{ "spore": "profile", "id": "bismuth", "spore_version": "0.2", "family": "low-melting-metals-and-solders", "name": "Bismuth", "abbreviation": "Bi", "role": "low-melting alloy metal and lead-free substitute", "category": "metals", "type": "heavy-metals", "summary": "Bismuth is the element Bi (atomic number 83), a silver-white metal with a melting point of 271.3 °C according to the PubChem record. Its density is 9.78 g/cm3 at 20 °C, and it expands 3.32 % on solidifying. It is used mainly in low-melting (fusible) alloys, as an additive in brass, free-machining steels and aluminium alloys in place of lead, and in bismuth compounds for pharmaceuticals and pigments. The USGS puts world production at 16,000 t in 2025, with China at 88 % of it. Its weak points are its low thermal conductivity (8 W/(m·K) in WebElements), its low mineral hardness (2.25 in WebElements), and a powder form that PubChem lists as flammable.\n", "best_for": "Lead-free low-melting alloys and solders: melting point 271.3 °C and density 9.78 g/cm3, with no lead content", "weakest_at": "Heat conduction and supply: 8 W/(m·K) thermal conductivity (WebElements), and China produced 88 % of world output in 2025 (USGS)", "identity": { "formula": "Bi (element, atomic number 83)", "cas": "7440-69-9", "designations": [], "source": "durham-sds", "where": "Section 1 (Identification), CAS-No line of the bismuth granules SDS (Alfa Aesar cat. 44807, revision 14 Feb 2020)" }, "tags": { "environments": [], "stresses": [], "applications": [ "electronics-and-chips", "mechanisms", "propulsion-and-tanks" ] }, "properties": [ { "benchmark": "density", "label": "Density of bismuth at 20 °C (PubChem)", "value": 9.78, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "form": "solid metal", "temperature": "20 °C (reference 4 °C)" }, "method": "Value printed in the Experimental Properties section of the PubChem record", "status": "ground", "source": "pubchem-bi", "where": "Experimental Properties, Density, entry 9.78 @ 20 °C/4 °C", "source_detail": { "title": "PubChem compound record: Bismuth (CID 5359367), HSDB, PAC Chemical Database and ECHA GHS entries", "id": "CID 5359367", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5359367/JSON", "year": 2026, "kind": "database", "license": "PubChem (NCBI), public domain; sections attributed to HSDB, PAC and ECHA" } }, { "benchmark": "density", "label": "Density of bismuth at 25 °C (PubChem)", "value": 9.8, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "form": "solid metal", "temperature": "25 °C" }, "method": "Value printed in the Experimental Properties section of the PubChem record", "status": "ground", "source": "pubchem-bi", "where": "Experimental Properties, Density, entry 9.8 @25 °C", "source_detail": { "title": "PubChem compound record: Bismuth (CID 5359367), HSDB, PAC Chemical Database and ECHA GHS entries", "id": "CID 5359367", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5359367/JSON", "year": 2026, "kind": "database", "license": "PubChem (NCBI), public domain; sections attributed to HSDB, PAC and ECHA" } }, { "benchmark": "density", "label": "Density of solid bismuth (WebElements)", "value": 9780, "bound": "exact", "unit": "kg/m3", "scope": "material", "conditions": { "form": "solid", "temperature": "not stated on the page" }, "method": "Value printed on a reference-database physical properties page", "status": "ground", "source": "webelements-bi", "where": "Density properties, Density of solid row (9780 kg m-3)", "source_detail": { "title": "WebElements: Bismuth - 83 Bi, physical properties (Mark Winter, University of Sheffield)", "url": "https://www.webelements.com/bismuth/physics.html", "kind": "database", "license": "WebElements, cited not reproduced" } }, { "benchmark": "melting_point", "label": "Melting point of bismuth", "value": 271.3, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "form": "pure bismuth", "pressure": "not stated" }, "method": "Value printed in the Melting Point section of the PubChem record (PAC Chemical Database entry); the USGS text gives 271 °C", "status": "ground", "source": "pubchem-bi", "where": "Experimental Properties, Melting Point, entry 271.3 °C", "source_detail": { "title": "PubChem compound record: Bismuth (CID 5359367), HSDB, PAC Chemical Database and ECHA GHS entries", "id": "CID 5359367", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5359367/JSON", "year": 2026, "kind": "database", "license": "PubChem (NCBI), public domain; sections attributed to HSDB, PAC and ECHA" } }, { "benchmark": "boiling_point", "label": "Boiling point of bismuth", "value": 1564, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "pressure": "760 mmHg" }, "method": "Value printed in the Boiling Point section of the PubChem record (PAC Chemical Database entry)", "status": "ground", "source": "pubchem-bi", "where": "Experimental Properties, Boiling Point, entry 1564 °C @760 [mm Hg]", "source_detail": { "title": "PubChem compound record: Bismuth (CID 5359367), HSDB, PAC Chemical Database and ECHA GHS entries", "id": "CID 5359367", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5359367/JSON", "year": 2026, "kind": "database", "license": "PubChem (NCBI), public domain; sections attributed to HSDB, PAC and ECHA" } }, { "benchmark": "volume_change_on_solidification", "label": "Volume expansion on solidification", "value": 3.32, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "transition": "liquid to solid at the melting point" }, "method": "Value printed in the Other Experimental Properties section of the PubChem record", "status": "ground", "source": "pubchem-bi", "where": "Experimental Properties, Other Experimental Properties, entry 'EXPANDS 3.32% ON SOLIDIFICATION'", "source_detail": { "title": "PubChem compound record: Bismuth (CID 5359367), HSDB, PAC Chemical Database and ECHA GHS entries", "id": "CID 5359367", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5359367/JSON", "year": 2026, "kind": "database", "license": "PubChem (NCBI), public domain; sections attributed to HSDB, PAC and ECHA" } }, { "benchmark": "electrical_resistivity", "label": "Electrical resistivity of solid bismuth (WebElements)", "value": 130, "bound": "exact", "unit": "µΩ·cm", "scope": "material", "conditions": { "unit_in_source": "130 × 10-8 Ω m", "temperature": "not stated on the page" }, "method": "Value printed on the WebElements page as 130 × 10-8 Ω m; converted by Space Mushroom to µΩ·cm (1 Ω·m = 10^8 µΩ·cm), which gives the same 130 µΩ·cm", "status": "ground", "source": "webelements-bi", "where": "Electrical properties, Electrical resistivity row (130 × 10-8 Ω m; or mΩ cm)", "source_detail": { "title": "WebElements: Bismuth - 83 Bi, physical properties (Mark Winter, University of Sheffield)", "url": "https://www.webelements.com/bismuth/physics.html", "kind": "database", "license": "WebElements, cited not reproduced" } }, { "benchmark": "thermal_conductivity", "label": "Thermal conductivity of bismuth (WebElements)", "value": 8, "bound": "exact", "unit": "W/(m·K)", "scope": "material", "conditions": { "temperature": "not stated on the page" }, "method": "Value printed on a reference-database physical properties page", "status": "ground", "source": "webelements-bi", "where": "Heat and conduction, Thermal conductivity row (8 W m-1 K-1)", "source_detail": { "title": "WebElements: Bismuth - 83 Bi, physical properties (Mark Winter, University of Sheffield)", "url": "https://www.webelements.com/bismuth/physics.html", "kind": "database", "license": "WebElements, cited not reproduced" } }, { "benchmark": "cte", "label": "Coefficient of linear thermal expansion (WebElements)", "value": 13.4, "bound": "exact", "unit": "ppm/K", "scope": "material", "conditions": { "unit_in_source": "10-6 K-1", "temperature": "not stated on the page" }, "method": "Value printed on a reference-database physical properties page", "status": "ground", "source": "webelements-bi", "where": "Heat and conduction, Coefficient of linear thermal expansion row (13.4 × 10-6 K-1)", "source_detail": { "title": "WebElements: Bismuth - 83 Bi, physical properties (Mark Winter, University of Sheffield)", "url": "https://www.webelements.com/bismuth/physics.html", "kind": "database", "license": "WebElements, cited not reproduced" } }, { "benchmark": "elastic_modulus", "label": "Young's modulus of bismuth (WebElements)", "value": 32, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "temperature": "not stated on the page" }, "method": "Value printed on a reference-database physical properties page", "status": "ground", "source": "webelements-bi", "where": "Elastic properties, Young's modulus row (32 GPa)", "source_detail": { "title": "WebElements: Bismuth - 83 Bi, physical properties (Mark Winter, University of Sheffield)", "url": "https://www.webelements.com/bismuth/physics.html", "kind": "database", "license": "WebElements, cited not reproduced" } }, { "benchmark": "shear_modulus", "label": "Rigidity (shear) modulus of bismuth (WebElements)", "value": 12, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "temperature": "not stated on the page" }, "method": "Value printed on a reference-database physical properties page", "status": "ground", "source": "webelements-bi", "where": "Elastic properties, Rigidity modulus row (12 GPa)", "source_detail": { "title": "WebElements: Bismuth - 83 Bi, physical properties (Mark Winter, University of Sheffield)", "url": "https://www.webelements.com/bismuth/physics.html", "kind": "database", "license": "WebElements, cited not reproduced" } }, { "benchmark": "bulk_modulus", "label": "Bulk modulus of bismuth (WebElements)", "value": 31, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "temperature": "not stated on the page" }, "method": "Value printed on a reference-database physical properties page", "status": "ground", "source": "webelements-bi", "where": "Elastic properties, Bulk modulus row (31 GPa)", "source_detail": { "title": "WebElements: Bismuth - 83 Bi, physical properties (Mark Winter, University of Sheffield)", "url": "https://www.webelements.com/bismuth/physics.html", "kind": "database", "license": "WebElements, cited not reproduced" } }, { "benchmark": "poissons_ratio", "label": "Poisson's ratio of bismuth (WebElements)", "value": 0.33, "bound": "exact", "unit": "-", "scope": "material", "conditions": { "temperature": "not stated on the page" }, "method": "Value printed on a reference-database physical properties page", "status": "ground", "source": "webelements-bi", "where": "Elastic properties, Poisson's ratio row (0.33, no units)", "source_detail": { "title": "WebElements: Bismuth - 83 Bi, physical properties (Mark Winter, University of Sheffield)", "url": "https://www.webelements.com/bismuth/physics.html", "kind": "database", "license": "WebElements, cited not reproduced" } }, { "benchmark": "mineral_hardness", "label": "Mineral hardness of bismuth (WebElements)", "value": 2.25, "bound": "exact", "unit": "-", "scope": "material", "conditions": { "temperature": "not stated on the page" }, "method": "Value printed on a reference-database physical properties page; the page gives no scale name beyond 'mineral hardness'", "status": "ground", "source": "webelements-bi", "where": "Hardnesses, Mineral hardness row (2.25, no units)", "source_detail": { "title": "WebElements: Bismuth - 83 Bi, physical properties (Mark Winter, University of Sheffield)", "url": "https://www.webelements.com/bismuth/physics.html", "kind": "database", "license": "WebElements, cited not reproduced" } } ], "corrosion": [ { "environment": "Air at room temperature, then heated in air", "headline": "Bismuth tarnishes in air, and heating in air forms bismuth trioxide.", "effect": "PubChem records that bismuth is superficially oxidized by air, often becoming iridescent, and that when heated in air it forms bismuth trioxide and burns with a blue flame giving yellow oxide fumes. The record gives no oxidation rate, film thickness or humidity dependence.", "rating": "low", "conditions": { "basis": "qualitative statements in the stability and spectra sections of the record; no rate test" }, "source": "pubchem-bi", "where": "Experimental Properties, Stability/Shelf Life; Other Spectra" }, { "environment": "Contact with copper and nickel alloys in a molten bismuth system", "headline": "Molten bismuth appears to attack or alloy with copper and nickel.", "effect": "NASA Marshall built a liquid-bismuth feed system and wrote that bismuth appears to attack or alloy with copper and nickel, so it used unplated stainless-steel gaskets and 316L stainless tubing to resist corrosion. The paper gives no corrosion rate.", "rating": "moderate", "conditions": { "basis": "design choice in a liquid-bismuth test rig at about 300 °C; no measured corrosion rate", "temperature": "near 300 °C (liquid bismuth)" }, "source": "nasa-tm-2007-214958", "where": "Section 3 (VHITAL feed system), VCR fittings and tubing paragraph" } ], "risks": { "hazards": [ { "text": "PubChem reports that 324 of 382 company reports to the ECHA C&L Inventory say bismuth does not meet GHS hazard criteria. Four notifications from 58 reports give hazard codes H370 and H372 with the signal word Danger. The record says the information may vary between notifications depending on impurities and additives.", "ghs": [ "H370", "H372" ], "source": "pubchem-bi", "where": "Hazards Identification, GHS Classification (ECHA C&L notifications summary; hazard statements and signal word)" }, { "text": "Supplier SDS for bismuth granules (Alfa Aesar cat. 44807, revision 14 Feb 2020): the classification criteria under the 2012 OSHA Hazard Communication Standard are not met, and no label elements are given. The acute oral LD50 for bismuth in rats is printed as 5 g/kg.", "ghs": [], "source": "durham-sds", "where": "Section 2 (Hazard identification); Section 11 (Toxicological information, acute toxicity table)" } ], "failure_risks": [ { "mode": "Powder fire", "trigger": "Bismuth in powder form, or in contact with gaseous or liquid chlorine", "consequence": "PubChem records that powdered bismuth burns spontaneously in gaseous chlorine and that bismuth ignites in liquid chlorine at 80 °C. The record lists the powder as flammable.", "severity": "moderate", "source": "pubchem-bi", "where": "Hazards Identification, Fire Potential" }, { "mode": "Violent reaction with oxidizers", "trigger": "Heating bismuth with perchloric acid at 110 °C, or with fused ammonium nitrate", "consequence": "PubChem records that a brown coating forms that explodes violently on further heating, and that the fused-nitrate reaction is often violent and sometimes explosive.", "severity": "moderate", "source": "pubchem-bi", "where": "Stability and Reactivity, Hazardous Reactivities and Incompatibilities" }, { "mode": "Volume expansion on freezing", "trigger": "Bismuth solidifying in a sealed or confined space", "consequence": "The record gives a 3.32 % expansion on solidification. It gives no failure data for confined castings or sealed parts, so the effect on a given part is not assessed here.", "severity": "low", "source": "pubchem-bi", "where": "Other Experimental Properties" } ], "side_effects": [], "handling": [ { "text": "Avoid dust formation and ensure adequate ventilation, as the granule SDS advises for handling.", "source": "durham-sds", "where": "Section 7 (Handling and storage) and Section 6 (Accidental release, containment)" }, { "text": "Keep bismuth away from perchloric acid and fused ammonium nitrate, which the PubChem stability section lists as hazardous mixtures.", "source": "pubchem-bi", "where": "Stability and Reactivity, Hazardous Reactivities and Incompatibilities" } ], "mitigations": [ { "text": "NASA used 316L stainless steel tubing and unplated stainless-steel gaskets for liquid-bismuth lines, and a glass-mica ceramic (Macor) pump body that it calls stable and nonreactive with liquid bismuth near 300 °C.", "source": "nasa-tm-2007-214958", "where": "Section 3 (VHITAL feed system) and Section 4 (EM pump materials)" } ] }, "uses": [ { "application": "electronics-and-chips", "device": "Bismuth-tellurium-oxide alloy film paste for semiconductor devices", "example": "USGS: bismuth-tellurium-oxide alloy film paste is used in the manufacture of semiconductor devices. PubChem also lists thermoelectric materials and semiconductors among bismuth uses.", "source": "usgs-mcs2026-bismuth", "where": "Domestic Production and Use paragraph (last sentence)" }, { "application": "mechanisms", "device": "Fusible alloys: fire-sprinkler triggers and holding devices for lens grinding", "example": "USGS: bismuth fusible alloys are used as a triggering mechanism for fire sprinklers and in holding devices for grinding optical lenses, where a low melting point is ideal.", "source": "usgs-mcs2026-bismuth", "where": "Domestic Production and Use paragraph" }, { "application": "propulsion-and-tanks", "device": "Hall thruster propellant (ground development, not flown)", "example": "NASA Marshall's 2007 technical memorandum describes a liquid bismuth feed system for a bismuth-fed anode-layer thruster. It cites bismuth at 8,000 s specific impulse at more than 70 % efficiency and gives a 2007 propellant cost of 75 dollars per kg against 2,000 dollars per kg for xenon.", "source": "nasa-tm-2007-214958", "where": "Section 1.1 (Motivation), first paragraph" } ], "supply": [ { "subject": "Bismuth (refinery production)", "abundance": "Bismuth reserves and resources were not reported by country (USGS). It is mostly a byproduct of lead ore processing; the USGS names two mines where bismuth was the primary product, the inactive Tasna Mine in Bolivia and one mine in China.", "producers": [ { "country": "China", "share_percent": 88, "year": 2025 }, { "country": "Republic of Korea", "share_percent": 6.3, "year": 2025 }, { "country": "Laos", "share_percent": 3.1, "year": 2025 }, { "country": "Japan", "share_percent": 3.1, "year": 2025 } ], "critical_lists": [], "recycling": "USGS: recycled bismuth-containing alloy scrap was estimated to make up to 10 % of U.S. apparent consumption for 2021 to 2025.", "substitutes": [ "USGS: cadmium, indium, lead and tin can partly replace bismuth in low-temperature solders. Bismuth itself is a nontoxic substitute for lead in plumbing, fishing weights, ammunition, greases and solders." ], "source": "usgs-mcs2026-bismuth", "where": "World Refinery Production and Capacity table, 2025 column (world total 16,000 t; China 88 % as printed in the text; the other shares are calculated by Space Mushroom from 1,000, 500 and 500 t over the 16,000 t world total); Recycling; Substitutes" }, { "subject": "Bismuth imports to the United States", "producers": [ { "country": "China", "share_percent": 56, "year": 2024 }, { "country": "Republic of Korea", "share_percent": 22, "year": 2024 }, { "country": "Germany", "share_percent": 13, "year": 2024 } ], "critical_lists": [], "substitutes": [], "source": "usgs-mcs2026-bismuth", "where": "Import Sources (2021-24) paragraph: China 56 %, Republic of Korea 22 %, Germany 13 %; the year is the end of the 2021 to 2024 period as printed" }, { "subject": "Price and export controls", "producers": [], "critical_lists": [], "substitutes": [], "source": "usgs-mcs2026-bismuth", "where": "Events, Trends, and Issues paragraph; Salient Statistics (price, dollars per pound)" } ], "media": [], "documents": [ { "title": "USGS Mineral Commodity Summaries 2026: Bismuth", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-bismuth.pdf", "year": 2026 }, { "title": "PubChem compound record: Bismuth (CID 5359367), physical properties, GHS classification and uses", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Bismuth", "year": 2026 }, { "title": "WebElements: bismuth physical properties", "type": "database", "url": "https://www.webelements.com/bismuth/physics.html", "year": 2026 }, { "title": "NIST Atomic Weights and Isotopic Compositions for All Elements (bismuth row)", "type": "database", "url": "https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=Bi&all=all&ascii=html", "year": 2026 }, { "title": "NASA/TM-2007-214958: Liquid Bismuth Propellant Management System for the Very High Specific Impulse Thruster With Anode Layer", "type": "report", "url": "https://ntrs.nasa.gov/api/citations/20070035081/downloads/20070035081.pdf", "year": 2007 }, { "title": "Hall-Effect Thruster Utilizing Bismuth as Propellant (NASA NTRS 20080047186, Busek)", "type": "report", "url": "https://ntrs.nasa.gov/citations/20080047186", "year": 2008 }, { "title": "Alfa Aesar bismuth granules safety data sheet, cat. 44807, revision 14 Feb 2020", "type": "sds", "url": "https://www.durhamtech.edu/sites/default/files/safety_data_sheets/Chemistry-and-Biology/Bismuth%20metal%20cas7440-69-9%20SDS.pdf", "year": 2020 }, { "title": "Wikipedia: Bismuth (production as a lead byproduct, history, alloys)", "type": "database", "url": "https://en.wikipedia.org/wiki/Bismuth", "year": 2026 } ], "gaps": [ "Specific heat, electrical conductivity in %IACS, and tensile, yield and elongation values for bismuth were not found in any fetched source, so none are recorded.", "Abundance in the Earth's crust was not read in a fetched source.", "Critical-mineral status of bismuth was not checked against the USGS 2025 list or the EU list in this run, so critical_lists is empty.", "UNS, ASTM, EN and other standard designations were not found in a fetched source; the supplier catalogue number is not a designation and is not recorded.", "Tarnish and oxidation rates at room temperature were not found in a fetched primary source. The 1979 bulk-oxidation paper (Tahboub, El Guindy and Merchant, Oxidation of Metals) was not opened because the publisher page required sign-in, so no values from it are used.", "Radiation-shielding performance of bismuth was seen only in search snippets for open papers that were not opened (JBPE and DOAJ pages returned errors). No shielding value is recorded.", "Supplier SDSs disagree on the flammability of bismuth powder (one search snippet names a flammable-solid classification); only the granule SDS was opened, so the powder classification is not recorded as a value.", "The PubChem GHS notifications do not say which bismuth form each one covers. They are recorded as reported, not as the classification of the metal.", "Outgassing, atomic oxygen, radiation and UV data for bismuth in space were not searched in this run.", "Mineral hardness is recorded under the name mineral_hardness because WebElements does not name the scale, and the volume change on solidification is recorded under volume_change_on_solidification; neither name is in spores/property-canon.yaml.", "The NASA 316L and Macor statements are design choices in one test rig, not corrosion rates." ], "story": { "why": "Bismuth is a silver-white, heavy, low-melting metal. It melts at 271.3 °C and has a density of 9.78 g/cm3 at 20 °C. It is mostly made as a byproduct of lead refining, and it is used in low-melting alloys, as a lead-free additive in brass and steel, and in bismuth compounds. A 2008 Busek report for NASA says bismuth has a larger atomic mass than xenon and is cheaper and more plentiful, which is why it was studied as a Hall-thruster propellant. The USGS puts 2025 world refinery output at 16,000 t, with China at 88 %. Its thermal conductivity of 8 W/(m·K) is low for a metal, and its powder is flammable.", "uses": [ { "where": "Low-melting and fusible alloys", "line": "The USGS lists fusible bismuth alloys for fire-sprinkler triggers, lens-grinding holding devices, and other applications where a low melting point is ideal. Bismuth is also a nontoxic replacement for lead in brass, free-machining aluminium and steel, and solders." }, { "where": "Electronics", "line": "The USGS notes that bismuth-tellurium-oxide alloy film paste is used in the manufacture of semiconductor devices." }, { "where": "Hall-effect thrusters (ground development, not flown)", "line": "NASA Marshall described a liquid-bismuth feed system for an anode-layer thruster. The paper cites 8,000 s specific impulse at more than 70 % efficiency and gives a 2007 propellant cost of 75 dollars per kg against 2,000 dollars per kg for xenon." } ], "can_do": [ { "label": "Melt low", "line": "Bismuth melts at 271.3 °C, the PubChem value; the USGS text gives 271 °C.", "benchmark": "melting_point", "scope": "material", "value": "271.3 °C melting point" }, { "label": "Weight", "line": "Density is 9.78 g/cm3 at 20 °C (PubChem). WebElements gives 9780 kg/m3 for the solid.", "benchmark": "density", "scope": "material", "value": "9.78 g/cm3" }, { "label": "Conduct heat poorly", "line": "WebElements gives a thermal conductivity of 8 W/(m·K). This is a limit for parts that must spread heat.", "benchmark": "thermal_conductivity", "scope": "material", "value": "8 W/(m·K)" }, { "label": "Expand on freezing", "line": "Bismuth expands 3.32 % as it solidifies (PubChem), which affects castings and sealed volumes.", "benchmark": "volume_change_on_solidification", "scope": "material", "value": "3.32 %" } ], "compare": "Bismuth is a dense metal (9.78 g/cm3) that melts at 271.3 °C and conducts heat at 8 W/(m·K). The sources read here give no values for other metals in this collection, so the compare rows show bismuth's own values, and the other profiles should be read against them, not as a ranking.", "compare_rows": [ { "label": "Density", "benchmark": "density", "scope": "material" }, { "label": "Melting point", "benchmark": "melting_point", "scope": "material" }, { "label": "Thermal conductivity", "benchmark": "thermal_conductivity", "scope": "material" } ], "handling": [ "Avoid dust formation and keep the area ventilated, as the supplier SDS advises.", "Keep bismuth away from perchloric acid and fused ammonium nitrate, which PubChem lists as violent mixtures.", "Allow for the 3.32 % expansion on solidification in sealed or confined parts.", "Use 316L stainless steel for liquid-bismuth lines, as NASA did, because bismuth appears to attack copper and nickel." ], "good_for": [ "Lead-free low-melting alloys and solders, where the USGS names bismuth as a nontoxic substitute for lead.", "Fusible holding and trigger devices with a melting point of 271.3 °C (USGS and PubChem)." ], "watch_out": [ "Low heat conduction for a metal: 8 W/(m·K) (WebElements).", "Supply is concentrated: China produced 88 % of world refinery output in 2025 (USGS), and 2025 prices averaged 20 dollars per pound, a record (USGS).", "Flammable as a powder, and violent reactions with some oxidizers (PubChem).", "Hazard classifications conflict: PubChem's notifications give H370 and H372, while the granule SDS does not classify the product.", "No outgassing, atomic oxygen or radiation data for bismuth in space were found in this run." ], "verdict": "Bismuth is a heavy, low-melting metal, with a melting point of 271.3 °C and a density of 9.78 g/cm3. Its main uses are lead-free low-melting alloys and solders, and it is a nontoxic substitute for lead in several products. Its weak points are its low heat conduction, the expansion on freezing, a flammable powder form, conflicting hazard classifications, and a concentrated supply that is mostly in China. The profile lacks specific heat, tensile strength and space-exposure data.", "recipe": { "line": "Bismuth is a single element (Bi, atomic number 83, group 15). Wikipedia says it is produced mainly as a byproduct of lead refining, from crude lead bullion that can contain up to 10 % bismuth. PubChem lists three refining routes for removing bismuth from lead bullion: fractional crystallization, electrolytic (Betts) refining, and the addition of calcium or magnesium (Betterton-Kroll process). The standard atomic weight is 208.98040(1) in the NIST table.", "parts": [ { "name": "Bismuth", "symbol": "Bi", "role": "The whole material. The NIST standard atomic weight is 208.98040(1), printed in the bismuth entry of the NIST table.", "atoms": 1, "atomic_weight": 208.9804 } ] }, "risk_groups": [ { "title": "For people", "lead": "The PubChem hazard codes come from company notifications, and the supplier SDS we read does not classify bismuth granules.", "points": [ { "label": "Bismuth as recorded in PubChem", "line": "Of 382 company reports to the European chemicals agency, 324 say bismuth does not meet GHS criteria. Four notifications from 58 reports give H370 and H372 with the signal word Danger." }, { "label": "Supplier SDS", "line": "The granule SDS we read (revision 14 Feb 2020) says the OSHA classification criteria are not met. It gives an oral LD50 of 5 g/kg in rats and advises avoiding dust." } ], "level": 1, "verdict": "Mixed notifications" }, { "title": "If it fails", "lead": "The failure routes in these sources are a powder fire in chlorine, violent reaction with some oxidizers, and expansion on freezing.", "points": [ { "label": "Powder", "line": "PubChem records that powdered bismuth burns spontaneously in gaseous chlorine and that bismuth ignites in liquid chlorine at 80 °C." }, { "label": "Freezing", "line": "Bismuth expands 3.32 % as it solidifies (PubChem). The record gives no failure data for confined castings." } ] }, { "title": "Handling and storage", "points": [ { "label": "Dust", "line": "Avoid dust formation and keep the area ventilated, as the granule SDS advises." }, { "label": "Incompatible mixtures", "line": "PubChem records a violent reaction when bismuth is heated with perchloric acid and a violent or explosive reaction with fused ammonium nitrate." } ] } ] }, "updated": "2026-10-26", "review": { "status": "draft", "method": "assistant", "checked_values": 14, "unreachable": 3, "caveats": 5, "note": "Values were read by an AI assistant on 2026-10-26 from the pages and PDF named in each entry (USGS text extracted from the PDF; PubChem values from its JSON record; NASA values from the NTRS PDF text). Unreachable: a Springer article (sign-in required), an open shielding paper (JBPE, connection failed) and an Advent pellet page (no bismuth content in the fetched HTML). Caveats: PubChem density and melting values carry no test conditions beyond temperature; the GHS notifications do not say which bismuth form they cover; the WebElements resistivity was converted from Ω m; the USGS 2025 refinery shares other than China are calculated; the NASA corrosion statements are design choices, not rates." }, "sources": { "usgs-mcs2026-bismuth": { "title": "Mineral Commodity Summaries 2026: Bismuth (U.S. Geological Survey)", "id": "USGS MCS 2026, prepared by Kateryna Klochko", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-bismuth.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "pubchem-bi": { "title": "PubChem compound record: Bismuth (CID 5359367), HSDB, PAC Chemical Database and ECHA GHS entries", "id": "CID 5359367", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5359367/JSON", "year": 2026, "kind": "database", "license": "PubChem (NCBI), public domain; sections attributed to HSDB, PAC and ECHA" }, "webelements-bi": { "title": "WebElements: Bismuth - 83 Bi, physical properties (Mark Winter, University of Sheffield)", "url": "https://www.webelements.com/bismuth/physics.html", "kind": "database", "license": "WebElements, cited not reproduced" }, "nist-bi-weights": { "title": "NIST Atomic Weights and Isotopic Compositions for All Elements, bismuth (Bi)", "id": "standard atomic weight 208.98040(1) (bismuth row)", "url": "https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=Bi&all=all&ascii=html", "kind": "database", "license": "US government data" }, "nasa-tm-2007-214958": { "title": "NASA/TM-2007-214958, Liquid Bismuth Propellant Management System for the Very High Specific Impulse Thruster With Anode Layer (K.A. Polzin, T.E. Markusic, B.J. Stanojev)", "id": "NASA/TM-2007-214958, NTRS 20070035081, May 2007", "url": "https://ntrs.nasa.gov/api/citations/20070035081/downloads/20070035081.pdf", "kind": "report", "license": "NASA public technical report" }, "ntrs-busek-2008": { "title": "Hall-Effect Thruster Utilizing Bismuth as Propellant (Szabo, Gasdaska, Hruby, Robin, Busek)", "id": "NTRS 20080047186, report MFS-32440-1, November 2008", "url": "https://ntrs.nasa.gov/citations/20080047186", "kind": "report", "license": "NASA public technical report" }, "durham-sds": { "title": "Safety Data Sheet, Bismuth granules (Alfa Aesar cat. 44807), revision 2, 14 Feb 2020", "id": "CAS 7440-69-9", "url": "https://www.durhamtech.edu/sites/default/files/safety_data_sheets/Chemistry-and-Biology/Bismuth%20metal%20cas7440-69-9%20SDS.pdf", "kind": "datasheet", "license": "supplier document, cited not reproduced" }, "wikipedia-bismuth": { "title": "Bismuth, Wikipedia (production, history and alloys)", "url": "https://en.wikipedia.org/wiki/Bismuth", "kind": "web", "license": "CC BY-SA 4.0, linked not reproduced" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/bismuth/" }