Tantalum is a dense, high-melting metal used as local spot shielding and as capacitor anode material. This deepened draft adds recipe, supply shares from the USGS 2026 summary, corrosion, hazards from PubChem, and NIST photon attenuation against aluminium. recipe: line: Tantalum is the element Ta, atomic number 73, a single-element metal with no alloying in pure form. Its ore is mainly tantalite, (Fe,Mn)Ta2O6, usually mined with columbite, the niobium ore. Ore is concentrated by gravity separation, leached with hydrofluoric acid and sulfuric or hydrochloric acid, and purified by solvent extraction into an organic solvent. Niobium is removed by lowering the acid ionic strength, and the tantalum is then precipitated with ammonia and calcined to Ta2O5. The metal is made by reducing the purified salt or oxide; The first metal was made by reducing tantalum chloride in hydrogen, as de Marignac did in the 19th century. The metal powder is pressed into pellets for capacitors. parts: - name: Tantalum symbol: Ta atoms: 1 atomic_weight: 180.94788 role: The whole material. WebElements prints the relative atomic mass as 180.94788 (2). Natural tantalum is almost entirely one isotope, with a very small share of a metastable isomer (Wikipedia). checked_values: 19