{
  "spore": "profile",
  "id": "samarium-oxide",
  "spore_version": "0.2",
  "family": "oxide-ceramics",
  "name": "Samarium(III) oxide",
  "abbreviation": "Sm2O3",
  "role": "neutron-absorber and optical-glass oxide, and a high-k dielectric studied for MOS devices",
  "category": "ceramics",
  "type": "oxides",
  "summary": "Samarium(III) oxide (Sm2O3, CAS 12060-58-1) is a solid with a cubic crystal structure and a molecular weight of 348.7 g/mol per PubChem. PubChem gives a density of 8.347 g/cm3 at 25 °C. A Nanografi product page gives 8.43 g/cm3, and the melting point is printed as 2325 °C in a Thermo Fisher safety data sheet and as 2335 °C on the Nanografi page. Suppliers list the oxide for neutron absorbers in reactor control rods and for optical and infrared-absorbing glasses. An open-access 2019 modelling paper quotes a dielectric constant of up to 15 for amorphous films. No space flight, vacuum or radiation test on Sm2O3 was found in the sources read.\n",
  "best_for": "Dense rare-earth oxide for optical and infrared-absorbing glass and for neutron-absorber uses, as listed by suppliers",
  "weakest_at": "No space or radiation test data for Sm2O3, and melting-point and density values that differ between suppliers and PubChem",
  "identity": {
    "formula": "Sm2O3",
    "cas": "12060-58-1",
    "crystal_system": "cubic",
    "designations": [],
    "source": "saip-sm2o3-poster",
    "where": "Abstract (XRD confirms a cubic structure). CAS 12060-58-1 and molecular formula O3Sm2 from PubChem CID 159425, Names and Identifiers"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "radiation-shielding",
      "optics-and-cameras",
      "electronics-and-chips"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "value": 8.347,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C",
        "form": "Sm2O3 powder"
      },
      "method": "Database value, read from the PubChem record for CID 159425",
      "status": "ground",
      "source": "pubchem-sm2o3",
      "where": "Chemical and Physical Properties, Experimental Properties, Density",
      "source_detail": {
        "title": "PubChem compound record, Samarium(III) oxide (CID 159425): Experimental Properties, Computed Properties, GHS Classification, Physical Description",
        "id": "CID 159425; CAS 12060-58-1",
        "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/159425/JSON",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    },
    {
      "benchmark": "density",
      "value": 8.43,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "Sm2O3 powder (micron powder product, 325 mesh, supplier listing)"
      },
      "method": "Value printed on a supplier product page (not a test method stated)",
      "status": "ground",
      "note": "Supplier value. It differs from the PubChem value of 8.347 g/cm3 and from the 8.347 printed in the Thermo Fisher SDS.",
      "source": "nanografi-sm2o3-powder",
      "where": "Product specification block, density field",
      "source_detail": {
        "title": "Nanografi: Samarium oxide (Sm2O3) powder product page",
        "id": "supplier product page",
        "url": "https://shop.nanografi.com/rare-earth-materials/rare-earth-oxide-powder/samarium-oxide-sm2o3-powder/",
        "year": 2026,
        "kind": "web",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "value": 2325,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "purity": "99.9 weight percent Sm2O3 (Thermo Fisher Cat. No. 36278)"
      },
      "method": "Value printed in a supplier safety data sheet, Section 9",
      "status": "ground",
      "note": "The PubChem record gives no melting point for Sm2O3, so this value comes from the supplier SDS.",
      "source": "wsu-sm2o3-sds",
      "where": "Section 9, Physical and chemical properties, Melting Point/Range row",
      "source_detail": {
        "title": "Thermo Fisher Scientific safety data sheet, Samarium(III) oxide, Cat. No. 36278, revision 29 March 2024 (hosted by Washington State University)",
        "id": "Cat. No. 36278; CAS 12060-58-1",
        "url": "https://wpcdn.web.wsu.edu/wp-research/uploads/sites/2909/2025/05/Samarium-III-Oxide-12060-58-1.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "supplier safety data sheet, linked not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "value": 2335,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "nanopowder and powder listings on the supplier page"
      },
      "method": "Value printed on a supplier product page",
      "status": "ground",
      "note": "Supplier value. It is 10 °C above the 2325 °C printed in the Thermo Fisher SDS.",
      "source": "nanografi-sm2o3-powder",
      "where": "Product specification block, melting point field",
      "source_detail": {
        "title": "Nanografi: Samarium oxide (Sm2O3) powder product page",
        "id": "supplier product page",
        "url": "https://shop.nanografi.com/rare-earth-materials/rare-earth-oxide-powder/samarium-oxide-sm2o3-powder/",
        "year": 2026,
        "kind": "web",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "boiling_point",
      "value": 4118,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "samarium oxide nanopowder listing"
      },
      "method": "Value printed on a supplier product page, in the same sentence as the 2335 °C melting point",
      "status": "ground",
      "note": "Supplier value for a nanopowder listing, not a PubChem or SDS value.",
      "source": "nanografi-sm2o3-nano",
      "where": "Product description, melting and boiling points sentence",
      "source_detail": {
        "title": "Nanografi: Samarium oxide nanoparticles product page",
        "id": "supplier product page",
        "url": "https://shop.nanografi.com/nanoparticles/single-metal-oxide-nanoparticles/samarium-oxide-nanoparticles/",
        "year": 2026,
        "kind": "web",
        "license": "supplier web page, linked not reproduced"
      }
    },
    {
      "benchmark": "molecular_weight",
      "value": 348.7,
      "bound": "exact",
      "unit": "g/mol",
      "scope": "material",
      "conditions": {
        "basis": "computed by PubChem from the molecular formula"
      },
      "method": "Computed property read from the PubChem record for CID 159425",
      "status": "calculated",
      "source": "pubchem-sm2o3",
      "where": "Computed Properties, Molecular Weight",
      "source_detail": {
        "title": "PubChem compound record, Samarium(III) oxide (CID 159425): Experimental Properties, Computed Properties, GHS Classification, Physical Description",
        "id": "CID 159425; CAS 12060-58-1",
        "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/159425/JSON",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    },
    {
      "benchmark": "lattice_parameter",
      "label": "Lattice parameter a, cubic Sm2O3 (conference abstract)",
      "value": 10.94,
      "bound": "exact",
      "unit": "Å",
      "scope": "material",
      "conditions": {
        "crystal_system": "cubic",
        "temperature": "sample calcined at 500 and 700 °C (the abstract does not say which calcination temperature gives this lattice parameter)"
      },
      "method": "X-ray diffraction, as reported in the abstract of a 2025 conference contribution",
      "status": "ground",
      "note": "From a conference abstract, not a peer-reviewed paper.",
      "source": "saip-sm2o3-poster",
      "where": "Abstract, sentence beginning \"The structural analysis through x-ray diffraction\"",
      "source_detail": {
        "title": "Effect of Temperature on Structural and Optical Properties of Sm2O3 (SAIP 2025 conference contribution)",
        "id": "SAIP 2025, contribution 463",
        "url": "https://events2.saip.org.za/event/1/contributions/463/contribution.pdf",
        "year": 2025,
        "kind": "paper",
        "license": "conference abstract, linked not reproduced"
      }
    },
    {
      "benchmark": "band_gap",
      "label": "Measured band gap, cubic Sm2O3 crystal",
      "value": 4.9,
      "bound": "exact",
      "unit": "eV",
      "scope": "material",
      "conditions": {
        "crystal_system": "cubic",
        "basis": "value quoted by the 2019 paper from earlier measurements (its references 41 and 42)"
      },
      "method": "Measured value quoted in Section 3.1.3 of the modelling paper",
      "status": "ground",
      "note": "Quoted value, not measured by the authors of the 2019 paper. The paper gives 4.7 eV for monoclinic and 5.1 eV for hexagonal Sm2O3 for comparison.",
      "source": "olsson-cai-2019",
      "where": "Section 3.1.3 Electronic Properties, first sentence on measured band gaps",
      "source_detail": {
        "title": "Structural, Elastic, Vibrational and Electronic Properties of Amorphous Sm2O3 from Ab Initio Calculations (Olsson, Cai, Cottom, Jakobsen, Shluger)",
        "id": "doi:10.1016/j.commatsci.2019.109119 (Computational Materials Science, 2019); UCL Discovery eprint 10084314",
        "url": "https://discovery.ucl.ac.uk/id/eprint/10084314/1/Revised%20Manuscript.pdf",
        "year": 2019,
        "kind": "paper",
        "license": "open access via UCL Discovery (as listed)"
      }
    },
    {
      "benchmark": "dielectric_constant",
      "label": "Dielectric constant of amorphous Sm2O3 films, upper value quoted",
      "value": 15,
      "bound": "upper",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "phase": "amorphous films",
        "basis": "value quoted by the paper from three earlier film studies (its references 27 to 29)"
      },
      "method": "Literature value quoted in the Introduction of the modelling paper",
      "status": "ground",
      "note": "A quoted upper value for thin amorphous films. Film thickness and deposition method are not given in the text read.",
      "source": "olsson-cai-2019",
      "where": "Introduction, paragraph on high-k dielectric use (text \"up to 15 for the amorphous films\")",
      "source_detail": {
        "title": "Structural, Elastic, Vibrational and Electronic Properties of Amorphous Sm2O3 from Ab Initio Calculations (Olsson, Cai, Cottom, Jakobsen, Shluger)",
        "id": "doi:10.1016/j.commatsci.2019.109119 (Computational Materials Science, 2019); UCL Discovery eprint 10084314",
        "url": "https://discovery.ucl.ac.uk/id/eprint/10084314/1/Revised%20Manuscript.pdf",
        "year": 2019,
        "kind": "paper",
        "license": "open access via UCL Discovery (as listed)"
      }
    },
    {
      "benchmark": "bulk_modulus",
      "label": "Bulk modulus, cubic Sm2O3, experimental range quoted",
      "value": 130,
      "value_high": 149,
      "bound": "range",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "crystal_system": "cubic",
        "basis": "experimental range quoted by the paper from its references 40, 35 and 90"
      },
      "method": "Experimental values quoted in Table 3 of the modelling paper",
      "status": "ground",
      "source": "olsson-cai-2019",
      "where": "Table 3, Experimental row, Bulk modulus column",
      "source_detail": {
        "title": "Structural, Elastic, Vibrational and Electronic Properties of Amorphous Sm2O3 from Ab Initio Calculations (Olsson, Cai, Cottom, Jakobsen, Shluger)",
        "id": "doi:10.1016/j.commatsci.2019.109119 (Computational Materials Science, 2019); UCL Discovery eprint 10084314",
        "url": "https://discovery.ucl.ac.uk/id/eprint/10084314/1/Revised%20Manuscript.pdf",
        "year": 2019,
        "kind": "paper",
        "license": "open access via UCL Discovery (as listed)"
      }
    },
    {
      "benchmark": "bulk_modulus",
      "label": "Bulk modulus, cubic Sm2O3, calculated",
      "value": 137.26,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "crystal_system": "cubic",
        "basis": "ab initio calculation in the modelling paper, with an interatomic potential"
      },
      "method": "Calculated value from the modelling paper",
      "status": "calculated",
      "source": "olsson-cai-2019",
      "where": "Table 3, Cubic row, B (GPa) column",
      "source_detail": {
        "title": "Structural, Elastic, Vibrational and Electronic Properties of Amorphous Sm2O3 from Ab Initio Calculations (Olsson, Cai, Cottom, Jakobsen, Shluger)",
        "id": "doi:10.1016/j.commatsci.2019.109119 (Computational Materials Science, 2019); UCL Discovery eprint 10084314",
        "url": "https://discovery.ucl.ac.uk/id/eprint/10084314/1/Revised%20Manuscript.pdf",
        "year": 2019,
        "kind": "paper",
        "license": "open access via UCL Discovery (as listed)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Young's modulus, cubic Sm2O3, calculated",
      "value": 191.06,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "crystal_system": "cubic",
        "basis": "calculated value in the modelling paper"
      },
      "method": "Calculated value from the modelling paper",
      "status": "calculated",
      "source": "olsson-cai-2019",
      "where": "Table 3, Cubic row, E (GPa) column",
      "source_detail": {
        "title": "Structural, Elastic, Vibrational and Electronic Properties of Amorphous Sm2O3 from Ab Initio Calculations (Olsson, Cai, Cottom, Jakobsen, Shluger)",
        "id": "doi:10.1016/j.commatsci.2019.109119 (Computational Materials Science, 2019); UCL Discovery eprint 10084314",
        "url": "https://discovery.ucl.ac.uk/id/eprint/10084314/1/Revised%20Manuscript.pdf",
        "year": 2019,
        "kind": "paper",
        "license": "open access via UCL Discovery (as listed)"
      }
    },
    {
      "benchmark": "ld50_oral",
      "label": "Acute oral LD50, Sm2O3, rat",
      "value": 5,
      "bound": "lower",
      "unit": "g/kg",
      "scope": "material",
      "conditions": {
        "species": "rat",
        "route": "oral"
      },
      "method": "Value printed in a supplier safety data sheet, Section 11 (component information)",
      "status": "ground",
      "note": "The SDS prints the value as greater than 5 g/kg, so 5 is a lower bound. No dermal or inhalation figure is listed.",
      "source": "wsu-sm2o3-sds",
      "where": "Section 11, Component Information table, LD50 Oral column",
      "source_detail": {
        "title": "Thermo Fisher Scientific safety data sheet, Samarium(III) oxide, Cat. No. 36278, revision 29 March 2024 (hosted by Washington State University)",
        "id": "Cat. No. 36278; CAS 12060-58-1",
        "url": "https://wpcdn.web.wsu.edu/wp-research/uploads/sites/2909/2025/05/Samarium-III-Oxide-12060-58-1.pdf",
        "year": 2024,
        "kind": "datasheet",
        "license": "supplier safety data sheet, linked not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Moist air and water (storage and handling)",
      "headline": "Sm2O3 is air sensitive and hygroscopic according to the Thermo Fisher SDS.",
      "effect": "The SDS lists exposure to moist air or water as a condition to avoid and says to keep the powder dry in a tightly closed container. It gives no mass-gain figure, so the rate of moisture uptake is not known from this source.",
      "rating": "moderate",
      "conditions": {
        "form": "powder",
        "exposure": "not quantified"
      },
      "source": "wsu-sm2o3-sds",
      "where": "Section 10 (Stability, Conditions to Avoid) and Section 7 (Storage)"
    },
    {
      "environment": "Acids",
      "headline": "Sm2O3 is described as soluble in acids and is listed as incompatible with acids.",
      "effect": "The PubChem record quotes Hawley for insoluble in water and soluble in acids, and the SDS lists acids as incompatible. Neither source gives a dissolution rate or temperature, so the rating is qualitative.",
      "rating": "moderate",
      "conditions": {
        "basis": "qualitative solubility statement",
        "exposure": "not tested in the sources read"
      },
      "source": "pubchem-sm2o3",
      "where": "Experimental Properties, Physical Description (Hawley entry)"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "PubChem's GHS record gives the signal word Warning and lists H400 (very toxic to aquatic life) and H410 (very toxic to aquatic life with long lasting effects), each in 44.6% of company reports.",
        "ghs": [
          "H400",
          "H410"
        ],
        "source": "pubchem-sm2o3",
        "where": "Safety and Hazards, GHS Classification (ECHA C and L notifications summary)"
      },
      {
        "text": "PubChem also notes that this chemical does not meet GHS hazard criteria in 55.4% (129 of 233) of company reports, so the notifications disagree.",
        "ghs": [],
        "source": "pubchem-sm2o3",
        "where": "Safety and Hazards, GHS Classification, Note"
      },
      {
        "text": "The Thermo Fisher SDS says the product is not considered hazardous by the 2012 OSHA Hazard Communication Standard and has no label elements. It prints an oral LD50 greater than 5 g/kg in rat.",
        "ghs": [],
        "source": "wsu-sm2o3-sds",
        "where": "Section 2 (Hazard identification) and Section 11 (Component Information)"
      }
    ],
    "failure_risks": [
      {
        "mode": "Moisture pick-up by the hygroscopic powder",
        "trigger": "Storage or handling in moist air or contact with water",
        "consequence": "The SDS calls the powder air sensitive and hygroscopic and asks for dry, tightly closed storage. The SDS gives no mass-gain figure, so the effect on composition is not quantified.",
        "severity": "moderate",
        "source": "wsu-sm2o3-sds",
        "where": "Section 10 (Stability; Conditions to Avoid)"
      },
      {
        "mode": "Reaction with acids",
        "trigger": "Contact with acids, which the SDS lists as incompatible",
        "consequence": "Sm2O3 is a basic oxide that PubChem describes as soluble in acids, so oxide is lost from a part or powder exposed to acid. No rate or temperature is printed.",
        "severity": "moderate",
        "source": "pubchem-sm2o3",
        "where": "Experimental Properties, Physical Description (Hawley entry); SDS Section 7 incompatible materials"
      }
    ],
    "side_effects": [],
    "handling": [
      {
        "text": "Avoid contact with skin and eyes and do not breathe dust. Handle the product only in a closed system or with appropriate exhaust ventilation.",
        "source": "wsu-sm2o3-sds",
        "where": "Section 7 (Handling)"
      },
      {
        "text": "Keep in a dry, cool, well-ventilated place in a tightly closed container. Keep away from acids, strong oxidizing agents and carbon dioxide.",
        "source": "wsu-sm2o3-sds",
        "where": "Section 7 (Storage; Incompatible Materials)"
      }
    ],
    "mitigations": [
      {
        "text": "Wear chemical safety goggles or eyeglasses and gloves as the SDS directs, and use a particle filter where dust may be breathed.",
        "source": "wsu-sm2o3-sds",
        "where": "Section 8 (Eye/face protection, skin and body protection, respiratory protection)"
      }
    ]
  },
  "uses": [
    {
      "application": "radiation-shielding",
      "device": "Neutron absorber in control rods for nuclear power reactors (supplier listing)",
      "example": "Nanografi lists neutron absorber in control rods for nuclear power reactors among the important application areas of its samarium oxide powder. No test result for this use was read.",
      "source": "nanografi-sm2o3-powder",
      "where": "Product description, Applications list"
    },
    {
      "application": "optics-and-cameras",
      "device": "Optical and infrared-absorbing glasses (supplier listing)",
      "example": "Nanografi lists optical and infrared-absorbing glasses as an important application area of its samarium oxide powder.",
      "source": "nanografi-sm2o3-powder",
      "where": "Product description, Applications list"
    },
    {
      "application": "electronics-and-chips",
      "device": "High-k gate dielectric in MOS devices (research)",
      "example": "The 2019 modelling paper says the most promising electronic device applications for Sm2O3 are found in MOS and ReRAM devices and quotes a dielectric constant of up to 15 for amorphous films.",
      "source": "olsson-cai-2019",
      "where": "Introduction, first paragraphs on electronic device applications"
    }
  ],
  "supply": [
    {
      "subject": "Samarium and rare earths (USGS 2025 mine production, rare-earth oxide equivalent, all rare earths, not samarium alone)",
      "abundance": "Not read in a source opened for this profile.",
      "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 (samarium is listed by name)",
          "listed": true
        }
      ],
      "recycling": "USGS: limited quantities of rare earths were recovered from batteries, permanent magnets and fluorescent lamps. The chapter does not single out samarium oxide.",
      "substitutes": [
        "USGS: substitutes are available for many applications but generally are less effective."
      ],
      "source": "usgs-mcs2026-rare-earths",
      "where": "Salient Statistics (price, net import reliance); World Mine Production and Reserves, 2025 column (world total 390,000 t REO); Events, Trends, and Issues; Recycling; Substitutes. Shares are calculated by Space Mushroom from the printed tonnes and the rounded world total, and cover all rare earths, not samarium alone. Critical list: USGS 2025 List of Critical Minerals page."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "PubChem: Samarium(III) oxide (CID 159425), Experimental Properties, GHS classification, Computed Properties",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/159425/JSON",
      "year": 2026
    },
    {
      "title": "Thermo Fisher Scientific safety data sheet, Samarium(III) oxide, Cat. No. 36278 (revision 29 March 2024), hosted by Washington State University",
      "type": "sds",
      "url": "https://wpcdn.web.wsu.edu/wp-research/uploads/sites/2909/2025/05/Samarium-III-Oxide-12060-58-1.pdf",
      "year": 2024
    },
    {
      "title": "Nanografi: Samarium oxide (Sm2O3) powder product page",
      "type": "datasheet",
      "url": "https://shop.nanografi.com/rare-earth-materials/rare-earth-oxide-powder/samarium-oxide-sm2o3-powder/",
      "year": 2026
    },
    {
      "title": "Nanografi: Samarium oxide nanoparticles product page",
      "type": "datasheet",
      "url": "https://shop.nanografi.com/nanoparticles/single-metal-oxide-nanoparticles/samarium-oxide-nanoparticles/",
      "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": "USGS: About the 2025 List of Critical Minerals",
      "type": "report",
      "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals",
      "year": 2025
    },
    {
      "title": "Effect of Temperature on Structural and Optical Properties of Sm2O3 (SAIP 2025 conference contribution)",
      "type": "paper",
      "url": "https://events2.saip.org.za/event/1/contributions/463/contribution.pdf",
      "year": 2025
    },
    {
      "title": "Olsson, Cai, Cottom, Jakobsen and Shluger: Structural, Elastic, Vibrational and Electronic Properties of Amorphous Sm2O3 from Ab Initio Calculations (Computational Materials Science, 2019; open access via UCL Discovery)",
      "type": "paper",
      "url": "https://discovery.ucl.ac.uk/id/eprint/10084314/1/Revised%20Manuscript.pdf",
      "year": 2019
    }
  ],
  "gaps": [
    "No space flight, vacuum, radiation-test or thermal-vacuum result for Sm2O3 was found in any source read. The neutron-absorber and optical-glass uses are catalogue statements from suppliers.",
    "No PubChem melting point exists for Sm2O3. The two supplier melting points (2325 °C in the SDS and 2335 °C on the Nanografi page) are both kept and not reconciled.",
    "Density differs between PubChem (8.347 g/cm3 at 25 °C), the Nanografi page (8.43 g/cm3) and the Thermo Fisher SDS (specific gravity 8.347, which is the same number). Both values are kept.",
    "Thermal expansion coefficient was not recorded. The 2019 modelling paper prints 8.11 × 10^-6 K^-1 (calculated) and 7.5 − 8.8 × 10^-6 K^-1 (experimental) in exponent form, so per the brief these are left out.",
    "Band gap range across the Sm2O3 phases (4.70 to 5.10 eV in the modelling paper) and thin-film band gaps (3.15 to 4.0 eV) were not recorded as properties. Only the cubic value of 4.9 eV is kept.",
    "The 43 dielectric constant of 1991 electron-beam films was seen only in a search summary and not read in a fetched page, so it is not used. The INIS record for the dielectric film study returned HTTP 402 and the RSC 2023 perspective returned HTTP 403, so neither was read.",
    "Space group of cubic Sm2O3 was not read in a source opened for this profile.",
    "Atomic weights for samarium and oxygen were not read in a source opened for this profile, so the recipe parts carry no atomic_weight. The molecular weight 348.7 g/mol is PubChem's.",
    "Abundance of samarium in the Earth's crust was not read in a source opened for this profile.",
    "The EU critical raw materials list was not checked for samarium.",
    "USGS world production is given for all rare earths. No samarium-only production figure was read, so the producer shares are rare-earth shares.",
    "The PubChem GHS record and the Thermo Fisher SDS disagree on hazard classification (aquatic toxicity warnings versus not hazardous under OSHA). Both are recorded.",
    "Several property names are not in the canonical list (band_gap, lattice_parameter, molecular_weight, ld50_oral). They use short snake_case names as the brief allows."
  ],
  "story": {
    "why": "Samarium(III) oxide is a dense, high-melting rare-earth oxide. Suppliers list it for neutron absorbers in reactor control rods and for optical and infrared-absorbing glasses. Samarium is also on the USGS 2025 critical mineral list, so its supply is closely watched.",
    "uses": [
      {
        "where": "Neutron absorbers in reactor control rods (supplier listing)",
        "line": "Nanografi lists neutron absorber in control rods for nuclear power reactors among the important application areas of its Sm2O3 powder. No test result for this use was read."
      },
      {
        "where": "Optical and infrared-absorbing glasses",
        "line": "Nanografi lists optical and infrared-absorbing glasses as a further application area of the same powder."
      },
      {
        "where": "High-k dielectric research in MOS devices",
        "line": "The 2019 modelling paper says the most promising electronic device applications for Sm2O3 are MOS and ReRAM devices, and quotes a dielectric constant of up to 15 for amorphous films."
      }
    ],
    "can_do": [
      {
        "label": "Neutron absorber",
        "line": "Nanografi lists neutron absorber in control rods for nuclear power reactors as an application of its Sm2O3 powder. No test result for this use was read.",
        "scope": "material",
        "value": "Reactor control rods (supplier listing)"
      },
      {
        "label": "Optical glass",
        "line": "Nanografi lists optical and infrared-absorbing glasses as a further application of the same powder.",
        "scope": "material",
        "value": "Optical and infrared-absorbing glasses (supplier listing)"
      },
      {
        "label": "Melting point",
        "line": "The Thermo Fisher SDS prints a melting point of 2325 °C, and the Nanografi page prints 2335 °C for the same oxide.",
        "scope": "material",
        "value": "2325 °C (SDS) and 2335 °C (Nanografi)"
      }
    ],
    "compare": "Sm2O3 is a dense, high-melting oxide with a cubic crystal structure. PubChem gives 8.347 g/cm3 at 25 °C for its density, while the Nanografi page gives 8.43 g/cm3. Its melting point is printed as 2325 °C in the SDS and 2335 °C on the Nanografi page, and the modelling paper gives a calculated bulk modulus of 137.26 GPa for the cubic crystal. Its main space-relevant case is as a dielectric and optical material in research, with no flight record found.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Melting point",
        "benchmark": "melting_point",
        "scope": "material"
      },
      {
        "label": "Bulk modulus",
        "benchmark": "bulk_modulus",
        "scope": "material"
      }
    ],
    "handling": [
      "PubChem and the Thermo Fisher SDS both point to acid incompatibility. Keep the powder away from acids and strong oxidizing agents.",
      "The SDS asks for dry, tightly closed storage because the powder is hygroscopic.",
      "Avoid breathing dust, and handle in a closed system or with exhaust ventilation."
    ],
    "good_for": [
      "Optical and infrared-absorbing glass, as supplier listings describe.",
      "Research on high-k dielectrics, where the 2019 modelling paper quotes a dielectric constant of up to 15 for amorphous films."
    ],
    "watch_out": [
      "Two supplier melting points (2325 °C and 2335 °C) and two densities (8.347 and 8.43 g/cm3) differ, so check the source that matches the grade and form you need.",
      "PubChem's aquatic toxicity warnings and the SDS's not-hazardous classification disagree.",
      "No space or radiation test on Sm2O3 was found, so treat the neutron-absorber and glass uses as supplier claims."
    ],
    "verdict": "Sm2O3 is a dense, high-melting rare-earth oxide with useful supplier-listed uses in neutron absorbers and optical glasses, and a research record as a high-k dielectric. For space work it is unproven: no flight or radiation test was found, and the melting point and density values differ between sources.",
    "recipe": {
      "line": "Sm2O3 is samarium(III) oxide. Each formula unit combines two samarium atoms with three oxygen atoms, and PubChem gives the formula as O3Sm2 with a molecular weight of 348.7 g/mol.",
      "parts": [
        {
          "name": "Samarium",
          "symbol": "Sm",
          "role": "The metal centre, held in the +3 state in Sm2O3."
        },
        {
          "name": "Oxygen",
          "symbol": "O",
          "role": "Oxygen anions around each samarium. The 2019 modelling paper describes each Sm as six-coordinated in a distorted octahedron in the cubic crystal."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "PubChem's GHS record lists aquatic toxicity warnings, while the Thermo Fisher SDS calls the product not hazardous under OSHA.",
        "points": [
          {
            "label": "Aquatic",
            "line": "PubChem's GHS record gives the signal word Warning with H400 and H410 in 44.6 percent of company reports each."
          },
          {
            "label": "SDS",
            "line": "The Thermo Fisher SDS prints an oral LD50 greater than 5 g/kg in rat and no GHS label elements."
          },
          {
            "label": "Dust",
            "line": "Avoid breathing dust and use exhaust ventilation, as the SDS directs."
          }
        ],
        "level": 1,
        "verdict": "Hazard data conflict: PubChem and the SDS differ"
      },
      {
        "title": "Moisture and acids",
        "lead": "The SDS calls the powder air sensitive and hygroscopic, and lists acids as incompatible.",
        "points": [
          {
            "label": "Storage",
            "line": "Keep the container tightly closed in a dry, cool, well-ventilated place."
          },
          {
            "label": "Acids",
            "line": "PubChem describes the oxide as soluble in acids, so acid contact removes material."
          }
        ],
        "verdict": "Keep dry and away from acids"
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 13,
    "unreachable": 2,
    "caveats": 3,
    "note": "Drafted by an AI assistant on 2026-11-01 from pages opened in this run. Values are from PubChem, a Thermo Fisher SDS, two Nanografi product pages, a 2025 conference abstract and a 2019 open-access modelling paper, with USGS for supply. Two supplier values disagree on melting point and density and both are kept."
  },
  "sources": {
    "pubchem-sm2o3": {
      "title": "PubChem compound record, Samarium(III) oxide (CID 159425): Experimental Properties, Computed Properties, GHS Classification, Physical Description",
      "id": "CID 159425; CAS 12060-58-1",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/159425/JSON",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NCBI)"
    },
    "wsu-sm2o3-sds": {
      "title": "Thermo Fisher Scientific safety data sheet, Samarium(III) oxide, Cat. No. 36278, revision 29 March 2024 (hosted by Washington State University)",
      "id": "Cat. No. 36278; CAS 12060-58-1",
      "url": "https://wpcdn.web.wsu.edu/wp-research/uploads/sites/2909/2025/05/Samarium-III-Oxide-12060-58-1.pdf",
      "year": 2024,
      "kind": "datasheet",
      "license": "supplier safety data sheet, linked not reproduced"
    },
    "nanografi-sm2o3-powder": {
      "title": "Nanografi: Samarium oxide (Sm2O3) powder product page",
      "id": "supplier product page",
      "url": "https://shop.nanografi.com/rare-earth-materials/rare-earth-oxide-powder/samarium-oxide-sm2o3-powder/",
      "year": 2026,
      "kind": "web",
      "license": "supplier web page, linked not reproduced"
    },
    "nanografi-sm2o3-nano": {
      "title": "Nanografi: Samarium oxide nanoparticles product page",
      "id": "supplier product page",
      "url": "https://shop.nanografi.com/nanoparticles/single-metal-oxide-nanoparticles/samarium-oxide-nanoparticles/",
      "year": 2026,
      "kind": "web",
      "license": "supplier web page, linked not reproduced"
    },
    "usgs-mcs2026-rare-earths": {
      "title": "Mineral Commodity Summaries 2026, Rare Earths",
      "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-critical-2025": {
      "title": "About the 2025 List of Critical Minerals (USGS, final list of 60 minerals)",
      "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)"
    },
    "saip-sm2o3-poster": {
      "title": "Effect of Temperature on Structural and Optical Properties of Sm2O3 (SAIP 2025 conference contribution)",
      "id": "SAIP 2025, contribution 463",
      "url": "https://events2.saip.org.za/event/1/contributions/463/contribution.pdf",
      "year": 2025,
      "kind": "paper",
      "license": "conference abstract, linked not reproduced"
    },
    "olsson-cai-2019": {
      "title": "Structural, Elastic, Vibrational and Electronic Properties of Amorphous Sm2O3 from Ab Initio Calculations (Olsson, Cai, Cottom, Jakobsen, Shluger)",
      "id": "doi:10.1016/j.commatsci.2019.109119 (Computational Materials Science, 2019); UCL Discovery eprint 10084314",
      "url": "https://discovery.ucl.ac.uk/id/eprint/10084314/1/Revised%20Manuscript.pdf",
      "year": 2019,
      "kind": "paper",
      "license": "open access via UCL Discovery (as listed)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/samarium-oxide/"
}