{
  "spore": "profile",
  "id": "lanthanum",
  "spore_version": "0.2",
  "family": "rare-earth-metals",
  "name": "Lanthanum",
  "abbreviation": "La",
  "role": "optical-glass and battery-alloy rare-earth metal; LaB6 thermionic emitter in electric-propulsion cathodes",
  "category": "metals",
  "type": "heavy-metals",
  "summary": "Lanthanum is the element La, a silvery rare-earth metal with a density of 6.145 g/cm3 at 20 °C (Wikipedia) and a melting point of 920 °C. It makes up 39 mg/kg of the Earth's crust (Wikipedia) and is mined together with the other rare earths, where China produced 270,000 of 390,000 t in 2025 (USGS). Its main uses are as lanthanum oxide in high-index optical glass and as an alloy component in nickel-metal-hydride battery anodes. The metal tarnishes in air within hours and reacts with water and acids to release flammable hydrogen, so it is classed as a flammable solid and is kept under argon. A NASA record describes lanthanum hexaboride (a compound, not the metal) as a thermionic emitter in Hall-thruster hollow cathodes.\n",
  "best_for": "Optical glass and camera-lens additive (lanthanum oxide, high refractive index), and LaB6 emitters in Hall-thruster cathodes (Wikipedia; NASA Tech Briefs 2010)",
  "weakest_at": "Handling: a flammable solid that tarnishes in air within hours and releases hydrogen with water and acids (ESPI, Lesker, Wikipedia)",
  "identity": {
    "formula": "La (element); lanthanum metal, 100 % La in the Lesker and ESPI sheets",
    "cas": "7439-91-0",
    "designations": [],
    "source": "pubchem-la",
    "where": "Other Identifiers, CAS entry (PubChem CID 23926); CAS 7439-91-0 and EC number 231-099-0 are also printed in the ESPI SDS, Section 3"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "optics-and-cameras",
      "propulsion-and-tanks",
      "batteries"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, lanthanum at 20 °C (Wikipedia)",
      "value": 6.145,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "temperature": "20 °C",
        "unit_in_source": "6.145 g/cm3 (at 20 °C)"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Density (at 20 °C) 6.145 g/cm3",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, lanthanum at 25 °C (PubChem experimental)",
      "value": 6.166,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C"
      },
      "method": "Experimental property printed in the PubChem record",
      "status": "ground",
      "source": "pubchem-la",
      "where": "Chemical and Physical Properties, Experimental Properties, Density 6.166 @25 °C",
      "source_detail": {
        "title": "PubChem compound record: Lanthanum (CID 23926), including ECHA C&L Inventory classification",
        "id": "CAS 7439-91-0",
        "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23926/JSON",
        "year": 2026,
        "kind": "database",
        "license": "PubChem (NCBI), public domain; sections attributed to ECHA and others"
      }
    },
    {
      "benchmark": "density",
      "label": "Relative density, lanthanum solid (ESPI SDS)",
      "value": 6.17,
      "bound": "exact",
      "unit": "g/cc",
      "scope": "material",
      "conditions": {
        "temperature": "20 °C",
        "form": "solid pieces, as sold for scientific research"
      },
      "method": "Value printed in the supplier safety data sheet",
      "status": "ground",
      "source": "espi-la-sds",
      "where": "Section 9, Relative Density (Specific Gravity) 6.17 g/cc at 20 °C",
      "source_detail": {
        "title": "Safety data sheet: Lanthanum solid (ESPI Metals)",
        "id": "CAS 7439-91-0; EC 231-099-0",
        "url": "https://www.espimetals.com/index.php/msds/500-lanthanum-msds",
        "kind": "datasheet",
        "license": "supplier safety data sheet, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density of solid, lanthanum (WebElements)",
      "value": 6146,
      "bound": "exact",
      "unit": "kg/m3",
      "scope": "material",
      "conditions": {
        "temperature": "not stated"
      },
      "method": "Value printed on the WebElements physical-properties page",
      "status": "ground",
      "source": "webelements-la",
      "where": "Density properties, row Density (of solid) 6146 kg m-3",
      "source_detail": {
        "title": "WebElements: Lanthanum, physical properties (University of Sheffield)",
        "url": "https://winter.group.shef.ac.uk/webelements/lanthanum/physics.html",
        "kind": "database",
        "license": "WebElements, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, lanthanum (Wikipedia)",
      "value": 920,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "pressure": "not stated",
        "unit_in_source": "1193 K (920 °C, 1688 °F)"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Melting point, 1193 K (920 °C, 1688 °F)",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, lanthanum (PubChem)",
      "value": 920,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "pressure": "not stated"
      },
      "method": "Experimental property printed in the PubChem record",
      "status": "ground",
      "source": "pubchem-la",
      "where": "Chemical and Physical Properties, Experimental Properties, Melting Point 920 °C",
      "source_detail": {
        "title": "PubChem compound record: Lanthanum (CID 23926), including ECHA C&L Inventory classification",
        "id": "CAS 7439-91-0",
        "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23926/JSON",
        "year": 2026,
        "kind": "database",
        "license": "PubChem (NCBI), public domain; sections attributed to ECHA and others"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, lanthanum solid (ESPI SDS)",
      "value": 918,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "solid"
      },
      "method": "Value printed in the supplier safety data sheet",
      "status": "ground",
      "note": "The sources give 918 to 921 °C. All are entered with their own source, and none has been averaged.",
      "source": "espi-la-sds",
      "where": "Section 9, Melting Point 918 °C",
      "source_detail": {
        "title": "Safety data sheet: Lanthanum solid (ESPI Metals)",
        "id": "CAS 7439-91-0; EC 231-099-0",
        "url": "https://www.espimetals.com/index.php/msds/500-lanthanum-msds",
        "kind": "datasheet",
        "license": "supplier safety data sheet, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, lanthanum metal (Lesker MSDS, 1991)",
      "value": 921,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "silver solid pieces or powder"
      },
      "method": "Value printed in the 1991 supplier safety data sheet",
      "status": "ground",
      "source": "lesker-la-msds",
      "where": "Section III Physical Data, Melting Point (oC) 921oC",
      "source_detail": {
        "title": "Kurt J. Lesker Company material safety data sheet: Lanthanum metal (6/25/91)",
        "id": "CAS 7439-91-0",
        "url": "https://www.lesker.com/newweb/deposition_materials/pdf/msds_la.pdf",
        "year": 1991,
        "kind": "datasheet",
        "license": "supplier safety data sheet, cited not reproduced"
      }
    },
    {
      "benchmark": "boiling_point",
      "label": "Boiling point, lanthanum (Wikipedia)",
      "value": 3464,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "pressure": "not stated",
        "unit_in_source": "3737 K (3464 °C, 6267 °F)"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Boiling point, 3737 K (3464 °C, 6267 °F)",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "boiling_point",
      "label": "Boiling point, lanthanum (PubChem)",
      "value": 3464,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "pressure": "760 mmHg"
      },
      "method": "Experimental property printed in the PubChem record",
      "status": "ground",
      "source": "pubchem-la",
      "where": "Chemical and Physical Properties, Experimental Properties, Boiling Point 3464 °C @760 mm Hg",
      "source_detail": {
        "title": "PubChem compound record: Lanthanum (CID 23926), including ECHA C&L Inventory classification",
        "id": "CAS 7439-91-0",
        "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23926/JSON",
        "year": 2026,
        "kind": "database",
        "license": "PubChem (NCBI), public domain; sections attributed to ECHA and others"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat capacity, lanthanum (Wikipedia)",
      "value": 195.162,
      "bound": "exact",
      "unit": "J/(kg·K)",
      "scope": "material",
      "conditions": {
        "temperature": "not stated in the infobox"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Specific heat capacity 195.162 J/(kg·K)",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, lanthanum (Wikipedia)",
      "value": 13.4,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "not stated in the infobox"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Thermal conductivity 13.4 W/(m⋅K)",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity, lanthanum (WebElements)",
      "value": 13,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "temperature": "not stated"
      },
      "method": "Value printed on the WebElements physical-properties page",
      "status": "ground",
      "source": "webelements-la",
      "where": "Heat and conduction, row Thermal conductivity 13 W m-1 K-1",
      "source_detail": {
        "title": "WebElements: Lanthanum, physical properties (University of Sheffield)",
        "url": "https://winter.group.shef.ac.uk/webelements/lanthanum/physics.html",
        "kind": "database",
        "license": "WebElements, cited not reproduced"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion, lanthanum (Wikipedia)",
      "value": 5.1,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "temperature": "20 °C",
        "unit_in_source": "5.1×10−6/K (at 20 °C)"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Thermal expansion, 5.1×10−6/K (at 20 °C)",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, lanthanum alpha form (Wikipedia)",
      "value": 36.6,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated in the infobox",
        "form": "alpha form, double hexagonal close-packed (dhcp)"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Young's modulus, alpha form 36.6 GPa",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, lanthanum (WebElements)",
      "value": 37,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated"
      },
      "method": "Value printed on the WebElements physical-properties page",
      "status": "ground",
      "source": "webelements-la",
      "where": "Elastic properties, row Young's modulus 37 GPa",
      "source_detail": {
        "title": "WebElements: Lanthanum, physical properties (University of Sheffield)",
        "url": "https://winter.group.shef.ac.uk/webelements/lanthanum/physics.html",
        "kind": "database",
        "license": "WebElements, cited not reproduced"
      }
    },
    {
      "benchmark": "shear_modulus",
      "label": "Shear modulus, lanthanum alpha form (Wikipedia)",
      "value": 14.3,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated in the infobox",
        "form": "alpha form, double hexagonal close-packed (dhcp)"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Shear modulus, alpha form 14.3 GPa",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "shear_modulus",
      "label": "Rigidity (shear) modulus, lanthanum (WebElements)",
      "value": 14,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated"
      },
      "method": "Value printed on the WebElements physical-properties page",
      "status": "ground",
      "source": "webelements-la",
      "where": "Elastic properties, row Rigidity modulus 14 GPa",
      "source_detail": {
        "title": "WebElements: Lanthanum, physical properties (University of Sheffield)",
        "url": "https://winter.group.shef.ac.uk/webelements/lanthanum/physics.html",
        "kind": "database",
        "license": "WebElements, cited not reproduced"
      }
    },
    {
      "benchmark": "bulk_modulus",
      "label": "Bulk modulus, lanthanum alpha form (Wikipedia)",
      "value": 27.9,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated in the infobox",
        "form": "alpha form, double hexagonal close-packed (dhcp)"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Bulk modulus, alpha form 27.9 GPa",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "bulk_modulus",
      "label": "Bulk modulus, lanthanum (WebElements)",
      "value": 28,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated"
      },
      "method": "Value printed on the WebElements physical-properties page",
      "status": "ground",
      "source": "webelements-la",
      "where": "Elastic properties, row Bulk modulus 28 GPa",
      "source_detail": {
        "title": "WebElements: Lanthanum, physical properties (University of Sheffield)",
        "url": "https://winter.group.shef.ac.uk/webelements/lanthanum/physics.html",
        "kind": "database",
        "license": "WebElements, cited not reproduced"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "label": "Poisson's ratio, lanthanum alpha form (Wikipedia)",
      "value": 0.28,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "temperature": "not stated in the infobox",
        "form": "alpha form, double hexagonal close-packed (dhcp)"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Poisson ratio, alpha form 0.280",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "poissons_ratio",
      "label": "Poisson's ratio, lanthanum (WebElements)",
      "value": 0.28,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "temperature": "not stated"
      },
      "method": "Value printed on the WebElements physical-properties page",
      "status": "ground",
      "source": "webelements-la",
      "where": "Elastic properties, row Poisson's ratio 0.28 (no units)",
      "source_detail": {
        "title": "WebElements: Lanthanum, physical properties (University of Sheffield)",
        "url": "https://winter.group.shef.ac.uk/webelements/lanthanum/physics.html",
        "kind": "database",
        "license": "WebElements, cited not reproduced"
      }
    },
    {
      "benchmark": "brinell_hardness",
      "label": "Brinell hardness, lanthanum (WebElements)",
      "value": 363,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "unit_in_source": "363 MN m-2"
      },
      "method": "Value printed on the WebElements physical-properties page, given as MN m-2 (equal to MPa)",
      "status": "ground",
      "note": "No canonical name exists for hardness in the property file, so brinell_hardness is a new name and is listed in gaps.",
      "source": "webelements-la",
      "where": "Hardnesses, row Brinell hardness 363 MN m-2",
      "source_detail": {
        "title": "WebElements: Lanthanum, physical properties (University of Sheffield)",
        "url": "https://winter.group.shef.ac.uk/webelements/lanthanum/physics.html",
        "kind": "database",
        "license": "WebElements, cited not reproduced"
      }
    },
    {
      "benchmark": "brinell_hardness",
      "label": "Brinell hardness range, lanthanum (Wikipedia)",
      "value": 350,
      "value_high": 400,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated in the infobox",
        "note_on_range": "the infobox gives a range, not a single test value"
      },
      "method": "Range printed in the Wikipedia infobox",
      "status": "ground",
      "note": "No canonical name exists for hardness, so brinell_hardness is a new name and is listed in gaps. The range is given by Wikipedia without test conditions.",
      "source": "wikipedia-la",
      "where": "Infobox, row Brinell hardness 350–400 MPa",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    },
    {
      "benchmark": "vickers_hardness",
      "label": "Vickers hardness, lanthanum (WebElements)",
      "value": 491,
      "bound": "exact",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "temperature": "not stated",
        "unit_in_source": "491 MN m-2"
      },
      "method": "Value printed on the WebElements physical-properties page, given as MN m-2 (equal to MPa)",
      "status": "ground",
      "note": "No canonical name exists for hardness, so vickers_hardness is a new name and is listed in gaps.",
      "source": "webelements-la",
      "where": "Hardnesses, row Vickers hardness 491 MN m-2",
      "source_detail": {
        "title": "WebElements: Lanthanum, physical properties (University of Sheffield)",
        "url": "https://winter.group.shef.ac.uk/webelements/lanthanum/physics.html",
        "kind": "database",
        "license": "WebElements, cited not reproduced"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "label": "Electrical resistivity, lanthanum alpha polycrystalline form (Wikipedia)",
      "value": 615,
      "bound": "exact",
      "unit": "nΩ·m",
      "scope": "material",
      "conditions": {
        "temperature": "room temperature (printed as r.t.)",
        "form": "alpha, polycrystalline"
      },
      "method": "Value printed in the Wikipedia infobox",
      "status": "ground",
      "source": "wikipedia-la",
      "where": "Infobox, row Electrical resistivity, alpha poly 615 nΩ⋅m (at r.t.)",
      "source_detail": {
        "title": "Lanthanum (Wikipedia)",
        "url": "https://en.wikipedia.org/wiki/Lanthanum",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA 4.0 (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Air at room temperature",
      "headline": "Lanthanum tarnishes quite rapidly in air and turns completely dark within several hours.",
      "effect": "Wikipedia says lanthanum tarnishes quite rapidly in air, turning completely dark after several hours. The Ames and ESPI sheets list exposure to moist air or water as a condition to avoid, and say the metal should be kept under argon.",
      "rating": "severe",
      "conditions": {
        "atmosphere": "air",
        "temperature": "room temperature"
      },
      "source": "wikipedia-la",
      "where": "Characteristics, Chemical; the sentence on air reactivity"
    },
    {
      "environment": "Water",
      "headline": "Lanthanum reacts slowly with water to form lanthanum hydroxide, and releases hydrogen when water is present in a fire.",
      "effect": "Wikipedia says the metal reacts slowly with water to form lanthanum(III) hydroxide. The ESPI SDS says it may react with water under fire conditions and release flammable hydrogen gas, and the Lesker MSDS says it can react with water to form explosive H2.",
      "rating": "severe",
      "conditions": {
        "temperature": "not stated for the slow reaction; hydrogen release is stated under fire conditions"
      },
      "source": "espi-la-sds",
      "where": "Section 5 Specific Hazards; Section 10 Possibility of Hazardous Reactions; Lesker MSDS Section VII"
    },
    {
      "environment": "Dilute and strong acids",
      "headline": "Lanthanum reacts vigorously with acids and releases flammable hydrogen.",
      "effect": "The ESPI SDS says the metal reacts vigorously with acids, releasing flammable hydrogen gas, and lists strong acids and acid chlorides as incompatible. The Lesker MSDS also lists strong acids as incompatible.",
      "rating": "severe",
      "conditions": {
        "acid": "strong acids, concentration not stated",
        "temperature": "not stated"
      },
      "source": "espi-la-sds",
      "where": "Section 10, Possibility of Hazardous Reactions and Incompatible Materials"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem GHS summary: 146 of 248 company reports (58.9 %) say the substance does not meet GHS criteria. Among the notified classifications, H228 flammable solid appears in 23.4 % and H260 (in contact with water releases flammable gases which may ignite spontaneously) in 19 %, with signal word Danger.",
        "ghs": [
          "H228",
          "H260"
        ],
        "source": "pubchem-la",
        "where": "Safety and Hazards, Hazards Identification, GHS Classification"
      },
      {
        "text": "ESPI Metals SDS for lanthanum solid: GHS classification flammable solids, category 2, with hazard statement H228 and signal word Warning. Section 15 of the same SDS gives CLP as flammable solids, category 1, so the two sections disagree.",
        "ghs": [
          "H228"
        ],
        "source": "espi-la-sds",
        "where": "Section 2 Hazards Identification; Section 15 Regulatory Information"
      },
      {
        "text": "Kurt J. Lesker MSDS (1991) lists the metal as a DOT flammable solid. It says that lanthanum and lanthanons can cause delayed blood clotting leading to hemorrhages, and has caused liver injury in experimental animals. The same sheet says no toxicity data are available.",
        "ghs": [],
        "source": "lesker-la-msds",
        "where": "Section IV Fire and Explosion Hazard Data; Section VI Health Hazard Data"
      },
      {
        "text": "PubChem's hazards summary gives low to moderate acute toxicity, and lists lanthanum as fibrogenic (causing tissue injury and fibrosis).",
        "ghs": [],
        "source": "pubchem-la",
        "where": "Safety and Hazards, Hazards Summary; Toxicity, Adverse Effects"
      },
      {
        "text": "ESPI SDS transport entry: UN3178, flammable solid, inorganic, n.o.s. (Lanthanum), class 4.1, packing group II.",
        "ghs": [],
        "source": "espi-la-sds",
        "where": "Section 14 Transport Information"
      },
      {
        "text": "Exposure limits differ by sheet. The Lesker MSDS lists a TLV of 10 mg/m3 and an OSHA PEL of 15 mg/m3. The ESPI and Ames SDSs both state that no OSHA PEL or ACGIH TLV has been established.",
        "ghs": [],
        "source": "lesker-la-msds",
        "where": "Section II Hazardous Ingredients, TLV and OSHA PEL columns; ESPI SDS Section 8 Exposure Limits"
      }
    ],
    "failure_risks": [
      {
        "mode": "Fire in chips, pieces, powder and dust",
        "trigger": "Lanthanum pieces, powder or dust exposed to heat, sparks or flame, or dust raised during grinding or melting",
        "consequence": "The metal is a flammable solid (H228) and will burn under fire conditions. The Lesker MSDS lists a dust explosion hazard, and the Ames SDS says grinding, melting or welding can produce hazardous dust or fumes.",
        "severity": "high",
        "source": "espi-la-sds",
        "where": "Section 5 Firefighting Measures; Section 10 Possibility of Hazardous Reactions; Lesker MSDS Section IV Unusual Fire and Explosion Hazards"
      },
      {
        "mode": "Hydrogen release on contact with water or acid",
        "trigger": "Metal in contact with water (especially under fire conditions) or with strong acids",
        "consequence": "The reaction releases flammable hydrogen. PubChem's notifications record H260 (may ignite spontaneously) in 19 % of reports, and the ESPI SDS says the metal reacts vigorously with acids.",
        "severity": "high",
        "source": "pubchem-la",
        "where": "Safety and Hazards, GHS Classification (H260 19 %); ESPI SDS Section 10"
      },
      {
        "mode": "Tarnishing and loss of surface in air",
        "trigger": "Exposure to air, and especially moist air",
        "consequence": "The surface darkens within hours. The Ames and ESPI sheets say the metal must be kept under argon, or under mineral oil in the Ames case, to avoid this.",
        "severity": "moderate",
        "source": "wikipedia-la",
        "where": "Characteristics, Chemical, air reactivity; Ames SDS Section 7 Conditions for Safe Storage"
      },
      {
        "mode": "Reaction with halogens and strong oxidizers",
        "trigger": "Contact with halogens, strong oxidizers, sulfur or phosphorus",
        "consequence": "The Lesker MSDS lists these as materials to avoid. The sheet does not give a reaction rate or temperature, so the severity is an assessment from the listing alone.",
        "severity": "moderate",
        "source": "lesker-la-msds",
        "where": "Section VII Reactivity Data, Incompatibility"
      }
    ],
    "side_effects": [
      {
        "text": "PubChem reports that a printer and a movie projectionist exposed to rare-earth metals in the dust of carbon arc lamps retained lanthanum in their lungs.",
        "affects": "Workers exposed to lanthanum dust or fume",
        "source": "pubchem-la",
        "where": "Safety and Hazards, Hazards Summary"
      }
    ],
    "handling": [
      {
        "text": "Handle under dry argon in an enclosed, controlled process, and use local exhaust to keep dust below exposure limits (ESPI SDS). Do not blow dust off clothing or skin with compressed air.",
        "source": "espi-la-sds",
        "where": "Section 7 Handling and Storage; Section 8 Engineering Controls"
      },
      {
        "text": "Store in tightly sealed containers under argon, protect from water and moisture, and keep away from acids and oxidizers. The Ames SDS also allows mineral oil.",
        "source": "ames-la-sds",
        "where": "Section 7 Conditions for Safe Storage"
      },
      {
        "text": "Fire: use a Class D dry powder extinguisher and do not use water (ESPI SDS). The Lesker MSDS gives dry chemical and says do not use water, and firefighters should wear self-contained breathing apparatus.",
        "source": "lesker-la-msds",
        "where": "Section IV Extinguishing Media and Special Fire Fighting Procedures"
      },
      {
        "text": "Spill: avoid raising dust, use non-sparking tools, sweep or scoop the material into a closed container, and do not use water for cleanup (ESPI SDS).",
        "source": "espi-la-sds",
        "where": "Section 6 Accidental Release Measures"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "optics-and-cameras",
      "device": "Lanthanum oxide in high-index optical glass for camera and telescope lenses (ground-manufactured)",
      "example": "Wikipedia says lanthanum(III) oxide is used in optical glass, including camera and telescope lenses, because of its high refractive index. PubChem lists the same use for special optical glasses such as infrared-absorbing glass.",
      "source": "wikipedia-la",
      "where": "Applications section, lanthanum(III) oxide paragraph; PubChem Use and Manufacturing, Uses"
    },
    {
      "application": "propulsion-and-tanks",
      "device": "Lanthanum hexaboride (LaB6) thermionic emitter in a hollow cathode for Hall thrusters (a compound, not the metal; design record, no flight reported)",
      "example": "A NASA Tech Briefs record (2010) describes a compact hollow cathode with a LaB6 thermionic emitter that gives 10 to 60 A of emission and whose keeper diameter lets it sit on the centerline of a 6-kW Hall thruster. It says LaB6 needs less stringent xenon purity than barium oxide cathodes.",
      "source": "ntrs-hollow-cathode-2010",
      "where": "Abstract excerpts, \"Compact Rare Earth Emitter Hollow Cathode\", NASA Tech Briefs, March 2010"
    },
    {
      "application": "batteries",
      "device": "Lanthanum-containing alloy anode in nickel-metal hydride (NiMH) rechargeable batteries (an alloy, not the metal)",
      "example": "PubChem lists lanthanum as used in nickel-metal-hydride rechargeable batteries. Wikipedia says a lanthanum-containing alloy is one material used for the anode of nickel-metal hydride batteries.",
      "source": "wikipedia-la",
      "where": "Applications section, battery paragraph; PubChem Use and Manufacturing, Uses"
    }
  ],
  "supply": [
    {
      "subject": "Rare earths (lanthanum is not reported separately by USGS)",
      "abundance": "39 mg/kg of the Earth's crust (Wikipedia, which cites a crust figure)",
      "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": [],
      "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-ree-2026",
      "where": "World Mine Production table, 2025 (world total 390,000 t, rounded; shares calculated by Space Mushroom from China 270,000, United States 51,000, Australia 29,000 and Burma 22,000). Recycling and Substitutes sections. Abundance: Wikipedia Occurrence section."
    },
    {
      "subject": "Lanthanum oxide price and China export controls",
      "producers": [],
      "critical_lists": [],
      "recycling": "",
      "substitutes": [],
      "source": "usgs-ree-2026",
      "where": "Salient Statistics, price row Lanthanum oxide, 99.5% minimum, 1.00 dollars per kg in 2025e (0.97 in 2024). Events, Trends, and Issues: the April 2025 Chinese export controls name samarium, gadolinium, terbium, dysprosium, lutetium, scandium and yttrium, and do not name lanthanum."
    },
    {
      "subject": "Rare-earth compounds and metals imported into the United States",
      "producers": [
        {
          "country": "China",
          "share_percent": 71,
          "year": 2024
        },
        {
          "country": "Malaysia",
          "share_percent": 13,
          "year": 2024
        },
        {
          "country": "Japan",
          "share_percent": 5,
          "year": 2024
        },
        {
          "country": "Estonia",
          "share_percent": 5,
          "year": 2024
        }
      ],
      "critical_lists": [],
      "recycling": "",
      "substitutes": [],
      "source": "usgs-ree-2026",
      "where": "Import Sources (2021 to 2024) paragraph: China 71 %, Malaysia 13 %, Japan 5 %, Estonia 5 %. The year column shows the end of the 2021 to 2024 range. This covers all rare-earth compounds and metals, not lanthanum alone."
    }
  ],
  "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: Lanthanum",
      "type": "database",
      "url": "https://en.wikipedia.org/wiki/Lanthanum",
      "year": 2026
    },
    {
      "title": "PubChem compound record for lanthanum (CID 23926), including ECHA C&L Inventory classification",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/23926",
      "year": 2026
    },
    {
      "title": "WebElements: Lanthanum, physical properties (University of Sheffield)",
      "type": "datasheet",
      "url": "https://winter.group.shef.ac.uk/webelements/lanthanum/physics.html"
    },
    {
      "title": "Safety data sheet: Lanthanum solid (ESPI Metals), copy on the supplier site",
      "type": "sds",
      "url": "https://www.espimetals.com/index.php/msds/500-lanthanum-msds"
    },
    {
      "title": "Kurt J. Lesker Company material safety data sheet: Lanthanum metal (revised 6/25/91)",
      "type": "sds",
      "url": "https://www.lesker.com/newweb/deposition_materials/pdf/msds_la.pdf",
      "year": 1991
    },
    {
      "title": "Safety data sheet: Lanthanum, Ames Laboratory 57 Lanthanum SDS (revised January 26, 2016)",
      "type": "sds",
      "url": "https://www.external.ameslab.gov/sites/default/files/inline-files/57_Lanthanum_SDS.pdf",
      "year": 2016
    },
    {
      "title": "Compact Rare Earth Emitter Hollow Cathode (NASA Tech Briefs, March 2010; NTRS 20100009696)",
      "type": "paper",
      "url": "https://ntrs.nasa.gov/citations/20100009696",
      "year": 2010
    }
  ],
  "gaps": [
    "Lanthanum-specific production: USGS reports rare earths as one group, so the producer shares above are for all rare earths, not for lanthanum. No year-stamped world output for lanthanum metal alone was found in an opened source.",
    "Critical-mineral listing: the USGS 2025 critical minerals list and the EU critical raw materials list were not opened for lanthanum, so critical_lists is empty.",
    "Space flight of lanthanum metal: no flight use of the metal was found. The only space-related source is the 2010 NASA Tech Briefs record for a LaB6 compound cathode, which reports a design and no flight.",
    "Mechanical strength: no tensile, yield or annealed strength for lanthanum metal was found in an opened source. The Goodfellow lanthanum product page returned HTTP 404 and was not read.",
    "Hardness: brinell_hardness and vickers_hardness are new names, because the property file has no canonical name for hardness. WebElements prints Brinell and Vickers in MN m-2, and Wikipedia gives a Brinell range.",
    "Melting point and density differ between sources (918 to 921 °C; 6.145 to 6.17 g/cc at 20 to 25 °C). All values are entered with their own source and conditions, and none has been averaged.",
    "Boiling point: the Lesker sheet prints 3457 °C with a label that is not clear, so it is not entered. Wikipedia and PubChem both give 3464 °C.",
    "Hazard classification: the ESPI and Ames SDSs give flammable solid category 2 in Section 2 but category 1 in Section 15, and the 1991 Lesker sheet has no GHS statements. The PubChem notifications differ from the SDSs, and 58.9 % of its reports do not meet GHS criteria.",
    "Exposure limits: the Lesker sheet gives a TLV of 10 mg/m3 and an OSHA PEL of 15 mg/m3, while the ESPI and Ames sheets say no limit is established. Both are reported and neither is used as a limit.",
    "Corrosion data are qualitative (Wikipedia, PubChem and the SDS sheets). No measured weight-gain or corrosion-rate figure for lanthanum in air or water was found.",
    "Superconducting transition temperature: the Wikipedia page as read did not include a value in its infobox text, so none is entered.",
    "The PubChem web page returned a browser check, so the record was read through PubChem's public REST view (pug_view) for CID 23926.",
    "The American Elements, Stanford Advanced Materials and Sigma-Aldrich lanthanum SDSs were found in search results but not opened, and the Angstrom Sciences SDS was downloaded but not read in full.",
    "Battery use: no open-access review of lanthanum in NiMH alloys was found. The battery use is supported only by the Wikipedia and PubChem statements, and it describes an alloy, not the metal."
  ],
  "story": {
    "why": "Lanthanum is a silvery rare-earth metal with a density of 6.145 g/cm3 at 20 °C and a melting point of 920 °C (Wikipedia). It is used mainly as lanthanum oxide in high-index optical glass, as an alloy component in nickel-metal-hydride battery anodes, and in catalysts. Its space-related interest is narrower: a NASA design record from 2010 describes lanthanum hexaboride, a compound, as the emitter in a Hall-thruster hollow cathode. No flight of the metal was found.",
    "uses": [
      {
        "where": "Optical glass",
        "line": "Wikipedia says lanthanum(III) oxide is used in optical glass, including camera and telescope lenses, because of its high refractive index. PubChem lists the same optical uses."
      },
      {
        "where": "Hall-thruster cathode emitter (design record)",
        "line": "A NASA Tech Briefs record from March 2010 describes a compact hollow cathode with a LaB6 thermionic emitter that gives 10 to 60 A of emission and fits on the centerline of a 6-kW Hall thruster. It is a design record, and no flight is reported in it."
      },
      {
        "where": "Nickel-metal-hydride batteries",
        "line": "A lanthanum-containing alloy is one anode material in nickel-metal-hydride batteries (Wikipedia), and PubChem lists the same battery use."
      }
    ],
    "can_do": [
      {
        "label": "Weight",
        "line": "Density is 6.145 g/cm3 at 20 °C (Wikipedia). PubChem gives 6.166 at 25 °C, and the ESPI SDS gives 6.17 at 20 °C.",
        "benchmark": "density",
        "scope": "material",
        "value": "6.145 g/cm3"
      },
      {
        "label": "Melting",
        "line": "Melting point is 920 °C (Wikipedia and PubChem). The ESPI SDS gives 918 °C, and the Lesker sheet gives 921 °C.",
        "benchmark": "melting_point",
        "scope": "material",
        "value": "920 °C"
      },
      {
        "label": "Heat conduction",
        "line": "Thermal conductivity is 13.4 W/(m·K) in the Wikipedia infobox, and WebElements gives 13 W/(m·K).",
        "benchmark": "thermal_conductivity",
        "scope": "material",
        "value": "13.4 W/(m·K)"
      },
      {
        "label": "Stiffness",
        "line": "Young's modulus of the alpha form is 36.6 GPa (Wikipedia). WebElements gives 37 GPa.",
        "benchmark": "elastic_modulus",
        "scope": "material",
        "value": "36.6 GPa"
      }
    ],
    "compare": "Lanthanum is a dense, soft rare-earth metal, at 6.145 g/cm3 with a melting point of 920 °C. Its thermal conductivity of 13.4 W/(m·K) is modest for a metal, and its Young's modulus of about 37 GPa is low for a structural metal. Its value to designers is chemical: it is a flammable solid that tarnishes in air and releases hydrogen with water and acids, so it is used as an oxide in glass, not as a structural part. No comparison profile is carried in this file, so the rows below list lanthanum values only.",
    "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": [
      "Handle under dry argon in an enclosed process with local exhaust (ESPI).",
      "Store in sealed containers under argon, away from moisture, acids and oxidizers (ESPI, Ames).",
      "Do not use water on a fire. Use a Class D dry powder extinguisher (ESPI, Lesker).",
      "Sweep spills into a closed container with non-sparking tools, and do not use water for cleanup (ESPI)."
    ],
    "good_for": [
      "Optical glass: lanthanum oxide raises the refractive index, which is why it is used in camera and telescope lenses (Wikipedia).",
      "Electric-propulsion cathodes: the LaB6 emitter design gives 10 to 60 A in a compact hollow cathode (NASA Tech Briefs, 2010). This is a compound.",
      "Battery alloys: lanthanum-containing alloys are used as anodes in nickel-metal-hydride batteries (Wikipedia)."
    ],
    "watch_out": [
      "Flammable solid with a dust explosion hazard (ESPI, Lesker, Ames).",
      "Water and strong acids release hydrogen, and the metal tarnishes in air within hours (ESPI, Wikipedia).",
      "Supply is concentrated: China produced about 69 % of world rare-earth mine output in 2025, a group figure (USGS). Lanthanum oxide was not named in China's April 2025 export controls (USGS).",
      "The SDSs disagree on GHS category and exposure limits, and most toxicology data are missing."
    ],
    "verdict": "Lanthanum is a dense rare-earth metal, at 6.145 g/cm3 with a melting point of 920 °C, whose practical value is as an oxide in optical glass and as a battery-alloy component. The metal itself is a flammable solid that tarnishes in air and reacts with water and acids, so it needs dry, argon-sealed handling. Its space link is a LaB6 compound cathode design from 2010, not a flown part of the metal.",
    "recipe": {
      "line": "Lanthanum is a single-element metal (La). Wikipedia says it is obtained by heating its oxide with ammonium chloride or fluoride, followed by reduction with an alkali or alkaline-earth metal in vacuum or argon. It can also be made by electrolysis of a molten mixture of anhydrous chlorides. It is mined with the other rare earths.",
      "parts": [
        {
          "name": "Lanthanum",
          "symbol": "La",
          "role": "The whole material. The Lesker and ESPI sheets list 100 % lanthanum, and PubChem gives a molecular weight of 138.9055 for the element.",
          "atoms": 1,
          "atomic_weight": 138.9055
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "Lanthanum metal is classed as a flammable solid. Toxicity data are thin, and the sources disagree on exposure limits.",
        "points": [
          {
            "label": "Chips, powder and dust",
            "line": "The ESPI and Ames SDSs classify the metal as a flammable solid (H228), and the Lesker sheet lists a dust explosion hazard."
          },
          {
            "label": "Water and acids",
            "line": "Contact with water or strong acids releases hydrogen. PubChem records H260 (may ignite spontaneously) in 19 % of its notifications."
          },
          {
            "label": "Dust limits",
            "line": "The Lesker sheet gives a TLV of 10 mg/m3 and an OSHA PEL of 15 mg/m3. The ESPI and Ames sheets say no limit is established."
          },
          {
            "label": "Toxicity",
            "line": "PubChem gives low to moderate acute toxicity and calls lanthanum fibrogenic. The Lesker sheet mentions delayed blood clotting and liver injury in animals, and says no toxicity data are available."
          }
        ],
        "level": 1,
        "verdict": "Form-dependent"
      },
      {
        "title": "If it fails",
        "lead": "The sources give three failure routes: a fire in fine metal or dust, hydrogen release with water or acid, and tarnishing in moist air.",
        "points": [
          {
            "label": "Fire",
            "line": "Use a Class D dry powder agent and do not use water on the burning metal (ESPI, Lesker)."
          },
          {
            "label": "Hydrogen",
            "line": "Water or strong acid releases flammable hydrogen (ESPI, PubChem)."
          },
          {
            "label": "Tarnish",
            "line": "The surface turns dark in air within hours, so it is kept under argon (Wikipedia, ESPI)."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Keep it dry",
            "line": "Store in sealed containers under argon, protect from moisture, and keep away from acids and oxidizers (ESPI, Ames)."
          },
          {
            "label": "Dust control",
            "line": "Handle in an enclosed process with local exhaust, and do not blow dust off clothing or skin with compressed air (ESPI)."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 26,
    "unreachable": 2,
    "caveats": 6,
    "note": "Read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable: Goodfellow lanthanum metal page (HTTP 404); PubChem web page (browser check, read through the REST view instead). Caveats: most physical values come from Wikipedia and one WebElements page; supply shares are for all rare earths, not lanthanum; the boiling point and exposure limits differ between sources; the hazard classes differ between sections and dates; the LaB6 cathode is a compound design record."
  },
  "sources": {
    "usgs-ree-2026": {
      "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-la": {
      "title": "Lanthanum (Wikipedia)",
      "url": "https://en.wikipedia.org/wiki/Lanthanum",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA 4.0 (cited, not reproduced)"
    },
    "pubchem-la": {
      "title": "PubChem compound record: Lanthanum (CID 23926), including ECHA C&L Inventory classification",
      "id": "CAS 7439-91-0",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23926/JSON",
      "year": 2026,
      "kind": "database",
      "license": "PubChem (NCBI), public domain; sections attributed to ECHA and others"
    },
    "webelements-la": {
      "title": "WebElements: Lanthanum, physical properties (University of Sheffield)",
      "url": "https://winter.group.shef.ac.uk/webelements/lanthanum/physics.html",
      "kind": "database",
      "license": "WebElements, cited not reproduced"
    },
    "espi-la-sds": {
      "title": "Safety data sheet: Lanthanum solid (ESPI Metals)",
      "id": "CAS 7439-91-0; EC 231-099-0",
      "url": "https://www.espimetals.com/index.php/msds/500-lanthanum-msds",
      "kind": "datasheet",
      "license": "supplier safety data sheet, cited not reproduced"
    },
    "lesker-la-msds": {
      "title": "Kurt J. Lesker Company material safety data sheet: Lanthanum metal (6/25/91)",
      "id": "CAS 7439-91-0",
      "url": "https://www.lesker.com/newweb/deposition_materials/pdf/msds_la.pdf",
      "year": 1991,
      "kind": "datasheet",
      "license": "supplier safety data sheet, cited not reproduced"
    },
    "ames-la-sds": {
      "title": "Safety data sheet: Lanthanum, Ames Laboratory 57 Lanthanum SDS (revised January 26, 2016)",
      "url": "https://www.external.ameslab.gov/sites/default/files/inline-files/57_Lanthanum_SDS.pdf",
      "year": 2016,
      "kind": "datasheet",
      "license": "laboratory safety data sheet, cited not reproduced"
    },
    "ntrs-hollow-cathode-2010": {
      "title": "Compact Rare Earth Emitter Hollow Cathode (Watkins, Goebel, Hofer; NASA Tech Briefs, March 2010)",
      "id": "NTRS 20100009696",
      "url": "https://ntrs.nasa.gov/citations/20100009696",
      "year": 2010,
      "kind": "paper",
      "license": "NASA public record, cited not reproduced"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/lanthanum/"
}