{ "spore": "profile", "id": "erbium", "spore_version": "0.2", "family": "rare-earth-metals", "name": "Erbium", "abbreviation": "Er", "role": "optical fibre amplifier dopant and near-infrared laser ion", "category": "metals", "type": "heavy-metals", "summary": "Erbium is the element Er (atomic number 68), a soft, silvery lanthanide metal with a density of 9.065 g/cm3 at 20 °C and a melting point of 1529 °C (Wikipedia). Its principal commercial sources are the minerals xenotime and euxenite, and it is also found in monazite and bastnasite (Wikipedia). Its best known use is as the active element in erbium-doped optical silica fibre, used in fibre amplifiers for long-distance optical links (Wikipedia). A compact erbium-doped amplifier with an output above 2 W has been designed for a 6U CubeSat in low Earth orbit (NICT). In fine form the metal is classed as a flammable solid (PubChem H228), and it reacts with hot water and dilute acids. The USGS reports that China supplied 71 % of U.S. imports of rare-earth compounds and metals in 2021 to 2024, and that China added erbium to its export controls in October.\n", "best_for": "Optical fibre amplifiers, where erbium is the active dopant in silica fibre (Wikipedia)", "weakest_at": "Fine metal is flammable (PubChem H228), and the metal reacts with hot water and dilute acids and tarnishes in moist air (Wikipedia, Stanford Advanced Materials)", "identity": { "formula": "Er (element, atomic number 68); hexagonal close-packed crystal structure at room temperature (Wikipedia)", "cas": "7440-52-0", "designations": [], "source": "pubchem-er", "where": "Other Identifiers, CAS entry (PubChem CID 23980)" }, "tags": { "environments": [ "low-earth-orbit" ], "stresses": [], "applications": [ "optics-and-cameras" ] }, "properties": [ { "benchmark": "density", "label": "Density, erbium at 20 °C", "value": 9.065, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "temperature": "20 °C", "unit_in_source": "9.065 g/cm3" }, "method": "Value printed in the Wikipedia infobox, Density (at 20° C) row", "status": "ground", "source": "wikipedia-er", "where": "Infobox, row Density (at 20° C)", "source_detail": { "title": "Erbium (Wikipedia)", "url": "https://en.wikipedia.org/wiki/Erbium", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0 (cited, not reproduced)" } }, { "benchmark": "density", "label": "Density, erbium foil at 20 °C", "value": 9.051, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "temperature": "20 °C", "form": "foil, 99 % (2N) light tight" }, "method": "Value printed in a supplier product datasheet", "status": "ground", "note": "The Wikipedia infobox gives 9.065 g/cm3 for the bulk metal, so the two values differ by 0.014 g/cm3.", "source": "goodfellow-er-foil", "where": "Physical properties table, row Density (9.051@20°C)", "source_detail": { "title": "Erbium foil light tight group (Goodfellow product datasheet, UK)", "url": "https://www.goodfellow.com/uk/erbium-foil-light-tight-group", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "density", "label": "Specific gravity, erbium metal", "value": 9.01, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "unit_in_source": "9.01 G/CC", "basis": "specific gravity, water = 1" }, "method": "Value printed in a safety data sheet, Section III Physical/Chemical Characteristics", "status": "ground", "source": "sam-er-msds", "where": "Section III, row Specific gravity (water=1)", "source_detail": { "title": "Material Safety Data Sheet: Erbium Metal (Stanford Advanced Materials, 2012), copy hosted by Sputtertargets.net", "url": "https://www.sputtertargets.net/Public/pdf/erbium-msds.pdf", "year": 2012, "kind": "datasheet", "license": "supplier safety data sheet, cited not reproduced" } }, { "benchmark": "melting_point", "label": "Melting point, erbium", "value": 1529, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "unit_in_source": "1802 K (1529 °C, 2784 °F)", "pressure": "not stated" }, "method": "Value printed in the Wikipedia infobox, Melting point row", "status": "ground", "source": "wikipedia-er", "where": "Infobox, row Melting point", "source_detail": { "title": "Erbium (Wikipedia)", "url": "https://en.wikipedia.org/wiki/Erbium", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0 (cited, not reproduced)" } }, { "benchmark": "melting_point", "label": "Melting point, erbium metal (safety data sheet)", "value": 1529, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "unit_in_source": "1529.0°C" }, "method": "Value printed in a safety data sheet, Section III Freezing/Melting Point", "status": "ground", "source": "sam-er-msds", "where": "Section III, Freezing/Melting Point", "source_detail": { "title": "Material Safety Data Sheet: Erbium Metal (Stanford Advanced Materials, 2012), copy hosted by Sputtertargets.net", "url": "https://www.sputtertargets.net/Public/pdf/erbium-msds.pdf", "year": 2012, "kind": "datasheet", "license": "supplier safety data sheet, cited not reproduced" } }, { "benchmark": "melting_point", "label": "Melting point, erbium foil", "value": 1529, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "form": "foil, 99 % (2N) light tight" }, "method": "Value printed in a supplier product datasheet", "status": "ground", "source": "goodfellow-er-foil", "where": "Thermal properties table, row Melting point (C) 1529", "source_detail": { "title": "Erbium foil light tight group (Goodfellow product datasheet, UK)", "url": "https://www.goodfellow.com/uk/erbium-foil-light-tight-group", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "boiling_point", "label": "Boiling point, erbium", "value": 2868, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "unit_in_source": "3141 K (2868 °C, 5194 °F)", "pressure": "not stated in the infobox" }, "method": "Value printed in the Wikipedia infobox, Boiling point row", "status": "ground", "note": "The safety data sheet and the foil datasheet give 2863 °C, so the sources differ by 5 °C. Both are recorded.", "source": "wikipedia-er", "where": "Infobox, row Boiling point", "source_detail": { "title": "Erbium (Wikipedia)", "url": "https://en.wikipedia.org/wiki/Erbium", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0 (cited, not reproduced)" } }, { "benchmark": "boiling_point", "label": "Boiling point, erbium metal (safety data sheet)", "value": 2863, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "unit_in_source": "2863.0°C" }, "method": "Value printed in a safety data sheet, Section III Boiling Point", "status": "ground", "source": "sam-er-msds", "where": "Section III, Boiling Point", "source_detail": { "title": "Material Safety Data Sheet: Erbium Metal (Stanford Advanced Materials, 2012), copy hosted by Sputtertargets.net", "url": "https://www.sputtertargets.net/Public/pdf/erbium-msds.pdf", "year": 2012, "kind": "datasheet", "license": "supplier safety data sheet, cited not reproduced" } }, { "benchmark": "boiling_point", "label": "Boiling point, erbium foil", "value": 2863, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "form": "foil, 99 % (2N) light tight" }, "method": "Value printed in a supplier product datasheet", "status": "ground", "source": "goodfellow-er-foil", "where": "Physical properties table, row Boiling point (C) 2863", "source_detail": { "title": "Erbium foil light tight group (Goodfellow product datasheet, UK)", "url": "https://www.goodfellow.com/uk/erbium-foil-light-tight-group", "kind": "datasheet", "license": "supplier web page, cited not reproduced" } }, { "benchmark": "thermal_conductivity", "label": "Thermal conductivity, erbium", "value": 14.5, "bound": "exact", "unit": "W/(m⋅K)", "scope": "material", "conditions": { "temperature": "not stated", "unit_in_source": "14.5 W/(m⋅K)" }, "method": "Value printed in the Wikipedia infobox; no temperature is given", "status": "ground", "source": "wikipedia-er", "where": "Infobox, row Thermal conductivity", "source_detail": { "title": "Erbium (Wikipedia)", "url": "https://en.wikipedia.org/wiki/Erbium", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0 (cited, not reproduced)" } }, { "benchmark": "electrical_resistivity", "label": "Electrical resistivity, polycrystalline erbium at room temperature", "value": 0.86, "bound": "exact", "unit": "µΩ⋅m", "scope": "material", "conditions": { "temperature": "r.t. (room temperature, as printed)", "form": "polycrystalline (poly)", "unit_in_source": "0.860 µΩ⋅m" }, "method": "Value printed in the Wikipedia infobox, Electrical resistivity row", "status": "ground", "source": "wikipedia-er", "where": "Infobox, row Electrical resistivity, poly", "source_detail": { "title": "Erbium (Wikipedia)", "url": "https://en.wikipedia.org/wiki/Erbium", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0 (cited, not reproduced)" } }, { "benchmark": "elastic_modulus", "label": "Young's modulus, erbium", "value": 69.9, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "temperature": "not stated" }, "method": "Value printed in the Wikipedia infobox", "status": "ground", "source": "wikipedia-er", "where": "Infobox, row Young's modulus", "source_detail": { "title": "Erbium (Wikipedia)", "url": "https://en.wikipedia.org/wiki/Erbium", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0 (cited, not reproduced)" } }, { "benchmark": "vickers_hardness", "label": "Vickers hardness, erbium", "value": 430, "value_high": 700, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "temperature": "not stated", "unit_in_source": "430–700 MPa" }, "method": "Range printed in the Wikipedia infobox, Vickers hardness row", "status": "ground", "note": "No canonical name exists for hardness in the property file, so vickers_hardness is a new name and is listed in gaps.", "source": "wikipedia-er", "where": "Infobox, row Vickers hardness", "source_detail": { "title": "Erbium (Wikipedia)", "url": "https://en.wikipedia.org/wiki/Erbium", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0 (cited, not reproduced)" } }, { "benchmark": "brinell_hardness", "label": "Brinell hardness, erbium", "value": 600, "value_high": 1070, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "temperature": "not stated", "unit_in_source": "600–1070 MPa" }, "method": "Range printed in the Wikipedia infobox, Brinell hardness row", "status": "ground", "note": "No canonical name exists for Brinell hardness in the property file, so brinell_hardness is a new name and is listed in gaps.", "source": "wikipedia-er", "where": "Infobox, row Brinell hardness", "source_detail": { "title": "Erbium (Wikipedia)", "url": "https://en.wikipedia.org/wiki/Erbium", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0 (cited, not reproduced)" } } ], "corrosion": [ { "environment": "Moist air", "headline": "Erbium keeps its lustre in dry air but tarnishes slowly in moist air.", "effect": "Wikipedia says erbium retains its luster in dry air but will slowly tarnish in moist air, and that it burns readily to form erbium(III) oxide. No temperature is given.", "rating": "moderate", "conditions": { "atmosphere": "dry air and moist air", "temperature": "not stated" }, "source": "wikipedia-er", "where": "Chemical properties, Air paragraph" }, { "environment": "Cold and hot water", "headline": "Erbium reacts slowly with cold water and quite quickly with hot water.", "effect": "Wikipedia gives the reaction rates without temperatures. The safety data sheet lists water and moisture among the materials erbium is incompatible with.", "rating": "severe", "conditions": { "temperature": "not stated" }, "source": "wikipedia-er", "where": "Chemical properties, Water paragraph" }, { "environment": "Dilute acids", "headline": "Erbium dissolves readily in dilute sulfuric acid and releases flammable hydrogen gas.", "effect": "Wikipedia says erbium dissolves readily in dilute sulfuric acid. The safety data sheet says the metal reacts with dilute acids and emits flammable and explosive hydrogen gas.", "rating": "severe", "conditions": { "acid": "dilute sulfuric acid, and dilute acids in general", "temperature": "not stated" }, "source": "sam-er-msds", "where": "Section IV Fire and Explosion Hazard Data; Section VI Reactivity Data" }, { "environment": "Air, moisture, acids, oxidizing materials and halogens", "headline": "The safety data sheet lists air, moisture, acids, oxidizers and halogens as incompatible materials.", "effect": "The sheet lists these as incompatibilities and gives hydrogen as the decomposition product. No rate or threshold is given.", "rating": "moderate", "conditions": { "form": "metal" }, "source": "sam-er-msds", "where": "Section VI Reactivity Data, Incompatibility" } ], "risks": { "hazards": [ { "text": "PubChem GHS summary, ECHA C&L notifications: H228 (93.3 %): Flammable solid, signal word Danger, class Flam. Sol. 1. Of 104 company reports, 5 (4.8 %) say the substance does not meet GHS criteria, so classification depends on the notifier and the form.", "ghs": [ "H228" ], "source": "pubchem-er", "where": "Safety and Hazards, Hazards Identification, GHS Classification" }, { "text": "Goodfellow erbium foil product page shows a GHS02 Flammable pictogram and a shipping restriction note.", "ghs": [], "source": "goodfellow-er-foil", "where": "Hazards section of the product page" }, { "text": "Safety data sheet, erbium metal (Stanford Advanced Materials, revised 2012): the sheet gives no GHS hazard statements. It says the chemical, physical and toxicological properties have not been thoroughly investigated. Fumes from a fire are hazardous.", "ghs": [], "source": "sam-er-msds", "where": "Section V Health Hazard Data, opening paragraph; Section IV Special Fire Fighting Procedures" } ], "failure_risks": [ { "mode": "Fire in fine metal", "trigger": "Finely divided erbium exposed to a flame or spark", "consequence": "PubChem quotes Hawley that fine metal is flammable. The Goodfellow sheet carries the flammable pictogram.", "severity": "moderate", "source": "pubchem-er", "where": "Safety and Hazards, Hazards Summary" }, { "mode": "Hydrogen release on contact with acid", "trigger": "Erbium metal in contact with dilute acids", "consequence": "The metal emits flammable and explosive hydrogen gas (Stanford Advanced Materials).", "severity": "critical", "source": "sam-er-msds", "where": "Section IV Special Fire Fighting Procedures" }, { "mode": "Reaction with hot water", "trigger": "Erbium metal in contact with hot water", "consequence": "Wikipedia says the metal reacts quite quickly with hot water, and that it reacts slowly with cold water.", "severity": "moderate", "source": "wikipedia-er", "where": "Chemical properties, Water paragraph" }, { "mode": "Tarnish in moist air", "trigger": "Long exposure to moist air", "consequence": "The surface tarnishes slowly, and the sheet gives no rate.", "severity": "low", "source": "wikipedia-er", "where": "Chemical properties, Air paragraph" } ], "side_effects": [ { "text": "Dust may cause asthma attacks and lung damage, including lung granulomas, and the skin and lungs can develop granulomas after exposure to rare earth metals (Stanford Advanced Materials).", "affects": "People handling dust and fine swarf", "source": "sam-er-msds", "where": "Section V Health Hazard Data, Inhalation and Skin paragraphs" } ], "handling": [ { "text": "Store in a cool, dry area in a tightly sealed container (Stanford Advanced Materials).", "source": "sam-er-msds", "where": "Section VII Hazard Label Information" }, { "text": "Handle in a dry, controlled atmosphere. Wear a NIOSH approved respirator, impervious rubber gloves and safety glasses (Stanford Advanced Materials).", "source": "sam-er-msds", "where": "Section VIII Control Measures, Protective Equipment Summary and Special" }, { "text": "Use Class D or another suitable metal extinguishing agent on fires, and do not use water (Stanford Advanced Materials).", "source": "sam-er-msds", "where": "Section IV Fire Extinguishing Media" }, { "text": "Vacuum up spills with a HEPA filter and place the waste in a closed container, taking care not to raise dust (Stanford Advanced Materials).", "source": "sam-er-msds", "where": "Section VII Steps to be taken in case material is released or spilled" } ], "mitigations": [] }, "uses": [ { "application": "optics-and-cameras", "device": "Erbium-doped optical fibre amplifiers in telecom and long-distance optical links", "example": "Wikipedia says erbium-doped optical silica-glass fibres are the active element in erbium-doped fibre amplifiers.", "source": "wikipedia-er", "where": "Applications, Lasers and optics" }, { "application": "optics-and-cameras", "device": "Compact erbium-doped fibre amplifier for a 6U CubeSat optical terminal in low Earth orbit", "example": "NICT reports a two-stage erbium-doped fibre amplifier for the CubeSOTA 6U CubeSat, with a high-power amplifier that delivers an output above 2 W. The paper gives a total ionising dose test above 20 krad and vibration and thermal vacuum tests.", "source": "nict-edfa-frontiers", "where": "Abstract; Section 2 Table 1; Section 3 Environmental validation" }, { "application": "optics-and-cameras", "device": "Space-qualified erbium/ytterbium fibre amplifier for satellite links", "example": "Agiltron describes a vacuum-rated erbium/ytterbium amplifier for satellite communication, typically designed to function reliably for over 10 years. The page does not name a satellite or mission.", "source": "agiltron-space-edfa", "where": "Description and Features section" }, { "application": "optics-and-cameras", "device": "Medical erbium lasers", "example": "Wikipedia says medical laser uses of erbium utilise the erbium ion's 2940 nm emission, as in Er:YAG lasers.", "source": "wikipedia-er", "where": "Applications, Lasers and optics" } ], "supply": [ { "subject": "Erbium abundance in the Earth's crust", "abundance": "About 2.8 mg/kg in the Earth's crust (Wikipedia)", "producers": [], "critical_lists": [], "substitutes": [], "source": "wikipedia-er", "where": "Occurrence section" }, { "subject": "Erbium ores", "abundance": "The principal commercial sources are the minerals xenotime and euxenite, and erbium is also found in monazite and bastnasite (Wikipedia). Erbia is about 4 to 5 % in high-yttrium concentrates (Wikipedia).", "producers": [], "critical_lists": [], "substitutes": [], "source": "wikipedia-er", "where": "Occurrence and Production sections; Isotopes and natural occurrence" }, { "subject": "Rare-earth compounds and metals, U.S. import sources 2021 to 2024 (group total, erbium not separated)", "producers": [ { "country": "China", "share_percent": 71 }, { "country": "Malaysia", "share_percent": 13 }, { "country": "Japan", "share_percent": 5 }, { "country": "Estonia", "share_percent": 5 }, { "country": "other", "share_percent": 6 } ], "critical_lists": [], "substitutes": [], "source": "usgs-rare-earths", "where": "Import Sources (2021 to 2024) paragraph. These are U.S. import shares, not world production shares." }, { "subject": "World rare-earth mine production and reserves (group total, erbium not separated)", "abundance": "Mine production, China 270,000 (2024) and 270,000 (2025); United States 45,500 (2024) and 51,000 (2025); world total 380,000 (2024) and 390,000 (2025). China reserves 44,000,000. Units as printed in the USGS table.", "producers": [], "critical_lists": [], "substitutes": [], "source": "usgs-rare-earths", "where": "Mine production and reserves table, World total row." }, { "subject": "Recycling and substitutes (rare earths)", "producers": [], "critical_lists": [], "recycling": "USGS: limited quantities of rare earths were recovered from batteries, permanent magnets and fluorescent lamps.", "substitutes": [ "USGS: substitutes are available for many applications but generally are less effective." ], "source": "usgs-rare-earths", "where": "Recycling paragraph; Substitutes paragraph" }, { "subject": "Export controls on erbium", "abundance": "China tightened its rare-earth export controls in April 2025, and in October it expanded them to include erbium. In November it suspended the October controls for one year.", "producers": [], "critical_lists": [], "substitutes": [], "source": "usgs-rare-earths", "where": "Events, Trends, and Issues" } ], "media": [], "documents": [ { "title": "USGS Mineral Commodity Summaries 2026: Rare Earths", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf", "year": 2026 }, { "title": "Wikipedia: Erbium", "type": "database", "url": "https://en.wikipedia.org/wiki/Erbium", "year": 2026 }, { "title": "PubChem compound record for erbium (CID 23980), including ECHA C&L Inventory classification", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/23980" }, { "title": "Material Safety Data Sheet: Erbium Metal (Stanford Advanced Materials, revision 2.0, 2012), copy hosted by Sputtertargets.net", "type": "sds", "url": "https://www.sputtertargets.net/Public/pdf/erbium-msds.pdf", "year": 2012 }, { "title": "Erbium foil light tight group (Goodfellow product datasheet, UK)", "type": "datasheet", "url": "https://www.goodfellow.com/uk/erbium-foil-light-tight-group" }, { "title": "Frontiers in Physics 2025: compact erbium-doped fibre amplifier for the CubeSOTA CubeSat optical terminal (NICT)", "type": "paper", "url": "https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2025.1542043/full", "year": 2025 }, { "title": "Agiltron space-qualified erbium/ytterbium small signal fibre amplifier (product page)", "type": "datasheet", "url": "https://agiltron.com/?p=22667" } ], "gaps": [ "Erbium is not separated in the USGS rare-earths report. The supply shares and production figures are for the rare-earth group, so no erbium-specific production share is given.", "Critical-mineral listing: the USGS rare-earths text read here does not state a critical-minerals listing for erbium, so critical_lists is empty.", "World erbium production and reserves: not found in the sources read.", "PubChem record CID 23980: the JSON read gives no experimental melting point, boiling point or density, and no OSHA or NIOSH exposure limit for erbium. The safety data sheet gives PEL and TLV as NE (not established), so no exposure limit is entered.", "Designations: no UNS, EN, ASTM or trade code for erbium metal was printed by a source read in this run, so designations are left out.", "Vickers and Brinell hardness are entered under new names (vickers_hardness and brinell_hardness) because the property file has no canonical name for hardness. Both are printed in MPa as ranges.", "Boiling point and density differ between sources: Wikipedia gives 2868 °C and 9.065 g/cm3, while the safety data sheet and the foil datasheet give 2863 °C and 9.051 to 9.01 g/cm3. All values are recorded with their sources.", "Melting point 1497 °C appears in American Elements and a university periodic table, but neither page could be read in full (American Elements returned HTTP 403) and the periodic table gives no unit, so it is not entered.", "Specific heat, thermal expansion, shear modulus, Poisson's ratio, emissivity and thermal neutron cross-section for erbium were not found in the sources read.", "Mechanical properties of erbium metal (yield, tensile, elongation) were not found in the sources read.", "Quantitative corrosion data (rates, mass gain, threshold temperatures) were not found. Corrosion entries are qualitative and come from Wikipedia and the safety data sheet.", "Hazard classification differs by source: PubChem gives H228 (flammable solid) for 93.3 % of notifications, the Goodfellow foil page shows a flammable pictogram, and the Stanford Advanced Materials sheet gives no H statements. The Fisher Scientific and Glentham pages timed out or were not readable, and the UMN safety data sheet could not be downloaded.", "Space environment for the metal itself: none found. The NICT and Agiltron results are for amplifier hardware, not for erbium metal, and the radiation and thermal results are not entered as material properties.", "Production route: Wikipedia has a Production section that was not read in detail, so no process steps are described in the recipe.", "Media: no image with a usable licence was sourced in this run.", "Seven sources were read in this run, one short of the eight asked for. The two blocked suppliers and the UMN safety data sheet were the sources lost." ], "story": { "why": "Erbium is a rare earth metal whose main value is in optics. Its atoms emit and amplify light in silica fibre, which makes erbium-doped fibre amplifiers central to long-distance optical links (Wikipedia). It is also the source of a 2940 nm laser emission used in medical lasers (Wikipedia). Its supply is concentrated, since the USGS reports China as the source of 71 % of U.S. imports of rare-earth compounds and metals in 2021 to 2024, and China added erbium to its export controls in October.", "uses": [ { "where": "Optical fibre amplifiers", "line": "Erbium-doped silica fibre is the active element of fibre amplifiers used in optical links (Wikipedia)." }, { "where": "CubeSat optical terminal", "line": "NICT reports a compact two-stage erbium-doped amplifier for the 6U CubeSOTA CubeSat in low Earth orbit, with an output above 2 W (Frontiers in Physics 2025)." }, { "where": "Satellite links", "line": "Agiltron sells a vacuum-rated erbium/ytterbium amplifier for satellite communication, designed for over 10 years of reliable operation (product page)." }, { "where": "Medical lasers", "line": "Wikipedia says medical uses of erbium utilise the erbium ion's 2940 nm emission, as in Er:YAG lasers." } ], "can_do": [ { "label": "Amplify light", "line": "Erbium-doped silica fibre is the active element of fibre amplifiers (Wikipedia).", "scope": "material", "value": "Erbium-doped fibre" }, { "label": "Weight", "line": "Density is 9.065 g/cm3 at 20 °C in the Wikipedia infobox, and 9.051 g/cm3 at 20 °C for the Goodfellow foil.", "benchmark": "density", "scope": "material", "value": "9.065 g/cm3" }, { "label": "Melting", "line": "Melting point is 1529 °C in the Wikipedia infobox, the safety data sheet and the Goodfellow foil datasheet.", "benchmark": "melting_point", "scope": "material", "value": "1529 °C" }, { "label": "Carry heat", "line": "Thermal conductivity is 14.5 W/(m⋅K), with no temperature given (Wikipedia).", "benchmark": "thermal_conductivity", "scope": "material", "value": "14.5 W/(m⋅K)" }, { "label": "Stiffness", "line": "Young's modulus is 69.9 GPa (Wikipedia infobox).", "benchmark": "elastic_modulus", "scope": "material", "value": "69.9 GPa" } ], "compare": "Erbium is a rare earth metal of moderate density, 9.065 g/cm3 at 20 °C, and it melts at 1529 °C (Wikipedia). Its Young's modulus is 69.9 GPa (Wikipedia). It is used for its optical behaviour in fibre amplifiers, not for structural strength, so the strength and melting rows should be read as basic metal data rather than as a design comparison.", "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": [ "Store in a cool, dry area in a tightly sealed container (Stanford Advanced Materials).", "Handle in a dry, controlled atmosphere and wear a NIOSH approved respirator, rubber gloves and safety glasses (Stanford Advanced Materials).", "Use Class D or another metal extinguishing agent on fires, and do not use water (Stanford Advanced Materials)." ], "good_for": [ "Optical amplification: erbium-doped silica fibre amplifies light in optical links (Wikipedia).", "Compact space hardware: a 2 W erbium-doped CubeSat amplifier is designed for low Earth orbit (NICT).", "Medical lasers: the 2940 nm erbium emission is used in Er:YAG lasers (Wikipedia)." ], "watch_out": [ "Fine metal is a flammable solid (PubChem H228), and the metal releases hydrogen on contact with acid.", "Sources disagree on the classification, and the metal's toxicology is incompletely studied (Stanford Advanced Materials).", "Supply is concentrated in China, which added erbium to its export controls in October (USGS).", "The supply shares are for the whole rare-earth group, so no erbium-specific production figure is available." ], "verdict": "Erbium is a rare earth metal whose value lies in optical amplification, and its density of 9.065 g/cm3 and melting point of 1529 °C are well documented. Its flammability in fine form and its reaction with acid and hot water need the handling steps above. Its supply data are for the rare-earth group rather than erbium alone, and the hardness and toxicology data are thinner than the physical values.", "recipe": { "line": "Erbium is a single-element metal (Er) with a hexagonal close-packed structure at room temperature (Wikipedia). Commercial pieces are made from rare earth ores, mainly xenotime and euxenite (Wikipedia). The Wikipedia production section was not read in detail, so no process steps are given here.", "parts": [ { "name": "Erbium", "symbol": "Er", "role": "The whole material. The standard atomic weight is 167.259 in the Wikipedia infobox. Goodfellow foil is 99 % (2N) purity.", "atoms": 1, "atomic_weight": 167.259 } ] }, "risk_groups": [ { "title": "For people", "lead": "The hazard is in fine metal and dust. Sources disagree on the classification, and the toxicology is incompletely studied.", "points": [ { "label": "Fine metal", "line": "PubChem lists H228, flammable solid, with signal word Danger, for 93.3 % of reports. The Goodfellow foil sheet shows a flammable pictogram." }, { "label": "Dust", "line": "The Stanford Advanced Materials sheet says dust may cause asthma attacks and lung damage, including lung granulomas. It also says the toxicology has not been thoroughly investigated." }, { "label": "Acid", "line": "The same sheet says the metal reacts with dilute acids and emits flammable and explosive hydrogen gas." } ], "level": 1, "verdict": "Form-dependent" }, { "title": "If it fails", "lead": "The sources give three failure routes: a fire in fine metal, hydrogen release in acid, and slow tarnish in moist air.", "points": [ { "label": "Fire in fines", "line": "PubChem quotes Hawley that fine metal is flammable." }, { "label": "Acid", "line": "Hydrogen release on contact with dilute acids is flammable and explosive (Stanford Advanced Materials)." }, { "label": "Moist air and water", "line": "Wikipedia says erbium tarnishes slowly in moist air and reacts quite quickly with hot water." } ] }, { "title": "Handling and storage", "points": [ { "label": "Store dry", "line": "Keep in a cool, dry area in a tightly sealed container, and handle in a dry, controlled atmosphere (Stanford Advanced Materials)." }, { "label": "Fire", "line": "Use Class D or another metal extinguishing agent, and do not use water (Stanford Advanced Materials)." } ] } ] }, "updated": "2026-10-26", "review": { "status": "draft", "method": "assistant", "checked_values": 14, "unreachable": 3, "caveats": 6, "note": "Values were read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable: American Elements erbium page (HTTP 403), Fisher Scientific erbium page (timeout), UMN erbium safety data sheet (download failed). Caveats: the density values differ by up to 0.06 g/cm3 (Wikipedia 9.065, safety data sheet 9.01) and the boiling points by 5 °C; hardness values are ranges; the USGS supply figures are for the whole rare-earth group, not erbium; the hazard classifications differ between sources; corrosion entries are qualitative." }, "sources": { "usgs-rare-earths": { "title": "Mineral Commodity Summaries 2026: Rare Earths (USGS)", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "wikipedia-er": { "title": "Erbium (Wikipedia)", "url": "https://en.wikipedia.org/wiki/Erbium", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0 (cited, not reproduced)" }, "pubchem-er": { "title": "PubChem compound record: Erbium (CID 23980), including ECHA C&L Inventory classification", "id": "CAS 7440-52-0", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/23980", "kind": "database", "license": "PubChem (NCBI), public domain; sections attributed to ECHA and others" }, "sam-er-msds": { "title": "Material Safety Data Sheet: Erbium Metal (Stanford Advanced Materials, 2012), copy hosted by Sputtertargets.net", "url": "https://www.sputtertargets.net/Public/pdf/erbium-msds.pdf", "year": 2012, "kind": "datasheet", "license": "supplier safety data sheet, cited not reproduced" }, "goodfellow-er-foil": { "title": "Erbium foil light tight group (Goodfellow product datasheet, UK)", "url": "https://www.goodfellow.com/uk/erbium-foil-light-tight-group", "kind": "datasheet", "license": "supplier web page, cited not reproduced" }, "nict-edfa-frontiers": { "title": "Frontiers in Physics 2025: erbium-doped fibre amplifier for the CubeSOTA 6U CubeSat optical terminal (NICT)", "url": "https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2025.1542043/full", "year": 2025, "kind": "paper", "license": "open access, cited not reproduced" }, "agiltron-space-edfa": { "title": "Agiltron space-qualified erbium/ytterbium small signal fibre amplifier (product page)", "url": "https://agiltron.com/?p=22667", "kind": "web", "license": "vendor web page, cited not reproduced" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/erbium/" }