{
  "spore": "profile",
  "id": "arsenic-trisulfide",
  "spore_version": "0.2",
  "family": "chalcogenide-glass",
  "name": "Arsenic trisulfide",
  "abbreviation": "As2S3",
  "role": "infrared optical glass",
  "category": "glasses-optics",
  "type": "optical-crystals",
  "summary": "Arsenic trisulfide (As2S3) is an arsenic-sulfur chalcogenide glass that transmits infrared light from about 620 nm to 11 µm, according to a UCF/CREOL paper. AZoM lists its density as 3.46 g/cm3 and its melting point as 310 °C. The supplier safety data sheet classifies the powder as toxic if swallowed or if inhaled, so it is an infrared optics material that needs strict handling.",
  "best_for": "Infrared windows and laser-written micro-structures, where the infrared window matters more than low toxicity",
  "weakest_at": "Toxicity: the arsenic content makes it a hazardous material to handle, store and dispose of",
  "identity": {
    "formula": "As2S3",
    "cas": "1303-33-9",
    "crystal_system": "monoclinic",
    "designations": [],
    "source": "azom-as2s3",
    "where": "Chemical Properties table (Chemical Formula, CAS No. and Crystal Structure rows)"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "optics-and-cameras"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "value": 3.46,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "basis": "no temperature, form or test condition printed on the page"
      },
      "method": "Value printed in the Mechanical Properties table of the AZoM article",
      "status": "ground",
      "note": "Apollo Scientific also prints 3.43 g/cm3 (recorded below). Wikipedia's 3.43 g/cm3 is not recorded (see gaps).",
      "source": "azom-as2s3",
      "where": "Mechanical Properties table, Density row",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "value": 3.43,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "basis": "product page for Apollo Scientific catalogue IN1166 (99.999%); no temperature printed"
      },
      "method": "Value printed in the physical data section of the Apollo Scientific product page",
      "status": "ground",
      "note": "Differs from the AZoM value of 3.46 g/cm3 (see gaps).",
      "source": "apollo-as2s3",
      "where": "Physical data, Density",
      "source_detail": {
        "title": "Arsenic(III) sulfide, 99.999%, catalogue IN1166 (Apollo Scientific product page)",
        "id": "Apollo Scientific catalogue IN1166; CAS 1303-33-9",
        "url": "https://store.apolloscientific.co.uk/product/arseniciii-sulfide",
        "kind": "datasheet",
        "license": "supplier product page, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "value": 310,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "no condition printed on the page"
      },
      "method": "Value printed in the Mechanical Properties table of the AZoM article",
      "status": "ground",
      "source": "azom-as2s3",
      "where": "Mechanical Properties table, Melting Point row",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "value": 300,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "product page for Apollo Scientific catalogue IN1166 (99.999%); no condition printed"
      },
      "method": "Value printed in the physical data section of the Apollo Scientific product page",
      "status": "ground",
      "note": "Differs from the AZoM value of 310 °C (see gaps).",
      "source": "apollo-as2s3",
      "where": "Physical data, Melting point",
      "source_detail": {
        "title": "Arsenic(III) sulfide, 99.999%, catalogue IN1166 (Apollo Scientific product page)",
        "id": "Apollo Scientific catalogue IN1166; CAS 1303-33-9",
        "url": "https://store.apolloscientific.co.uk/product/arseniciii-sulfide",
        "kind": "datasheet",
        "license": "supplier product page, cited not reproduced"
      }
    },
    {
      "benchmark": "boiling_point",
      "value": 707,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "no condition printed on the page"
      },
      "method": "Value printed in the Mechanical Properties table of the AZoM article",
      "status": "ground",
      "source": "azom-as2s3",
      "where": "Mechanical Properties table, Boiling Point row",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "refractive_index",
      "value": 2.4,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "wavelength": "not printed on the page"
      },
      "method": "Value printed in the Optical Properties table of the AZoM article",
      "status": "ground",
      "note": "The page gives no wavelength. Wikipedia gives 2.45 with no condition; the two disagree (see gaps).",
      "source": "azom-as2s3",
      "where": "Optical Properties table, Refractive Index row",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "mohs_hardness",
      "value": 1.8,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "scale": "Mohs scale, a dimensionless ranking; no unit printed"
      },
      "method": "Value printed in the Mechanical Properties table of the AZoM article",
      "status": "ground",
      "source": "azom-as2s3",
      "where": "Mechanical Properties table, Mohs Hardness row",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "molar_heat_capacity",
      "value": 116.3,
      "bound": "exact",
      "unit": "J/mol K",
      "scope": "material",
      "conditions": {
        "basis": "printed as Specific Heat Capacity in molar units; not converted to per kilogram"
      },
      "method": "Value printed in the Thermal Properties table of the AZoM article",
      "status": "ground",
      "source": "azom-as2s3",
      "where": "Thermal Properties table, Specific Heat Capacity row",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "standard_molar_entropy",
      "value": 163.6,
      "bound": "exact",
      "unit": "J/mol K",
      "scope": "material",
      "conditions": {
        "basis": "standard molar entropy as printed; no reference temperature stated"
      },
      "method": "Value printed in the Thermal Properties table of the AZoM article",
      "status": "ground",
      "source": "azom-as2s3",
      "where": "Thermal Properties table, Standard molar entropy row",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "heat_of_formation",
      "value": -169,
      "bound": "exact",
      "unit": "kJ/mol",
      "scope": "material",
      "conditions": {
        "basis": "no reference state or temperature printed on the page"
      },
      "method": "Value printed in the Thermal Properties table of the AZoM article",
      "status": "ground",
      "source": "azom-as2s3",
      "where": "Thermal Properties table, Heat of Formation row",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "lattice_constant_a",
      "value": 11.49,
      "bound": "exact",
      "unit": "Å",
      "scope": "material",
      "conditions": {
        "crystal_system": "monoclinic",
        "temperature": "not printed on the page"
      },
      "method": "Value printed in the Chemical Properties table of the AZoM article",
      "status": "ground",
      "source": "azom-as2s3",
      "where": "Chemical Properties table, Lattice Constant row (a)",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "lattice_constant_b",
      "value": 9.59,
      "bound": "exact",
      "unit": "Å",
      "scope": "material",
      "conditions": {
        "crystal_system": "monoclinic",
        "temperature": "not printed on the page"
      },
      "method": "Value printed in the Chemical Properties table of the AZoM article",
      "status": "ground",
      "source": "azom-as2s3",
      "where": "Chemical Properties table, Lattice Constant row (b)",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "lattice_constant_c",
      "value": 4.25,
      "bound": "exact",
      "unit": "Å",
      "scope": "material",
      "conditions": {
        "crystal_system": "monoclinic",
        "temperature": "not printed on the page"
      },
      "method": "Value printed in the Chemical Properties table of the AZoM article",
      "status": "ground",
      "source": "azom-as2s3",
      "where": "Chemical Properties table, Lattice Constant row (c)",
      "source_detail": {
        "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
        "id": "AZoM ArticleID 8438",
        "url": "https://www.azom.com/article.aspx?ArticleID=8438",
        "kind": "web",
        "license": "AZoM article, cited not reproduced"
      }
    },
    {
      "benchmark": "molecular_weight",
      "value": 246,
      "bound": "exact",
      "unit": "g/mol",
      "scope": "material",
      "conditions": {
        "basis": "computed by PubChem 2.1, not measured"
      },
      "method": "Computed value printed in the PubChem record for CID 4093503 (Molecular Weight section)",
      "status": "calculated",
      "source": "pubchem-as2s3",
      "where": "Molecular Weight section of the PubChem record (CID 4093503)",
      "source_detail": {
        "title": "PubChem compound record, Arsenic (III) sulfide (CID 4093503), JSON view",
        "id": "CID 4093503; CAS 1303-33-9",
        "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/4093503/JSON",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    },
    {
      "benchmark": "ir_transmission_lower_wavelength",
      "label": "Shortest wavelength transmitted (infrared window, lower limit)",
      "value": 620,
      "bound": "lower",
      "unit": "nm",
      "scope": "material",
      "conditions": {
        "basis": "stated as approximately 620 nm in the paper",
        "material": "As2S3 glass as described in the paper; bulk and film not separated"
      },
      "method": "Value stated in the abstract and introduction of the UCF/CREOL paper",
      "status": "ground",
      "source": "ucf-as2s3",
      "where": "Abstract; Section 1 (Introduction), first paragraph",
      "source_detail": {
        "title": "Processing and properties of arsenic trisulfide chalcogenide glasses for direct laser writing of 3D micro-structures",
        "id": "Schwarz, Williams, Grabill, Lewis, Kuebler et al., University of Central Florida (CREOL)",
        "url": "https://api.creol.ucf.edu/Publications/7446.pdf",
        "kind": "paper",
        "license": "open PDF; licence not stated on the document"
      }
    },
    {
      "benchmark": "ir_transmission_upper_wavelength",
      "label": "Longest wavelength transmitted (infrared window, upper limit)",
      "value": 11,
      "bound": "upper",
      "unit": "µm",
      "scope": "material",
      "conditions": {
        "basis": "stated as the upper end of the infrared transparency range",
        "material": "As2S3 glass as described in the paper"
      },
      "method": "Value stated in the abstract and introduction of the UCF/CREOL paper",
      "status": "ground",
      "source": "ucf-as2s3",
      "where": "Abstract; Section 1 (Introduction), first paragraph",
      "source_detail": {
        "title": "Processing and properties of arsenic trisulfide chalcogenide glasses for direct laser writing of 3D micro-structures",
        "id": "Schwarz, Williams, Grabill, Lewis, Kuebler et al., University of Central Florida (CREOL)",
        "url": "https://api.creol.ucf.edu/Publications/7446.pdf",
        "kind": "paper",
        "license": "open PDF; licence not stated on the document"
      }
    },
    {
      "benchmark": "ld50_oral_rat",
      "label": "Acute oral LD50, rat",
      "value": 185,
      "bound": "exact",
      "unit": "mg/kg",
      "scope": "material",
      "conditions": {
        "species": "rat",
        "route": "oral",
        "product": "arsenic sulfide (As2S3) powder, per the supplier SDS"
      },
      "method": "Acute oral LD50 printed in the toxicological information section of the supplier SDS",
      "status": "ground",
      "source": "samaterials-sds",
      "where": "Section 11, Acute toxicity (LD/LC50 values relevant for classification)",
      "source_detail": {
        "title": "Safety data sheet: arsenic sulfide (As2S3) powder (supplier SDS)",
        "id": "Supplier SDS, product file 1697118961-2645",
        "url": "https://samaterials.com/tds/1697118961-2645-arsenic-sulfide-as2s3-powder-sds.pdf",
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "ld50_dermal_rat",
      "label": "Acute dermal LD50, rat",
      "value": 936,
      "bound": "exact",
      "unit": "mg/kg",
      "scope": "material",
      "conditions": {
        "species": "rat",
        "route": "dermal",
        "product": "arsenic sulfide (As2S3) powder, per the supplier SDS"
      },
      "method": "Acute dermal LD50 printed in the toxicological information section of the supplier SDS",
      "status": "ground",
      "source": "samaterials-sds",
      "where": "Section 11, Acute toxicity (LD/LC50 values relevant for classification)",
      "source_detail": {
        "title": "Safety data sheet: arsenic sulfide (As2S3) powder (supplier SDS)",
        "id": "Supplier SDS, product file 1697118961-2645",
        "url": "https://samaterials.com/tds/1697118961-2645-arsenic-sulfide-as2s3-powder-sds.pdf",
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Air, oxidation of the glass",
      "headline": "The glass form resists oxidation better than the crystalline form, according to Wikipedia.",
      "effect": "Wikipedia states that the arsenic trisulfide glass is more resistant to oxidation than crystalline arsenic trisulfide, which minimizes toxicity concerns. The page gives no oxidation rate, humidity or temperature for this statement.",
      "rating": "low",
      "conditions": {
        "basis": "qualitative statement only; no test conditions printed"
      },
      "source": "wikipedia-as2s3",
      "where": "Section on IR-transmitting glasses"
    },
    {
      "environment": "Aged samples of the material",
      "headline": "Aged samples can contain soluble arsenic oxides, which Wikipedia calls highly toxic.",
      "effect": "Wikipedia states that aged samples can contain substantial amounts of arsenic oxides, which are soluble and therefore highly toxic. No ageing time, temperature or humidity is given.",
      "rating": "moderate",
      "conditions": {
        "basis": "qualitative statement only; no ageing conditions printed"
      },
      "source": "wikipedia-as2s3",
      "where": "Safety section"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Supplier SDS for arsenic sulfide (As2S3) powder: signal word Danger, pictogram GHS06, hazard statements H301 (toxic if swallowed) and H331 (toxic if inhaled).",
        "ghs": [
          "H301",
          "H331"
        ],
        "source": "samaterials-sds",
        "where": "Section 2, GHS label elements"
      },
      {
        "text": "AZoM lists H301 (toxic if swallowed), H331 (toxic if inhaled) and H410 (very toxic to aquatic life with long lasting effects) for arsenic trisulfide.",
        "ghs": [
          "H301",
          "H331",
          "H410"
        ],
        "source": "azom-as2s3",
        "where": "Safety Information, GHS Hazard Statements list"
      },
      {
        "text": "Apollo Scientific (catalogue IN1166) lists H330 (fatal if inhaled) and H301+H311 (toxic if swallowed or in contact with skin), with a GHS06 pictogram. Its H330 differs from H331 (toxic if inhaled) in the SDS and AZoM; both are kept.",
        "ghs": [
          "H330",
          "H301",
          "H311"
        ],
        "source": "apollo-as2s3",
        "where": "Product page, hazard statements and pictogram"
      },
      {
        "text": "The supplier SDS prints carcinogen classifications for this material: IARC-1 (carcinogenic to humans), ACGIH A1 (confirmed human carcinogen) and NTP-K (known to be carcinogenic).",
        "ghs": [],
        "source": "samaterials-sds",
        "where": "Section 11, Carcinogenicity"
      }
    ],
    "failure_risks": [
      {
        "mode": "Delamination from thermal expansion (chalcogenide glasses in general)",
        "trigger": "Temperature change on a bonded or constrained component",
        "consequence": "The UCF/CREOL paper says a high coefficient of thermal expansion can cause component failure through delamination, so temperature control becomes necessary. The paper is about chalcogenide glasses in general and gives no expansion value for As2S3.",
        "severity": "moderate",
        "source": "ucf-as2s3",
        "where": "Section 1 (Introduction), second paragraph"
      },
      {
        "mode": "Release of soluble arsenic oxides from aged samples",
        "trigger": "Storage or ageing of the material",
        "consequence": "Soluble arsenic oxides, which Wikipedia calls highly toxic, can be present in aged samples.",
        "severity": "high",
        "source": "wikipedia-as2s3",
        "where": "Safety section"
      }
    ],
    "side_effects": [
      {
        "text": "The supplier SDS lists arsenic oxides, toxic metal oxide fume, sulfur oxides and hydrogen sulfide as hazardous decomposition products.",
        "affects": "People near a fire or during overheating",
        "source": "samaterials-sds",
        "where": "Section 10, Hazardous decomposition products"
      }
    ],
    "handling": [
      {
        "text": "AZoM precautions: avoid breathing dust, fume, gas, mist, vapours or spray (P261); avoid release to the environment (P273); dispose of contents and container at an approved waste disposal plant (P501).",
        "source": "azom-as2s3",
        "where": "Safety Precautions list"
      },
      {
        "text": "NIOSH pocket guide entry for arsenic, inorganic compounds (as As), which Wikipedia cites for this material: OSHA PEL printed as [1910.1018] TWA 0.010 mg/m3; NIOSH REL printed as Ca C 0.002 mg/m3 [15-minute]; IDLH printed as Ca [5 mg/m3 (as As)].",
        "source": "niosh-npg-0038",
        "where": "Exposure limits, PEL, REL and IDLH rows"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "optics-and-cameras",
      "device": "Infrared-transmitting glass for optics and sensors",
      "example": "The UCF/CREOL paper describes As2S3 as an infrared transparent material with direct applications in IR sensors, photonic waveguides and acousto-optics.",
      "source": "ucf-as2s3",
      "where": "Abstract; Section 1 (Introduction)"
    },
    {
      "application": "optics-and-cameras",
      "device": "Photoresist for laser-written three-dimensional micro-structures (laboratory use)",
      "example": "The UCF/CREOL paper reports that thermally deposited As2S3 films can be photo-patterned like polymeric photoresists, and that woodpile photonic crystals, nanowires and waveguides have been fabricated in As2S3 by direct laser writing.",
      "source": "ucf-as2s3",
      "where": "Section 1 (Introduction)"
    },
    {
      "application": "optics-and-cameras",
      "device": "Infrared seeker nose cone of the de Havilland Firestreak missile (historic)",
      "example": "Wikipedia records that arsenic trisulfide was used for the eight-sided conical nose over the infrared seeker of the de Havilland Firestreak missile.",
      "source": "wikipedia-as2s3",
      "where": "History section (Contemporary uses, IR-transmitting glasses)"
    }
  ],
  "supply": [
    {
      "subject": "Arsenic (as arsenic trioxide, the arsenic product USGS reports; As2S3 itself is not reported separately)",
      "producers": [
        {
          "country": "Peru",
          "share_percent": 49.2,
          "year": 2025
        },
        {
          "country": "China",
          "share_percent": 39.3,
          "year": 2025
        },
        {
          "country": "Morocco",
          "share_percent": 8.2,
          "year": 2025
        },
        {
          "country": "Belgium",
          "share_percent": 1.6,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 0.8,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: arsenic metal was contained in new scrap recycled during GaAs semiconductor manufacturing, and no arsenic was known to have been recovered from scrap electronic circuit boards, relays and switches.",
      "substitutes": [],
      "source": "usgs-mcs2026-arsenic",
      "where": "World Production and Capacity table, 2025 column of production (arsenic trioxide, gross weight); shares calculated by Space Mushroom against the printed world total of 61,000; Recycling section"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Safety data sheet: arsenic sulfide (As2S3) powder (supplier SDS)",
      "type": "sds",
      "url": "https://samaterials.com/tds/1697118961-2645-arsenic-sulfide-as2s3-powder-sds.pdf"
    },
    {
      "title": "Processing and properties of arsenic trisulfide chalcogenide glasses for direct laser writing of 3D micro-structures (UCF/CREOL, open PDF)",
      "type": "paper",
      "url": "https://api.creol.ucf.edu/Publications/7446.pdf"
    },
    {
      "title": "Mineral Commodity Summaries 2026: Arsenic (USGS)",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-arsenic.pdf",
      "year": 2026
    },
    {
      "title": "PubChem compound record: Arsenic (III) sulfide (CID 4093503)",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/4093503",
      "year": 2026
    }
  ],
  "gaps": [
    "No flight, vacuum, radiation or space-environment result for arsenic trisulfide was found, and no space application source was read.",
    "No glass transition temperature and no coefficient of thermal expansion for As2S3 was found in a source we could open. The UCF/CREOL paper's expansion statement is qualitative and about chalcogenide glasses in general.",
    "Band gap of 2.7 eV (direct) is printed only in Wikipedia, which this profile uses for composition, history and qualitative statements. It is not recorded as a property.",
    "Density: AZoM gives 3.46 g/cm3 and Apollo Scientific gives 3.43 g/cm3; both are recorded side by side. Wikipedia gives 3.43 g/cm3 at standard state (25 °C and 100 kPa) and refractive index 2.45 with no condition; the Wikipedia values are not recorded as properties.",
    "Melting point: AZoM gives 310 °C and Apollo Scientific gives 300 °C; both are recorded side by side.",
    "Inhalation hazard code: Apollo Scientific lists H330 (fatal if inhaled); the SDS and AZoM list H331 (toxic if inhaled). Both are kept in the hazard list.",
    "The AZoM refractive index has no wavelength. A bulk-glass refractive index at a stated wavelength was not found in a source we could open; the Knotek et al. 2020 paper and the Makovetsky article could not be opened.",
    "Magnetic susceptibility is printed with an exponent in Wikipedia and without a unit in AZoM, so it is not recorded.",
    "No trade name, AMTIR designation or grade code is printed in the sources read. The lane note mentions AMTIR-6, but no source read here names it for this material, so no designation is listed.",
    "Fibre drawing, moulding and processing temperatures for As2S3 were not found in the sources read.",
    "Crustal abundance of arsenic was not found in a source we could open.",
    "The USGS arsenic chapter read here does not state whether arsenic is on the USGS or EU critical-mineral lists, so no list status is recorded.",
    "The USGS production data cover arsenic trioxide, not As2S3. Producer shares are calculated from printed tonnages.",
    "PubChem's GHS classification page was blocked in this run (reCAPTCHA), so no PubChem hazard codes are recorded. Wikipedia also lists H300, H400 and H411, which the supplier SDS, AZoM and Apollo Scientific do not print; they are not recorded as hazards.",
    "NIOSH exposure limits are for arsenic, inorganic compounds (as As), not separately for As2S3.",
    "Element atomic weights for arsenic and sulfur were not taken from a fetched source, so the recipe gives atom counts only.",
    "Taxonomy has no chalcogenide type. optical-crystals is the nearest infrared-optics slug.",
    "Non-canonical benchmark names used: molar_heat_capacity, standard_molar_entropy, heat_of_formation, mohs_hardness, lattice_constant_a, lattice_constant_b, lattice_constant_c, molecular_weight, ir_transmission_lower_wavelength, ir_transmission_upper_wavelength, ld50_oral_rat and ld50_dermal_rat."
  ],
  "story": {
    "why": "Arsenic trisulfide (As2S3) is a chalcogenide glass that transmits infrared light from about 620 nm to 11 µm, according to a UCF/CREOL paper. Designers use that window for infrared sensors and laser-written photonic structures. The same arsenic chemistry makes the material toxic, so every use comes with handling limits.",
    "uses": [
      {
        "where": "Infrared optics and sensors",
        "line": "A UCF/CREOL paper describes As2S3 as an infrared transparent material with direct applications in IR sensors, photonic waveguides and acousto-optics."
      },
      {
        "where": "Photoresist for laser-written micro-structures",
        "line": "The same paper reports that As2S3 films can be patterned by laser like polymeric photoresists, and that woodpile photonic crystals, nanowires and waveguides have been made in it by direct laser writing."
      },
      {
        "where": "A historic missile nose cone",
        "line": "Wikipedia records that arsenic trisulfide was used for the eight-sided conical nose over the infrared seeker of the de Havilland Firestreak missile."
      }
    ],
    "can_do": [
      {
        "label": "Infrared transmission",
        "line": "Transmits infrared light from about 620 nm to 11 µm, according to the UCF/CREOL paper.",
        "scope": "material"
      },
      {
        "label": "Density",
        "line": "AZoM lists a density of 3.46 g/cm3, with no temperature printed.",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Melting point",
        "line": "AZoM lists a melting point of 310 °C.",
        "benchmark": "melting_point",
        "scope": "material"
      },
      {
        "label": "Acute toxicity",
        "line": "The supplier SDS gives an oral LD50 of 185 mg/kg in rats, which is why the powder is toxic if swallowed.",
        "benchmark": "ld50_oral_rat",
        "scope": "material"
      }
    ],
    "compare": "Arsenic trisulfide is an infrared glass like the other optical materials in this group, but its chemistry is different: it is an arsenic sulfide, not an oxide. Wikipedia states that the glass form resists oxidation better than the crystalline form. The table sets its density, melting point and refractive index side by side.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Melting point",
        "benchmark": "melting_point",
        "scope": "material"
      },
      {
        "label": "Refractive index",
        "benchmark": "refractive_index",
        "scope": "material"
      }
    ],
    "handling": [
      "Keep dust and fume out of the air. AZoM's precautions say to avoid breathing dust, fume, gas, mist, vapours or spray.",
      "The NIOSH limits for arsenic, inorganic compounds (as As) are 0.010 mg/m3 for the OSHA PEL and 0.002 mg/m3 as the 15-minute NIOSH REL.",
      "Keep the material out of the environment, and send waste to an approved disposal plant."
    ],
    "good_for": [
      "Infrared windows and sensors that need transmission from about 620 nm to 11 µm (UCF/CREOL paper).",
      "Laser-written micro-structures, where As2S3 films act as an inorganic photoresist (UCF/CREOL paper)."
    ],
    "watch_out": [
      "Toxic if swallowed or inhaled (SDS: H301 and H331). AZoM also lists H410, very toxic to aquatic life.",
      "Aged samples can contain soluble arsenic oxides, which Wikipedia calls highly toxic.",
      "Sources disagree on the inhalation hazard code: H330 (fatal if inhaled) on the Apollo Scientific page, and H331 (toxic if inhaled) in the SDS and AZoM. Both are kept."
    ],
    "verdict": "Arsenic trisulfide is a useful infrared glass for optics and laser-written micro-structures, but its arsenic content makes it a hazardous material that needs strict handling.",
    "recipe": {
      "line": "Arsenic trisulfide is As2S3: two arsenic atoms and three sulfur atoms per formula unit. The UCF/CREOL paper describes thin films deposited by thermal evaporation of the bulk glass.",
      "parts": [
        {
          "name": "Arsenic",
          "symbol": "As",
          "role": "The heavy element that gives the glass its high refractive index and its toxicity."
        },
        {
          "name": "Sulfur",
          "symbol": "S",
          "role": "The network former that bonds to arsenic and holds the glass together."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The supplier SDS classifies the powder as toxic if swallowed or inhaled and prints carcinogen classifications for it.",
        "points": [
          {
            "label": "Swallowed or inhaled",
            "line": "The supplier SDS lists H301 (toxic if swallowed) and H331 (toxic if inhaled). Apollo Scientific lists H330 (fatal if inhaled) for the same compound."
          },
          {
            "label": "Cancer classification",
            "line": "The SDS prints IARC-1 (carcinogenic to humans) and ACGIH A1 (confirmed human carcinogen)."
          },
          {
            "label": "Dust and fume",
            "line": "AZoM advises avoiding breathing dust, fume, gas, mist, vapours or spray (P261)."
          }
        ],
        "level": 0,
        "verdict": "Toxic if swallowed or inhaled"
      },
      {
        "title": "If the material ages or burns",
        "lead": "These statements are qualitative. The sources do not give ageing or heating conditions.",
        "points": [
          {
            "label": "Aged samples",
            "line": "Wikipedia says aged samples can contain soluble arsenic oxides, which it calls highly toxic."
          },
          {
            "label": "Fire",
            "line": "The SDS lists arsenic oxides, sulfur oxides and hydrogen sulfide as hazardous decomposition products."
          }
        ],
        "verdict": "Aged samples can release arsenic oxides"
      },
      {
        "title": "Handling and storage",
        "lead": "The exposure limits below are for arsenic, inorganic compounds (as As), which the NIOSH pocket guide covers.",
        "points": [
          {
            "label": "Exposure limits",
            "line": "The OSHA PEL is 0.010 mg/m3 as a TWA, and the NIOSH REL is Ca C 0.002 mg/m3 over 15 minutes."
          },
          {
            "label": "Environment",
            "line": "Avoid release to the environment (P273) and send waste to an approved disposal plant (P501)."
          }
        ],
        "verdict": "Follow the arsenic exposure limits"
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 18,
    "unreachable": 6,
    "caveats": 3,
    "note": "Read by an AI assistant on 2026-11-01. Eight sources were read. Candidate sources that could not be opened from this environment: ECHA (HTTP 403), DTIC, Springer (login redirect), RSC Advances (HTTP 403), the Makovetsky article and the JOAM PDFs."
  },
  "sources": {
    "azom-as2s3": {
      "title": "Arsenic trisulfide, AZoM materials article (ArticleID 8438)",
      "id": "AZoM ArticleID 8438",
      "url": "https://www.azom.com/article.aspx?ArticleID=8438",
      "kind": "web",
      "license": "AZoM article, cited not reproduced"
    },
    "wikipedia-as2s3": {
      "title": "Arsenic trisulfide (Wikipedia)",
      "id": "Wikipedia, Arsenic trisulfide",
      "url": "https://en.wikipedia.org/wiki/Arsenic_trisulfide",
      "kind": "web",
      "license": "CC BY-SA 4.0 (Wikipedia text)"
    },
    "ucf-as2s3": {
      "title": "Processing and properties of arsenic trisulfide chalcogenide glasses for direct laser writing of 3D micro-structures",
      "id": "Schwarz, Williams, Grabill, Lewis, Kuebler et al., University of Central Florida (CREOL)",
      "url": "https://api.creol.ucf.edu/Publications/7446.pdf",
      "kind": "paper",
      "license": "open PDF; licence not stated on the document"
    },
    "usgs-mcs2026-arsenic": {
      "title": "Mineral Commodity Summaries 2026: Arsenic",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-arsenic.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "pubchem-as2s3": {
      "title": "PubChem compound record, Arsenic (III) sulfide (CID 4093503), JSON view",
      "id": "CID 4093503; CAS 1303-33-9",
      "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/4093503/JSON",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NCBI)"
    },
    "samaterials-sds": {
      "title": "Safety data sheet: arsenic sulfide (As2S3) powder (supplier SDS)",
      "id": "Supplier SDS, product file 1697118961-2645",
      "url": "https://samaterials.com/tds/1697118961-2645-arsenic-sulfide-as2s3-powder-sds.pdf",
      "kind": "datasheet",
      "license": "supplier document, linked not reproduced"
    },
    "apollo-as2s3": {
      "title": "Arsenic(III) sulfide, 99.999%, catalogue IN1166 (Apollo Scientific product page)",
      "id": "Apollo Scientific catalogue IN1166; CAS 1303-33-9",
      "url": "https://store.apolloscientific.co.uk/product/arseniciii-sulfide",
      "kind": "datasheet",
      "license": "supplier product page, cited not reproduced"
    },
    "niosh-npg-0038": {
      "title": "NIOSH Pocket Guide to Chemical Hazards: Arsenic, inorganic compounds (as As)",
      "id": "NIOSH NPG entry 0038 (page reviewed 30 October 2019)",
      "url": "https://www.cdc.gov/niosh/npg/npgd0038.html",
      "year": 2019,
      "kind": "handbook",
      "license": "public domain (US government)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/arsenic-trisulfide/"
}