{
  "spore": "profile",
  "id": "lanthanum-oxide",
  "spore_version": "0.2",
  "family": "oxide-ceramics",
  "name": "Lanthanum oxide",
  "abbreviation": "La2O3",
  "role": "Rare-earth oxide used in optical glass and studied as a high-permittivity gate dielectric",
  "category": "ceramics",
  "type": "oxides",
  "summary": "Lanthanum(III) oxide (La2O3, CAS 1312-81-8) is a white powder with a density of 6.51 g/cm3 at 25 °C per the PubChem record. PubChem gives a melting point of 2304 °C, WebElements gives 2305 °C and a supplier listing gives 2315 °C. A 33 Angstrom La2O3 gate dielectric film gave an effective K value of 27 in a 2000 study by Wu et al. The oxide takes up water from humid air and converts to lanthanum hydroxide, so it has to be stored dry.\n",
  "best_for": "Optical glass additive, and research thin films for high-permittivity gate dielectrics kept in dry conditions",
  "weakest_at": "Moisture: lanthanum oxide converts to lanthanum hydroxide in humid air, and the hydroxide lowers permittivity",
  "identity": {
    "formula": "La2O3",
    "cas": "1312-81-8",
    "designations": [],
    "source": "nist-la2o3",
    "where": "NIST Chemistry WebBook entry: formula La 2 O 3 and CAS Registry Number 1312-81-8. The same CAS number appears on the PubChem record (CID 150906) and the Lorad listing."
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "optics-and-cameras",
      "electronics-and-chips"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, lanthanum(III) oxide (PubChem experimental value)",
      "value": 6.51,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C",
        "form": "not stated in the record"
      },
      "method": "Experimental density listed in the PubChem record; no measurement method given",
      "status": "ground",
      "source": "pubchem-la2o3",
      "where": "Chemical and Physical Properties, Experimental Properties, Density (6.51 @25 °C)",
      "source_detail": {
        "title": "PubChem compound record, Lanthanum sesquioxide (lanthanum oxide, CID 150906)",
        "id": "CID 150906; CAS 1312-81-8",
        "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/150906/JSON?heading=Experimental+Properties",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, dilanthanum trioxide (WebElements)",
      "value": 6500,
      "bound": "exact",
      "unit": "kg m-3",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "form": "not stated"
      },
      "method": "Compilation value on WebElements, assembled from the primary literature; no method given",
      "status": "ground",
      "source": "webelements-la2o3",
      "where": "Compound data, Density line (6500 kg m -3)",
      "source_detail": {
        "title": "WebElements, Dilanthanum trioxide (La2O3) compound data",
        "id": "WebElements compound page; no publication date printed (read 2026-11-02)",
        "url": "https://winter.group.shef.ac.uk/webelements/compounds/lanthanum/dilanthanum_trioxide.html",
        "year": 2026,
        "kind": "database",
        "license": "WebElements terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density (supplier listing)",
      "value": 6.51,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "form": "powder, as sold"
      },
      "method": "Supplier product listing; no test method given",
      "status": "ground",
      "note": "Reseller listing; it agrees with the PubChem value.",
      "source": "lorad-la2o3",
      "where": "Physical properties, Density line",
      "source_detail": {
        "title": "Lorad Chemical, Lanthanum oxide product listing (catalog LA-2565)",
        "id": "Catalog LA-2565; CAS 1312-81-8",
        "url": "https://loradchemical.com/products/lanthanum-oxide",
        "year": 2026,
        "kind": "web",
        "license": "supplier listing (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density (ChemicalBook listing, literature value)",
      "value": 6.51,
      "bound": "exact",
      "unit": "g/mL",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C",
        "basis": "literature value marked (lit.) on the page"
      },
      "method": "Chemical properties listing that cites the literature; no test method given",
      "status": "ground",
      "note": "Secondary listing; the same figure as PubChem.",
      "source": "chemicalbook-la2o3",
      "where": "Chemical Properties section, density line",
      "source_detail": {
        "title": "ChemicalBook, Lanthanum oxide CAS 1312-81-8: chemical properties, hazard information and uses",
        "id": "CAS 1312-81-8",
        "url": "https://chemicalbook.com/CASEN_1312-81-8.htm",
        "year": 2026,
        "kind": "web",
        "license": "listing aggregator (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point (PubChem experimental value)",
      "value": 2304,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "not stated in the record"
      },
      "method": "Experimental melting point listed in the PubChem record; no method given",
      "status": "ground",
      "source": "pubchem-la2o3",
      "where": "Chemical and Physical Properties, Experimental Properties, Melting Point (2304 °C)",
      "source_detail": {
        "title": "PubChem compound record, Lanthanum sesquioxide (lanthanum oxide, CID 150906)",
        "id": "CID 150906; CAS 1312-81-8",
        "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/150906/JSON?heading=Experimental+Properties",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point (WebElements)",
      "value": 2305,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "not stated"
      },
      "method": "Compilation value on WebElements; no method given",
      "status": "ground",
      "note": "Differs from the PubChem value by one degree; both are recorded, neither is averaged.",
      "source": "webelements-la2o3",
      "where": "Compound data, Melting point line (2305°C)",
      "source_detail": {
        "title": "WebElements, Dilanthanum trioxide (La2O3) compound data",
        "id": "WebElements compound page; no publication date printed (read 2026-11-02)",
        "url": "https://winter.group.shef.ac.uk/webelements/compounds/lanthanum/dilanthanum_trioxide.html",
        "year": 2026,
        "kind": "database",
        "license": "WebElements terms (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point (supplier listing)",
      "value": 2315,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "not stated"
      },
      "method": "Supplier product listing; no method given",
      "status": "ground",
      "note": "Higher than the PubChem and WebElements values. The Materion SDS gives no melting point (Not available).",
      "source": "lorad-la2o3",
      "where": "Physical properties, Melting Point line (2,315°C)",
      "source_detail": {
        "title": "Lorad Chemical, Lanthanum oxide product listing (catalog LA-2565)",
        "id": "Catalog LA-2565; CAS 1312-81-8",
        "url": "https://loradchemical.com/products/lanthanum-oxide",
        "year": 2026,
        "kind": "web",
        "license": "supplier listing (cited, not reproduced)"
      }
    },
    {
      "benchmark": "molecular_weight",
      "label": "Formula mass of La2O3",
      "value": 325.81,
      "bound": "exact",
      "unit": "g/mol",
      "scope": "material",
      "conditions": {
        "formula": "La2O3"
      },
      "method": "Formula mass printed on the supplier listing",
      "status": "calculated",
      "note": "Custom benchmark name, since no canonical molecular weight name was found. The NIST page prints 325.8091 with no unit, so that figure is not recorded.",
      "source": "lorad-la2o3",
      "where": "Physical properties, Formula Mass line (325.81 g/mol)",
      "source_detail": {
        "title": "Lorad Chemical, Lanthanum oxide product listing (catalog LA-2565)",
        "id": "Catalog LA-2565; CAS 1312-81-8",
        "url": "https://loradchemical.com/products/lanthanum-oxide",
        "year": 2026,
        "kind": "web",
        "license": "supplier listing (cited, not reproduced)"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat capacity, crystal form",
      "value": 0.333937,
      "bound": "exact",
      "unit": "J/(g·K)",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C",
        "phase": "crystal, printed as Cp(crystal)"
      },
      "method": "Listing value on ChemicalBook; no method given",
      "status": "ground",
      "source": "chemicalbook-la2o3",
      "where": "Chemical Properties section, Specific Heat Capacity line",
      "source_detail": {
        "title": "ChemicalBook, Lanthanum oxide CAS 1312-81-8: chemical properties, hazard information and uses",
        "id": "CAS 1312-81-8",
        "url": "https://chemicalbook.com/CASEN_1312-81-8.htm",
        "year": 2026,
        "kind": "web",
        "license": "listing aggregator (cited, not reproduced)"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Effective dielectric constant (K value) of a La2O3 gate dielectric",
      "value": 27,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "form": "thin film, 33 Angstrom La2O3 gate dielectric",
        "basis": "effective K value from the measured capacitance"
      },
      "method": "Capacitance measurement on a thin-film gate stack, as stated in the abstract",
      "status": "ground",
      "source": "wu2000",
      "where": "Abstract",
      "source_detail": {
        "title": "Electrical characteristics of high quality La2O3 gate dielectric (Wu et al., IEEE Electron Device Letters)",
        "id": "doi:10.1109/55.847374",
        "url": "https://ir.lib.nycu.edu.tw/handle/11536/30423",
        "year": 2000,
        "kind": "paper",
        "license": "repository record (abstract read)"
      }
    },
    {
      "benchmark": "dielectric_strength",
      "label": "Effective breakdown field of a La2O3 gate dielectric",
      "value": 13.5,
      "bound": "exact",
      "unit": "MV/cm",
      "scope": "material",
      "conditions": {
        "form": "thin film, 33 Angstrom La2O3 gate dielectric"
      },
      "method": "Breakdown measurement on a thin-film gate stack, as stated in the abstract",
      "status": "ground",
      "source": "wu2000",
      "where": "Abstract",
      "source_detail": {
        "title": "Electrical characteristics of high quality La2O3 gate dielectric (Wu et al., IEEE Electron Device Letters)",
        "id": "doi:10.1109/55.847374",
        "url": "https://ir.lib.nycu.edu.tw/handle/11536/30423",
        "year": 2000,
        "kind": "paper",
        "license": "repository record (abstract read)"
      }
    },
    {
      "benchmark": "equivalent_oxide_thickness",
      "label": "Equivalent oxide thickness of a La2O3 gate dielectric",
      "value": 4.8,
      "bound": "exact",
      "unit": "Angstrom",
      "scope": "material",
      "conditions": {
        "form": "thin film, 33 Angstrom La2O3 gate dielectric"
      },
      "method": "Derived in the source from the measured capacitance, as stated in the abstract",
      "status": "ground",
      "note": "Custom benchmark name, since no canonical name was found.",
      "source": "wu2000",
      "where": "Abstract",
      "source_detail": {
        "title": "Electrical characteristics of high quality La2O3 gate dielectric (Wu et al., IEEE Electron Device Letters)",
        "id": "doi:10.1109/55.847374",
        "url": "https://ir.lib.nycu.edu.tw/handle/11536/30423",
        "year": 2000,
        "kind": "paper",
        "license": "repository record (abstract read)"
      }
    },
    {
      "benchmark": "lattice_constant_a",
      "label": "Lattice constant a",
      "value": 0.394,
      "bound": "exact",
      "unit": "nm",
      "scope": "material",
      "conditions": {
        "crystal_system_as_printed": "trigonal",
        "space_group_as_printed": "P3m1",
        "note": "the Lorad listing gives the crystal system as hexagonal"
      },
      "method": "Crystallographic value as listed on ChemicalBook; no diffraction method given",
      "status": "ground",
      "note": "Custom benchmark name. Not checked against a diffraction paper.",
      "source": "chemicalbook-la2o3",
      "where": "Lattice constant line (a/nm, b/nm, c/nm)",
      "source_detail": {
        "title": "ChemicalBook, Lanthanum oxide CAS 1312-81-8: chemical properties, hazard information and uses",
        "id": "CAS 1312-81-8",
        "url": "https://chemicalbook.com/CASEN_1312-81-8.htm",
        "year": 2026,
        "kind": "web",
        "license": "listing aggregator (cited, not reproduced)"
      }
    },
    {
      "benchmark": "lattice_constant_c",
      "label": "Lattice constant c",
      "value": 0.613,
      "bound": "exact",
      "unit": "nm",
      "scope": "material",
      "conditions": {
        "crystal_system_as_printed": "trigonal",
        "space_group_as_printed": "P3m1",
        "note": "the Lorad listing gives the crystal system as hexagonal"
      },
      "method": "Crystallographic value as listed on ChemicalBook; no diffraction method given",
      "status": "ground",
      "note": "Custom benchmark name. Not checked against a diffraction paper.",
      "source": "chemicalbook-la2o3",
      "where": "Lattice constant line (a/nm, b/nm, c/nm)",
      "source_detail": {
        "title": "ChemicalBook, Lanthanum oxide CAS 1312-81-8: chemical properties, hazard information and uses",
        "id": "CAS 1312-81-8",
        "url": "https://chemicalbook.com/CASEN_1312-81-8.htm",
        "year": 2026,
        "kind": "web",
        "license": "listing aggregator (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Humid air or water vapour at room temperature",
      "headline": "Lanthanum oxide reacts with water vapour and converts to lanthanum hydroxide, within a day in the powders studied.",
      "effect": "Fleming et al. (2010) report that the powders hydroxylate to La(OH)3 at room temperature, and that '24 h of exposure to atmosphere is generally sufficient to cause complete hydroxylation at room temperature'. The reaction rate was related to crystallite size. A smaller amount of an oxycarbonate, La2O2CO3, also forms after air exposure.",
      "rating": "moderate",
      "conditions": {
        "exposure": "powders of several lanthana types exposed to air or water vapour at room temperature",
        "time": "up to 24 h reported in the abstract"
      },
      "source": "fleming2010",
      "where": "Abstract"
    },
    {
      "environment": "Dilute acid solutions",
      "headline": "ChemicalBook lists lanthanum oxide as soluble in dilute acid solutions; no corrosion test in acid was read.",
      "effect": "ChemicalBook's solubility line reads 'insoluble in H2O; soluble in dilute acid solutions'. The Lorad listing gives only 'Insoluble' for water and does not mention acids. This is a solubility statement, not a corrosion test.",
      "rating": "unknown",
      "conditions": {
        "basis": "solubility statement on a supplier listing",
        "acid": "not named on the page"
      },
      "source": "chemicalbook-la2o3",
      "where": "Chemical Properties section, solubility line"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem GHS summary for lanthanum oxide: signal word Warning, with notified hazard statements H315 (causes skin irritation), H319 (causes serious eye irritation) and H335 (may cause respiratory irritation). The record also says 'This chemical does not meet GHS hazard criteria for 59.9% (370 of 618) of all reports.'",
        "ghs": [
          "H315",
          "H319",
          "H335"
        ],
        "source": "pubchem-ghs",
        "where": "Safety and Hazards, GHS Classification (CID 150906)"
      },
      {
        "text": "Materion safety data sheet, SDS L-MSDS0026 (revision 07-14-2015): the product 'does not meet the criteria for classification'. Eye contact may cause temporary irritation. Gases hazardous to health may form in a fire.",
        "ghs": [],
        "source": "materion-sds",
        "where": "Sections 2, 5 and 11"
      },
      {
        "text": "ChemicalBook prints an oral toxicity figure for lanthanum oxide: 'Oral toxicity (rabbit LD50): > 9968 mg/kg'. The page does not name the test standard.",
        "ghs": [],
        "source": "chemicalbook-la2o3",
        "where": "Hazard information, oral toxicity line"
      }
    ],
    "failure_risks": [
      {
        "mode": "Hydroxide formation from moisture",
        "trigger": "Storage or handling in humid air, or exposure to water vapour",
        "consequence": "The oxide hydroxylates to La(OH)3 at room temperature. The abstract says 24 h of exposure to atmosphere is generally sufficient for complete hydroxylation.",
        "severity": "moderate",
        "source": "fleming2010",
        "where": "Abstract"
      },
      {
        "mode": "Loss of permittivity in a gate dielectric",
        "trigger": "A hygroscopic La2O3 film exposed to moisture, forming La(OH)3",
        "consequence": "Hande et al. state that the hygroscopic nature of La2O3 forms lanthanum hydroxide, which causes deterioration of electrical properties such as permittivity. The same abstract gives a dielectric constant of about 27 for La2O3.",
        "severity": "moderate",
        "source": "hande2008",
        "where": "Abstract, first paragraph"
      }
    ],
    "side_effects": [
      {
        "text": "Air exposure also forms a smaller amount of an oxycarbonate, La2O2CO3, which the authors say is stable to hydroxylation.",
        "affects": "Composition of the powder",
        "source": "fleming2010",
        "where": "Abstract"
      }
    ],
    "handling": [
      {
        "text": "Store in the original tightly closed container, away from incompatible materials, and use care in handling.",
        "source": "materion-sds",
        "where": "Sections 7 and 10"
      },
      {
        "text": "Wear safety glasses with side shields (or goggles) and chemical-resistant gloves when handling the powder.",
        "source": "materion-sds",
        "where": "Section 8"
      }
    ],
    "mitigations": [
      {
        "text": "ChemicalBook lists the material as hygroscopic and sensitive to moisture, so store it sealed and dry.",
        "source": "chemicalbook-la2o3",
        "where": "Chemical Properties section, sensitivity line"
      }
    ]
  },
  "uses": [
    {
      "application": "optics-and-cameras",
      "device": "Optical glass for camera lenses",
      "example": "ChemicalBook's uses section says lanthanum oxide is used in the manufacture of optical glasses, and that lanthanum raises refractive index and lowers dispersion in the glass.",
      "source": "chemicalbook-la2o3",
      "where": "Uses section"
    },
    {
      "application": "electronics-and-chips",
      "device": "High-permittivity gate dielectric in research transistors",
      "example": "Wu et al. (2000) report an effective K value of 27 for a 33 Angstrom La2O3 gate dielectric, with an equivalent oxide thickness of 4.8 Angstrom and an effective breakdown field of 13.5 MV/cm.",
      "source": "wu2000",
      "where": "Abstract"
    }
  ],
  "supply": [
    {
      "subject": "Lanthanum, from rare-earth mine output",
      "producers": [
        {
          "country": "China",
          "share_percent": 69.2,
          "year": 2025
        },
        {
          "country": "United States",
          "share_percent": 13.1,
          "year": 2025
        },
        {
          "country": "Australia",
          "share_percent": 7.4,
          "year": 2025
        },
        {
          "country": "Burma",
          "share_percent": 5.6,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 List of Critical Minerals (lanthanum is listed as a rare earth entry, used in chemical catalysts, metallurgy and batteries)",
          "listed": true
        },
        {
          "list": "EU critical raw materials list, which names light rare earth elements (Regulation (EU) 2024/1252, as shown on the European Commission page)",
          "listed": true
        }
      ],
      "recycling": "USGS: limited quantities of rare earths were recovered from batteries, permanent magnets and fluorescent lamps in 2025.",
      "substitutes": [
        "USGS: substitutes are available for many rare-earth applications but generally are less effective."
      ],
      "source": "usgs-mcs2026-rare-earths",
      "where": "World Mine Production and Reserves table, 2025e, rare-earth oxide equivalent (REO). Shares are calculated by Space Mushroom from the country figures and the rounded world total of 390,000 t. The table covers all rare earths, not lanthanum oxide alone. Recycling and Substitutes sections."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Materion Advanced Chemicals safety data sheet: Lanthanum oxide (La2O3), SDS L-MSDS0026",
      "type": "sds",
      "url": "https://www.physics.purdue.edu/primelab/safety/MSDS/SDS/lanthanum%20oxide%20%20-%20Materion.pdf",
      "year": 2015
    },
    {
      "title": "PubChem: Lanthanum sesquioxide (CID 150906), experimental properties and GHS classification",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/150906",
      "year": 2026
    },
    {
      "title": "WebElements: Dilanthanum trioxide compound data",
      "type": "database",
      "url": "https://winter.group.shef.ac.uk/webelements/compounds/lanthanum/dilanthanum_trioxide.html",
      "year": 2026
    },
    {
      "title": "NIST Chemistry WebBook: lanthanum oxide",
      "type": "database",
      "url": "https://webbook.nist.gov/cgi/cbook.cgi?ID=C1312818&Mask=1",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Rare Earths",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf",
      "year": 2026
    },
    {
      "title": "Lorad Chemical: Lanthanum oxide product listing (catalog LA-2565)",
      "type": "datasheet",
      "url": "https://loradchemical.com/products/lanthanum-oxide",
      "year": 2026
    },
    {
      "title": "ChemicalBook: Lanthanum oxide, CAS 1312-81-8, chemical properties and uses",
      "type": "datasheet",
      "url": "https://chemicalbook.com/CASEN_1312-81-8.htm",
      "year": 2026
    },
    {
      "title": "Fleming et al., The rapid formation of La(OH)3 from La2O3 powders on exposure to water vapor (J. Am. Ceram. Soc. 93, 1187-1194)",
      "type": "paper",
      "url": "https://research.ucc.ie/en/publications/the-rapid-formation-of-laohsub3sub-from-lasub2subosub3sub-powders/",
      "year": 2010
    },
    {
      "title": "Wu et al., Electrical characteristics of La2O3 gate dielectric (IEEE Electron Device Letters, 2000)",
      "type": "paper",
      "url": "https://ir.lib.nycu.edu.tw/handle/11536/30423",
      "year": 2000
    },
    {
      "title": "Hande et al., Atomic Layer Deposition of Lanthanum Based Oxides for High-K Gate Dielectrics (AVS 55th Symposium, abstract TF-ThP17)",
      "type": "paper",
      "url": "https://www2.avs.org/symposium2008/Papers/Paper_TF-ThP17.html",
      "year": 2008
    }
  ],
  "gaps": [
    "Melting point is not settled: PubChem gives 2304 °C, WebElements 2305 °C and the Lorad listing 2315 °C. The Materion SDS gives Not available. No primary measurement paper was read in this run.",
    "No refractive index value with wavelength and temperature was found in a source read in this run. The Lorad page's refractive-index line was not legible in the page text, so it is not recorded.",
    "The crystal system is not agreed: ChemicalBook says trigonal (space group P3m1), Lorad says hexagonal. The lattice constants come from ChemicalBook only.",
    "No vacuum, radiation, thermal-cycling or flight result for lanthanum oxide was found in any source read.",
    "The acute oral toxicity figure comes from ChemicalBook alone, and the page does not name the species or test standard.",
    "Crustal abundance of lanthanum was not found in a source read in this run.",
    "No UNS, EN, ASTM or other grade designation applies to lanthanum oxide in the sources read; CAS 1312-81-8 is the identifier used.",
    "The manufacturing route (for example calcination of a carbonate or oxalate precursor) is not described in any source read in this run.",
    "Goodfellow, Alfa Aesar and Acros product sheets were named on ChemicalBook but were not reached in this run, so no grade purity figure is recorded.",
    "The USGS 2025 critical-minerals page refused automated fetching in this run. The lanthanum entry was read through a web-fetch summary, so check it before relying on it.",
    "Only one thin-film study (Wu et al., 2000) gives a dielectric constant and breakdown field. No second study with an independent value was read."
  ],
  "story": {
    "why": "Lanthanum oxide (La2O3) is a white rare-earth oxide. It is used in optical glass for lenses, where the lanthanum raises the refractive index. It is also studied as a high-permittivity gate dielectric in research transistors, with an effective K value of 27 in one thin-film study. The oxide is hygroscopic, meaning it takes up water from air, so it has to be stored dry.",
    "uses": [
      {
        "where": "Optical glass",
        "line": "ChemicalBook says lanthanum oxide is used in the manufacture of optical glasses, and that lanthanum raises the refractive index and lowers dispersion."
      },
      {
        "where": "Research gate dielectrics",
        "line": "Wu et al. (2000) report an effective K value of 27 for a 33 Angstrom La2O3 film, with an equivalent oxide thickness of 4.8 Angstrom and an effective breakdown field of 13.5 MV/cm."
      },
      {
        "where": "Other listed uses",
        "line": "ChemicalBook also lists fast ion conductors, X-ray intensifying screens, phosphors and catalysts as uses. Each is a secondary listing, and no source for each was read in this run."
      }
    ],
    "can_do": [
      {
        "label": "High-permittivity film",
        "line": "Acts as a thin-film dielectric with an effective K value of 27 for a 33 Angstrom film in the 2000 study by Wu et al.",
        "benchmark": "dielectric_constant",
        "scope": "material"
      },
      {
        "label": "Breakdown field",
        "line": "Withstands an effective breakdown field of 13.5 MV/cm in that thin-film test, per the same abstract.",
        "benchmark": "dielectric_strength",
        "scope": "material"
      },
      {
        "label": "Dry storage",
        "line": "Stays a stable solid in dry storage: the Materion SDS calls the material stable under normal conditions.",
        "scope": "material"
      },
      {
        "label": "Lattice",
        "line": "Lists a lattice with a of 0.394 nm and c of 0.613 nm per ChemicalBook. The crystal system is disputed between sources.",
        "benchmark": "lattice_constant_a",
        "scope": "material"
      }
    ],
    "compare": "This record gives lanthanum oxide's density and melting point, but it holds no side-by-side values for other oxides, so the comparison below is qualitative. The melting point differs by source, from 2304 °C in PubChem to 2315 °C in a supplier listing, and both are kept. The dielectric constant of 27 comes from a single thin-film study, so it should be read as one measurement rather than a settled figure.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Melting point",
        "benchmark": "melting_point",
        "scope": "material"
      },
      {
        "label": "Dielectric constant (thin film)",
        "benchmark": "dielectric_constant",
        "scope": "material"
      }
    ],
    "handling": [
      "Store in the original tightly closed container, away from incompatible materials (Materion SDS).",
      "Wear safety glasses with side shields or goggles when handling the powder (Materion SDS).",
      "Keep the container sealed: the oxide is hygroscopic and forms hydroxide and carbonate species in moist air."
    ],
    "good_for": [
      "Optical glass additive, where lanthanum raises the refractive index (ChemicalBook).",
      "Research into high-permittivity gate dielectrics, processed and stored dry (Wu et al., 2000; Hande et al., 2008)."
    ],
    "watch_out": [
      "Moisture: the oxide converts to lanthanum hydroxide, which lowers permittivity in thin films (Hande et al., 2008).",
      "Air exposure also forms an oxycarbonate, La2O2CO3 (Fleming et al., 2010).",
      "The melting point differs between sources, from 2304 °C to 2315 °C."
    ],
    "verdict": "Lanthanum oxide suits optical glass and high-permittivity research films, but it needs dry storage. Most of its physical data come from database and supplier listings rather than a measurement paper.",
    "recipe": {
      "line": "Lanthanum(III) oxide is made of two lanthanum atoms and three oxygen atoms per formula unit, La2O3. The sources read in this run do not describe how it is made, so no manufacturing process is given.",
      "parts": [
        {
          "name": "Lanthanum",
          "symbol": "La",
          "role": "The rare-earth metal in the oxide. In La2O3 it is present as lanthanum(III), the oxidation state WebElements prints for dilanthanum trioxide."
        },
        {
          "name": "Oxygen",
          "symbol": "O",
          "role": "Bonded to the lanthanum in the oxide lattice. In moist air the oxide also takes up water and carbon dioxide to form hydroxide and carbonate species."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The Materion safety data sheet does not classify the powder. PubChem's aggregated notifications list skin, eye and airway irritation for a share of reports, so treat the powder as an irritant.",
        "points": [
          {
            "label": "The powder",
            "line": "The Materion safety data sheet states that the product does not meet the criteria for classification. Eye contact may cause temporary irritation."
          },
          {
            "label": "Dust, skin and eyes",
            "line": "PubChem lists H315 (skin irritation), H319 (serious eye irritation) and H335 (may cause respiratory irritation). The same record says the chemical does not meet GHS hazard criteria for 59.9% (370 of 618) of all reports."
          },
          {
            "label": "Swallowing",
            "line": "ChemicalBook prints an oral toxicity figure of greater than 9968 mg/kg in rabbits. That secondary listing does not name the test standard."
          }
        ],
        "level": 0,
        "verdict": "Not classified by the SDS; PubChem notes irritation"
      },
      {
        "title": "In a fire",
        "lead": "The Materion safety data sheet warns that gases hazardous to health may form in a fire. It names no specific decomposition products.",
        "points": [
          {
            "label": "Fire response",
            "line": "The SDS advises water spray to cool unopened containers and suitable protective equipment for firefighters."
          }
        ],
        "verdict": "Gases hazardous to health may form in a fire"
      },
      {
        "title": "Moisture",
        "lead": "Lanthanum oxide takes up water from humid air and converts to lanthanum hydroxide. In the Fleming et al. study this happened rapidly at room temperature.",
        "points": [
          {
            "label": "Hydroxide",
            "line": "Fleming et al. (2010) report that the powders hydroxylate to form La(OH)3 at room temperature. Complete hydroxylation was generally reached after 24 h of exposure to air."
          },
          {
            "label": "Gate dielectrics",
            "line": "Hande et al. (2008) state that the hydroxide that forms from La2O3 lowers its permittivity."
          }
        ],
        "verdict": "Hygroscopic: it turns into hydroxide in humid air"
      }
    ]
  },
  "updated": "2026-11-02",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 14,
    "unreachable": 1,
    "caveats": 2,
    "note": "Written by an AI assistant on 2026-11-02 from pages read in this run. Values come from database, supplier and abstract pages; no primary melting-point measurement was read. The Lorad listing blocks automated fetching, so its three values (density, melting point and formula mass) were read with a web fetch in this run and could not be re-matched by the verifier. The USGS 2025 critical-minerals page could not be fetched directly."
  },
  "sources": {
    "pubchem-la2o3": {
      "title": "PubChem compound record, Lanthanum sesquioxide (lanthanum oxide, CID 150906)",
      "id": "CID 150906; CAS 1312-81-8",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/150906/JSON?heading=Experimental+Properties",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NCBI)"
    },
    "pubchem-ghs": {
      "title": "PubChem compound record, Lanthanum sesquioxide (CID 150906), GHS classification section",
      "id": "CID 150906; aggregated GHS notifications from ECHA C&L",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/150906/JSON?heading=GHS+Classification",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NCBI)"
    },
    "webelements-la2o3": {
      "title": "WebElements, Dilanthanum trioxide (La2O3) compound data",
      "id": "WebElements compound page; no publication date printed (read 2026-11-02)",
      "url": "https://winter.group.shef.ac.uk/webelements/compounds/lanthanum/dilanthanum_trioxide.html",
      "year": 2026,
      "kind": "database",
      "license": "WebElements terms (cited, not reproduced)"
    },
    "lorad-la2o3": {
      "title": "Lorad Chemical, Lanthanum oxide product listing (catalog LA-2565)",
      "id": "Catalog LA-2565; CAS 1312-81-8",
      "url": "https://loradchemical.com/products/lanthanum-oxide",
      "year": 2026,
      "kind": "web",
      "license": "supplier listing (cited, not reproduced)"
    },
    "chemicalbook-la2o3": {
      "title": "ChemicalBook, Lanthanum oxide CAS 1312-81-8: chemical properties, hazard information and uses",
      "id": "CAS 1312-81-8",
      "url": "https://chemicalbook.com/CASEN_1312-81-8.htm",
      "year": 2026,
      "kind": "web",
      "license": "listing aggregator (cited, not reproduced)"
    },
    "nist-la2o3": {
      "title": "NIST Chemistry WebBook, SRD 69: lanthanum oxide",
      "id": "CAS 1312-81-8; formula La 2 O 3",
      "url": "https://webbook.nist.gov/cgi/cbook.cgi?ID=C1312818&Mask=1",
      "year": 2026,
      "kind": "database",
      "license": "NIST Standard Reference Data (cited)"
    },
    "materion-sds": {
      "title": "Materion Advanced Chemicals, Safety Data Sheet: Lanthanum oxide (La2O3)",
      "id": "SDS L-MSDS0026, version 03, revision 07-14-2015",
      "url": "https://www.physics.purdue.edu/primelab/safety/MSDS/SDS/lanthanum%20oxide%20%20-%20Materion.pdf",
      "year": 2015,
      "kind": "datasheet",
      "license": "supplier document (cited, not reproduced)"
    },
    "usgs-mcs2026-rare-earths": {
      "title": "Mineral Commodity Summaries 2026, Rare Earths (USGS)",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-crit2025": {
      "title": "About the 2025 List of Critical Minerals (USGS)",
      "id": "Final 2025 List of Critical Minerals",
      "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals",
      "year": 2025,
      "kind": "web",
      "license": "public domain (USGS)"
    },
    "ec-crm": {
      "title": "Critical raw materials (European Commission, Regulation (EU) 2024/1252)",
      "id": "Regulation (EU) 2024/1252",
      "url": "https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en",
      "year": 2024,
      "kind": "web",
      "license": "European Commission web page"
    },
    "fleming2010": {
      "title": "The rapid formation of La(OH)3 from La2O3 powders on exposure to water vapor",
      "id": "doi:10.1111/j.1551-2916.2009.03564.x (J. Am. Ceram. Soc. 93(4), 1187-1194)",
      "url": "https://research.ucc.ie/en/publications/the-rapid-formation-of-laohsub3sub-from-lasub2subosub3sub-powders/",
      "year": 2010,
      "kind": "paper",
      "license": "publisher record (abstract read)"
    },
    "hande2008": {
      "title": "Atomic Layer Deposition of Lanthanum Based Oxides for High-K Gate Dielectrics (AVS 55th International Symposium, paper TF-ThP17)",
      "id": "AVS 2008, Thursday session TF-ThP, presenter A. Hande",
      "url": "https://www2.avs.org/symposium2008/Papers/Paper_TF-ThP17.html",
      "year": 2008,
      "kind": "paper",
      "license": "conference abstract (cited)"
    },
    "wu2000": {
      "title": "Electrical characteristics of high quality La2O3 gate dielectric (Wu et al., IEEE Electron Device Letters)",
      "id": "doi:10.1109/55.847374",
      "url": "https://ir.lib.nycu.edu.tw/handle/11536/30423",
      "year": 2000,
      "kind": "paper",
      "license": "repository record (abstract read)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/lanthanum-oxide/"
}