{
  "spore": "profile",
  "id": "cadmium-sulfide",
  "spore_version": "0.2",
  "family": "ii-vi-semiconductors",
  "name": "Cadmium sulfide (CdS)",
  "abbreviation": "CdS",
  "role": "n-type window semiconductor and photoconductor",
  "category": "energy",
  "type": "solar-cells",
  "summary": "Cadmium sulfide (CdS) is a yellow inorganic compound with a direct band gap of 2.42 eV and a solid density of 4.826 g/cm3, both per Wikipedia. It is the n-type window layer in CdTe thin-film solar cells, where a review gives its band gap as 2.4 eV. Its conductivity rises under light, which is why it is used in photoresistors. A NASA review of thin-film cells says CdS is no longer considered for space applications. No flight, vacuum or radiation-test record for CdS was found in the sources read.\n",
  "best_for": "Thin n-type window layers in CdTe thin-film solar cells, and light-sensitive resistors (photoresistors)",
  "weakest_at": "Cadmium toxicity: dust is the main hazard, and the supplier safety data sheet classes the compound as carcinogenic and mutagenic. No space or radiation data for CdS was found.",
  "identity": {
    "formula": "CdS",
    "cas": "1306-23-6",
    "crystal_system": "hexagonal (wurtzite) and cubic (zinc blende) forms",
    "designations": [
      {
        "system": "Trade name",
        "code": "cadmium yellow",
        "source": "cds-wiki",
        "where": "Applications, Pigment section: 'known as cadmium yellow'"
      }
    ],
    "source": "cds-wiki",
    "where": "Chembox identifiers (CAS number 1306-23-6) and structure section (hexagonal wurtzite and cubic zinc blende forms)"
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "solar-arrays",
      "electronics-and-chips"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, solid (Wikipedia infobox)",
      "value": 4.826,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "state": "solid, as printed in the infobox",
        "temperature": "not printed on the page"
      },
      "method": "Infobox value printed as 4.826 g/cm3, solid",
      "status": "ground",
      "source": "cds-wiki",
      "where": "Infobox, Density row",
      "source_detail": {
        "title": "Cadmium sulfide (Wikipedia article, infobox and text)",
        "id": "CAS 1306-23-6; PubChem CID 14783; ChemSpider 7969586",
        "url": "https://en.wikipedia.org/wiki/Cadmium_sulfide",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA (Wikipedia)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, cubic form (PubChem)",
      "value": 4.5,
      "bound": "exact",
      "unit": "g/cu cm",
      "scope": "material",
      "conditions": {
        "structure": "cubic (zinc blende) form",
        "temperature": "not printed on the page"
      },
      "method": "Experimental property entry printed in the PubChem record",
      "status": "ground",
      "source": "pubchem-cds",
      "where": "Experimental Properties, Density entry 'Cubic structure: 4.50 g/cu cm'",
      "source_detail": {
        "title": "PubChem compound record, Cadmium Sulfide (CID 14783)",
        "id": "CID 14783; CAS 1306-23-6",
        "url": "https://pubchem.ncbi.nlm.nih.gov/compound/14783",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, hexagonal form (PubChem)",
      "value": 4.82,
      "bound": "exact",
      "unit": "g/cu cm",
      "scope": "material",
      "conditions": {
        "structure": "hexagonal (wurtzite) form",
        "temperature": "not printed on the page"
      },
      "method": "Experimental property entry printed in the PubChem record",
      "status": "ground",
      "source": "pubchem-cds",
      "where": "Experimental Properties, Density entry 'hexagonal structure: 4.82 g/cu cm'",
      "source_detail": {
        "title": "PubChem compound record, Cadmium Sulfide (CID 14783)",
        "id": "CID 14783; CAS 1306-23-6",
        "url": "https://pubchem.ncbi.nlm.nih.gov/compound/14783",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    },
    {
      "benchmark": "density",
      "label": "Relative density (supplier SDS)",
      "value": 4.82,
      "bound": "exact",
      "unit": "g/mL",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C"
      },
      "method": "Physical and chemical properties section of the supplier SDS, item m (relative density)",
      "status": "ground",
      "source": "sam-cds-sds",
      "where": "Section 9 (physical and chemical properties), item m, Relative density: 4.82 g/mL at 25 °C",
      "source_detail": {
        "title": "Safety Data Sheet: Cadmium sulfide (Stanford Advanced Materials, version 3.0, revision 09/04/2017)",
        "id": "SAM Materials, cadmium sulfide, CAS 1306-23-6",
        "url": "https://samaterials.com/tds/sc/1723107280-Joy-22-cd1111.pdf",
        "year": 2017,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point (Wikipedia infobox, at 10 MPa)",
      "value": 1750,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "pressure": "10 MPa, as printed in the infobox note"
      },
      "method": "Infobox value printed as 1,750 °C",
      "status": "ground",
      "source": "cds-wiki",
      "where": "Infobox, Melting point row, with note 10 MPa",
      "source_detail": {
        "title": "Cadmium sulfide (Wikipedia article, infobox and text)",
        "id": "CAS 1306-23-6; PubChem CID 14783; ChemSpider 7969586",
        "url": "https://en.wikipedia.org/wiki/Cadmium_sulfide",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA (Wikipedia)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point (AEM Deposition product table)",
      "value": 1750,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "pressure": "not stated on the product page"
      },
      "method": "Product specification table, row 'Melting Point (°C)' printed as 1,750",
      "status": "ground",
      "source": "aem-cds",
      "where": "Product specification table, Melting Point (°C) row",
      "source_detail": {
        "title": "Cadmium Sulfide Pellet Evaporation Material (CdS), AEM Deposition product page",
        "id": "AEM Deposition product listing, CdS compound evaporation material",
        "url": "https://www.aemdeposition.com/compound-evaporation-material/cadmium-sulfide-evaporation-material.html",
        "year": 2026,
        "kind": "web",
        "license": "supplier page, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point (PubChem, approximate)",
      "value": 1480,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "printed as approximately 1480 °C"
      },
      "method": "Experimental property entry in the PubChem record",
      "status": "ground",
      "note": "PubChem prints this value as approximate and disagrees with the two values above.",
      "source": "pubchem-cds",
      "where": "Experimental Properties, Melting Point entry",
      "source_detail": {
        "title": "PubChem compound record, Cadmium Sulfide (CID 14783)",
        "id": "CID 14783; CAS 1306-23-6",
        "url": "https://pubchem.ncbi.nlm.nih.gov/compound/14783",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point (supplier SDS)",
      "value": 999,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "printed as 999 °C (1,830 °F)"
      },
      "method": "Physical and chemical properties section of the supplier SDS, item e",
      "status": "ground",
      "note": "Disagrees with the Wikipedia and AEM values; the supplier does not give a test method.",
      "source": "sam-cds-sds",
      "where": "Section 9 (physical and chemical properties), item e, Melting point/range",
      "source_detail": {
        "title": "Safety Data Sheet: Cadmium sulfide (Stanford Advanced Materials, version 3.0, revision 09/04/2017)",
        "id": "SAM Materials, cadmium sulfide, CAS 1306-23-6",
        "url": "https://samaterials.com/tds/sc/1723107280-Joy-22-cd1111.pdf",
        "year": 2017,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "sublimation_point",
      "label": "Sublimation point",
      "value": 980,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "basis": "sublimes on heating; the ICSC card gives it as a sublimation point, not a boiling point"
      },
      "method": "Physical and chemical information section of the ICSC card, printed as 980°C",
      "status": "ground",
      "source": "icsc-0404",
      "where": "Physical and chemical information, Sublimation point row",
      "source_detail": {
        "title": "ICSC 0404: Cadmium sulfide (International Chemical Safety Card, ILO and WHO)",
        "id": "ICSC 0404; CAS 1306-23-6; UN 2570 as printed on the card",
        "url": "http://www.inchem.org/documents/icsc/icsc/eics0404.htm",
        "year": 2021,
        "kind": "datasheet",
        "license": "ILO and WHO, cited not reproduced"
      }
    },
    {
      "benchmark": "band_gap",
      "label": "Band gap, direct (Wikipedia)",
      "value": 2.42,
      "bound": "exact",
      "unit": "eV",
      "scope": "material",
      "conditions": {
        "gap_type": "direct, as the page states",
        "temperature": "not printed on the page"
      },
      "method": "Infobox BandGap value; the text reads 'direct band gap semiconductor (gap 2.42 eV)'",
      "status": "ground",
      "note": "Not in property-canon; a snake_case name is used.",
      "source": "cds-wiki",
      "where": "Infobox, BandGap row; Structure and physical properties section",
      "source_detail": {
        "title": "Cadmium sulfide (Wikipedia article, infobox and text)",
        "id": "CAS 1306-23-6; PubChem CID 14783; ChemSpider 7969586",
        "url": "https://en.wikipedia.org/wiki/Cadmium_sulfide",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA (Wikipedia)"
      }
    },
    {
      "benchmark": "band_gap",
      "label": "Band gap (CdS in a CdTe/CdS review)",
      "value": 2.4,
      "bound": "exact",
      "unit": "eV",
      "scope": "material",
      "conditions": {
        "basis": "stated in the same sentence as the CdTe band gap of 1.45 eV"
      },
      "method": "Printed in the introduction of a review of CdS window layers",
      "status": "ground",
      "note": "Not in property-canon; a snake_case name is used.",
      "source": "lilhare2020",
      "where": "Section 1 (Introduction), paragraph beginning 'Since the CdTe and CdS bandgaps'",
      "source_detail": {
        "title": "Development of chalcogenide solar cells: Importance of CdS window layer (Opto-Electronics Review 28, 43-63)",
        "id": "Opto-Electronics Review 28 (2020) 43-63; D. Lilhare and A. Khare",
        "url": "https://journals.pan.pl/Content/115768/PDF/OPELRE_28_1_D_LILHARE.pdf",
        "year": 2020,
        "kind": "paper",
        "license": "open access, as listed by the journal"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index (Wikipedia infobox)",
      "value": 2.529,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "wavelength": "not printed on the page"
      },
      "method": "Infobox RefractIndex value",
      "status": "ground",
      "source": "cds-wiki",
      "where": "Infobox, RefractIndex row",
      "source_detail": {
        "title": "Cadmium sulfide (Wikipedia article, infobox and text)",
        "id": "CAS 1306-23-6; PubChem CID 14783; ChemSpider 7969586",
        "url": "https://en.wikipedia.org/wiki/Cadmium_sulfide",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA (Wikipedia)"
      }
    },
    {
      "benchmark": "refractive_index",
      "label": "Refractive index (PubChem, first value)",
      "value": 2.506,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "wavelength": "not printed on the page",
        "basis": "printed as 'INDEX OF REFRACTION: 2.506; 2.529'"
      },
      "method": "Experimental property entry in the PubChem record",
      "status": "ground",
      "note": "PubChem prints two values for the same entry; the second matches the Wikipedia infobox.",
      "source": "pubchem-cds",
      "where": "Experimental Properties, Refractive Index entry",
      "source_detail": {
        "title": "PubChem compound record, Cadmium Sulfide (CID 14783)",
        "id": "CID 14783; CAS 1306-23-6",
        "url": "https://pubchem.ncbi.nlm.nih.gov/compound/14783",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    },
    {
      "benchmark": "standard_entropy",
      "label": "Standard entropy",
      "value": 65,
      "bound": "exact",
      "unit": "J/mol K",
      "scope": "material",
      "conditions": {
        "state": "standard state (25 °C, 100 kPa), as the page states for its data"
      },
      "method": "Thermochemistry infobox, citing a textbook",
      "status": "ground",
      "note": "Not in property-canon; a snake_case name is used.",
      "source": "cds-wiki",
      "where": "Infobox, Thermochemistry, Entropy row",
      "source_detail": {
        "title": "Cadmium sulfide (Wikipedia article, infobox and text)",
        "id": "CAS 1306-23-6; PubChem CID 14783; ChemSpider 7969586",
        "url": "https://en.wikipedia.org/wiki/Cadmium_sulfide",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA (Wikipedia)"
      }
    },
    {
      "benchmark": "molar_mass",
      "label": "Molecular weight",
      "value": 144.48,
      "bound": "exact",
      "unit": "g/mol",
      "scope": "material",
      "conditions": {
        "basis": "as printed in the supplier SDS for CdS"
      },
      "method": "Composition section of the supplier SDS",
      "status": "ground",
      "note": "Not in property-canon; a snake_case name is used.",
      "source": "sam-cds-sds",
      "where": "Section 3 (composition/information on ingredients), Molecular weight row",
      "source_detail": {
        "title": "Safety Data Sheet: Cadmium sulfide (Stanford Advanced Materials, version 3.0, revision 09/04/2017)",
        "id": "SAM Materials, cadmium sulfide, CAS 1306-23-6",
        "url": "https://samaterials.com/tds/sc/1723107280-Joy-22-cd1111.pdf",
        "year": 2017,
        "kind": "datasheet",
        "license": "supplier document, linked not reproduced"
      }
    },
    {
      "benchmark": "ld50_oral",
      "label": "Acute oral LD50, rat",
      "value": 7080,
      "bound": "exact",
      "unit": "mg/kg",
      "scope": "material",
      "conditions": {
        "species": "rat",
        "route": "oral"
      },
      "method": "Hazards infobox, LD50 row; the safety section also gives approximately 7,080 mg/kg in rats",
      "status": "ground",
      "note": "Not in property-canon; a snake_case name is used.",
      "source": "cds-wiki",
      "where": "Infobox, Hazards, LD50 row; Safety section",
      "source_detail": {
        "title": "Cadmium sulfide (Wikipedia article, infobox and text)",
        "id": "CAS 1306-23-6; PubChem CID 14783; ChemSpider 7969586",
        "url": "https://en.wikipedia.org/wiki/Cadmium_sulfide",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA (Wikipedia)"
      }
    },
    {
      "benchmark": "occupational_exposure_limit",
      "label": "OSHA permissible exposure limit, TWA as Cd",
      "value": 0.005,
      "bound": "exact",
      "unit": "mg/m3",
      "scope": "material",
      "conditions": {
        "basis": "OSHA 1910.1027 PEL, time-weighted average, expressed as cadmium"
      },
      "method": "Hazards infobox, PEL row; the SDS prints the same PEL",
      "status": "ground",
      "note": "Not in property-canon; a snake_case name is used.",
      "source": "cds-wiki",
      "where": "Infobox, Hazards, PEL row",
      "source_detail": {
        "title": "Cadmium sulfide (Wikipedia article, infobox and text)",
        "id": "CAS 1306-23-6; PubChem CID 14783; ChemSpider 7969586",
        "url": "https://en.wikipedia.org/wiki/Cadmium_sulfide",
        "year": 2026,
        "kind": "web",
        "license": "CC BY-SA (Wikipedia)"
      }
    },
    {
      "benchmark": "occupational_exposure_limit",
      "label": "ACGIH TLV, respirable fraction, TWA",
      "value": 0.002,
      "bound": "exact",
      "unit": "mg/m3",
      "scope": "material",
      "conditions": {
        "basis": "TLV as TWA, respirable fraction, as the ICSC card prints it"
      },
      "method": "Occupational exposure limits section of the ICSC card",
      "status": "ground",
      "note": "Not in property-canon; a snake_case name is used.",
      "source": "icsc-0404",
      "where": "Occupational exposure limits, TLV (respirable fraction) line",
      "source_detail": {
        "title": "ICSC 0404: Cadmium sulfide (International Chemical Safety Card, ILO and WHO)",
        "id": "ICSC 0404; CAS 1306-23-6; UN 2570 as printed on the card",
        "url": "http://www.inchem.org/documents/icsc/icsc/eics0404.htm",
        "year": 2021,
        "kind": "datasheet",
        "license": "ILO and WHO, cited not reproduced"
      }
    },
    {
      "benchmark": "solubility_product_log",
      "label": "Log solubility product (log Ksp)",
      "value": -14.36,
      "bound": "exact",
      "unit": "-",
      "scope": "material",
      "conditions": {
        "temperature": "25 °C",
        "pressure": "1 atm"
      },
      "method": "Other experimental properties entry in the PubChem record",
      "status": "ground",
      "note": "Not in property-canon; a snake_case name is used. PubChem also prints a second log K(sp) figure in its Solubility entry that is not recorded here, because it uses a different convention.",
      "source": "pubchem-cds",
      "where": "Experimental Properties, Other Experimental Properties entry 'log Ksp = -14.36 at 25 °C and 1 atm'",
      "source_detail": {
        "title": "PubChem compound record, Cadmium Sulfide (CID 14783)",
        "id": "CID 14783; CAS 1306-23-6",
        "url": "https://pubchem.ncbi.nlm.nih.gov/compound/14783",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    },
    {
      "benchmark": "oxidation_temperature",
      "label": "Heating in air that oxidizes CdS to sulfate and oxide",
      "value": 700,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "atmosphere": "air, especially in the presence of moisture"
      },
      "method": "Other experimental properties entry in the PubChem record",
      "status": "ground",
      "note": "Not in property-canon; a snake_case name is used.",
      "source": "pubchem-cds",
      "where": "Experimental Properties, Other Experimental Properties entry on oxidation in air",
      "source_detail": {
        "title": "PubChem compound record, Cadmium Sulfide (CID 14783)",
        "id": "CID 14783; CAS 1306-23-6",
        "url": "https://pubchem.ncbi.nlm.nih.gov/compound/14783",
        "year": 2026,
        "kind": "database",
        "license": "public domain (NCBI)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Heating in air, especially with moisture",
      "headline": "On heating in air to 700 °C, CdS oxidizes to a sulfate and then to the oxide.",
      "effect": "PubChem reports that CdS is oxidized to the sulfate, basic sulfate and eventually the oxide on heating in air to 700 °C, especially in the presence of moisture.",
      "rating": "moderate",
      "conditions": {
        "temperature": "700 °C",
        "atmosphere": "air with moisture"
      },
      "source": "pubchem-cds",
      "where": "Experimental Properties, Other Experimental Properties entry on oxidation"
    },
    {
      "environment": "Mineral acids",
      "headline": "CdS dissolves in acids and releases hydrogen sulfide.",
      "effect": "PubChem reports that CdS is soluble in concentrated or warm dilute mineral acids with evolution of H2S, and that moderately dilute nitric acid readily decomposes or dissolves it. Wikipedia gives the reaction with hydrochloric acid, which releases hydrogen sulfide.",
      "rating": "severe",
      "conditions": {
        "basis": "chemical attack, not a test of a film or coating"
      },
      "source": "pubchem-cds",
      "where": "Experimental Properties, Solubility entries"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Wikipedia prints the GHS signal word Danger for CdS with the H-phrases H302, H341, H350, H361, H372 and H413, and GHS pictograms GHS07 and GHS08.",
        "ghs": [
          "H302",
          "H341",
          "H350",
          "H361",
          "H372",
          "H413"
        ],
        "source": "cds-wiki",
        "where": "Hazards infobox (GHS signal word, H-phrases, pictograms)"
      },
      {
        "text": "The supplier safety data sheet (Stanford Advanced Materials, version 3.0) gives the signal word Danger with H302, H341, H350, H361, H372 and H410.",
        "ghs": [
          "H302",
          "H341",
          "H350",
          "H361",
          "H372",
          "H410"
        ],
        "source": "sam-cds-sds",
        "where": "Section 2, Hazards identification"
      },
      {
        "text": "PubChem's GHS summary for CID 14783 lists, for the compound, the signal word Danger with H302, H341 and H350. Its aggregated notifications also include H301 and H330 from some reports.",
        "ghs": [
          "H302",
          "H341",
          "H350"
        ],
        "source": "pubchem-cds",
        "where": "Safety and Hazards, GHS Classification"
      },
      {
        "text": "The ICSC card classes CdS as DANGER and says it may cause cancer, may cause damage to the kidneys, bones and respiratory tract through prolonged or repeated exposure, and may cause long-lasting harmful effects to aquatic life.",
        "ghs": [],
        "source": "icsc-0404",
        "where": "Classification and labelling, According to UN GHS Criteria"
      }
    ],
    "failure_risks": [
      {
        "mode": "Inhalation of dust",
        "trigger": "Powder dispersed in air during handling or weighing",
        "consequence": "The ICSC card says a harmful concentration of airborne particles can be reached quickly when the powder is dispersed. Prolonged or repeated exposure may affect the kidneys, bones and respiratory tract, and the substance is carcinogenic to humans.",
        "severity": "high",
        "source": "icsc-0404",
        "where": "Exposure and health effects section"
      },
      {
        "mode": "Oxidation on heating in air",
        "trigger": "Heating in air, especially with moisture",
        "consequence": "The compound is oxidized to sulfate and then oxide, which changes the material.",
        "severity": "moderate",
        "source": "pubchem-cds",
        "where": "Other experimental properties entry on oxidation"
      },
      {
        "mode": "Hydrogen sulfide release on contact with acid",
        "trigger": "Contact with mineral acids",
        "consequence": "The compound dissolves and releases hydrogen sulfide gas.",
        "severity": "high",
        "source": "pubchem-cds",
        "where": "Solubility entries"
      },
      {
        "mode": "Fire",
        "trigger": "Heat, flame or reaction with oxidizing agents",
        "consequence": "The ICSC card says it decomposes on burning to toxic fumes including sulfur oxides, and that as a dust it presents a moderate fire hazard.",
        "severity": "moderate",
        "source": "icsc-0404",
        "where": "Fire and explosion section; chemical dangers"
      }
    ],
    "side_effects": [
      {
        "text": "When dispersed CdS in sulfide solution is irradiated with light, hydrogen gas is generated, according to Wikipedia.",
        "affects": "Process chemistry of CdS suspensions",
        "source": "cds-wiki",
        "where": "Reactions section"
      }
    ],
    "handling": [
      {
        "text": "The ICSC card says to prevent dispersion of dust and avoid all contact, and to use local exhaust or breathing protection. Wear a particulate filter respirator adapted to the airborne concentration.",
        "source": "icsc-0404",
        "where": "Prevention and spillage disposal sections"
      },
      {
        "text": "Store separated from strong oxidants, strong acids and food, in an area without a drain or sewer access (ICSC card). The supplier SDS says keep it in a dry place.",
        "source": "icsc-0404",
        "where": "Storage section"
      },
      {
        "text": "Transport classification differs between sources. The supplier SDS prints \"UN number: 3077\" and \"Class: 9\"; the ICSC card prints \"UN #: 2570\" and \"UN Hazard Class: 6.1\".",
        "source": "sam-cds-sds",
        "where": "Section 14, Transport information; ICSC 0404 Transportation section"
      }
    ],
    "mitigations": [
      {
        "text": "PubChem notes that processes which release cadmium fumes or dust should be enclosed and fitted with exhaust ventilation, and that workers in over-exposure situations should wear a high-efficiency particulate filter respirator.",
        "source": "pubchem-cds",
        "where": "Hazards Summary, first record"
      }
    ]
  },
  "uses": [
    {
      "application": "solar-arrays",
      "device": "CdTe thin-film solar cells (window layer)",
      "example": "Wikipedia says CdS is used as a thin film in some solar cells. A review of CdS window layers says N-type CdS is one of the best-known transparent window layers in CdTe heterojunction cells, and gives its band gap as 2.4 eV.",
      "source": "lilhare2020",
      "where": "Section 1 (Introduction)"
    },
    {
      "application": "electronics-and-chips",
      "device": "Photoresistors (light-dependent resistors)",
      "example": "Wikipedia says the conductivity of CdS increases when it is irradiated, which is the basis of its use as a photoresistor. The NASA Radiation Effects Design Handbook says photoconductive cells that use the bulk effect are normally made of CdS or CdSe and have no junction.",
      "source": "cds-wiki",
      "where": "Structure and physical properties section; NASA handbook section 6 (ntrs-1971-drennan) gives the bulk-effect statement"
    },
    {
      "application": "solar-arrays",
      "device": "Thin-film CdS/Cu2S solar cells studied for spacecraft power (no longer a candidate)",
      "example": "A NASA review of radiation resistance says CdS/Cu2S solar cells have shown excellent radiation tolerance, but that cells of this type are no longer considered a potential candidate for photovoltaic power generation. It states that cadmium sulfide cells had been the subject of considerable effort but are no longer considered for space applications.",
      "source": "ntrs-1991-woodyard",
      "where": "Section 3.1 (electron irradiation resistance) and abstract"
    }
  ],
  "supply": [
    {
      "subject": "Cadmium",
      "abundance": "The USGS states that the cadmium content of typical zinc ores averages about 0.03%. No crustal abundance figure for cadmium was found in the sources read.",
      "producers": [
        {
          "country": "China",
          "share_percent": 41.3,
          "year": 2025
        },
        {
          "country": "Korea, Republic of",
          "share_percent": 18.7,
          "year": 2025
        },
        {
          "country": "Japan",
          "share_percent": 5.7,
          "year": 2025
        },
        {
          "country": "Canada",
          "share_percent": 5.7,
          "year": 2025
        },
        {
          "country": "Kazakhstan",
          "share_percent": 4.8,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "USGS 2025 List of Critical Minerals",
          "listed": false
        },
        {
          "list": "EU critical raw materials list (European Commission page)",
          "listed": false
        }
      ],
      "recycling": "USGS: secondary cadmium is mainly recovered from spent consumer and industrial NiCd batteries, and CdTe solar panels are named among the scrap from which cadmium can be recycled.",
      "substitutes": [
        "USGS: batteries with other chemistries, particularly lithium-ion, can replace NiCd batteries, and cerium sulfide is used as a replacement for cadmium pigments, mostly in plastics."
      ],
      "source": "usgs-mcs2026-cadmium",
      "where": "World Refinery Production and Reserves table, 2025e (shares calculated by Space Mushroom against the printed world total of 23,000 thousand t, rounded); Recycling; Substitutes; Resources"
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "USGS Mineral Commodity Summaries 2026, Cadmium",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-cadmium.pdf",
      "year": 2026
    },
    {
      "title": "PubChem: Cadmium Sulfide (CID 14783), GHS classification and experimental properties",
      "type": "database",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/14783",
      "year": 2026
    },
    {
      "title": "ICSC 0404: Cadmium sulfide (ILO and WHO International Chemical Safety Card)",
      "type": "datasheet",
      "url": "http://www.inchem.org/documents/icsc/icsc/eics0404.htm",
      "year": 2021
    },
    {
      "title": "Safety Data Sheet: Cadmium sulfide (Stanford Advanced Materials, version 3.0)",
      "type": "sds",
      "url": "https://samaterials.com/tds/sc/1723107280-Joy-22-cd1111.pdf",
      "year": 2017
    },
    {
      "title": "Radiation Resistance of Thin-Film Solar Cells for Space Photovoltaic Power (Woodyard and Landis, NASA)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/19910009863",
      "year": 1991
    },
    {
      "title": "Radiation Effects Design Handbook, Section 6: Solid-State Photodevices (Drennan, NASA contractor report)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/citations/19710023222",
      "year": 1971
    },
    {
      "title": "Development of chalcogenide solar cells: Importance of CdS window layer (Lilhare and Khare, Opto-Electronics Review)",
      "type": "paper",
      "url": "https://journals.pan.pl/Content/115768/PDF/OPELRE_28_1_D_LILHARE.pdf",
      "year": 2020
    }
  ],
  "gaps": [
    "No flight, vacuum, thermal-vacuum or radiation-test result for CdS was found. The only space-related sources are historical NASA reviews and a handbook section, and they describe the cells qualitatively.",
    "The NASA radiation reviews give fluences and efficiencies in exponent or spaced-letter form, which could not be matched reliably, so those numbers were left out. Their qualitative statements are quoted instead.",
    "The AEM evaporation table gives a source temperature for a vapour pressure printed with an exponent; this was left out.",
    "No crustal abundance figure for cadmium was found in the sources read.",
    "Sources disagree on the melting point (three values are recorded side by side), on the UN transport number, and on the aquatic hazard codes (the SDS and Wikipedia differ). Each value is kept with its source.",
    "No standards designation (UNS, EN, ASTM) for a CdS grade was found; only the pigment name cadmium yellow is listed.",
    "Thermal conductivity, specific heat, elastic modulus, dielectric constant and radiation tolerance numbers were not found in the sources read.",
    "No humidity or long-term ageing test data for CdS films were found in the sources read.",
    "Benchmark names outside property-canon (band_gap, enthalpy_of_formation, standard_entropy, molar_mass, ld50_oral, occupational_exposure_limit, sublimation_point, oxidation_temperature, solubility_product_log) are snake_case names.",
    "The critical-mineral lists were checked against the official pages in this run, and cadmium was not named on either page; no figure is recorded for those lists."
  ],
  "story": {
    "why": "Cadmium sulfide (CdS) is a yellow II-VI semiconductor compound. It forms a hexagonal wurtzite structure, which Wikipedia calls the more stable form, and a cubic zinc blende structure. CdS is used as the n-type window in CdTe thin-film solar cells, as a photoresistor, and as a yellow pigment. For space materials the interest is largely historical. NASA reviews of thin-film solar cells describe CdS cells as having been studied for spacecraft power, and say they are no longer considered for space applications.",
    "uses": [
      {
        "where": "Thin-film solar cells",
        "line": "N-type CdS is used as a transparent window layer in heterojunction cells paired with p-type CdTe. A review of CdS window layers gives the band gap of CdS as 2.4 eV."
      },
      {
        "where": "Photoresistors",
        "line": "The conductivity of CdS increases under light, which is the basis for its use in photoresistors (Wikipedia). A NASA handbook says photoconductive cells that use the bulk effect are normally made of CdS or CdSe and have no junction."
      },
      {
        "where": "Early space solar cells, no longer a candidate",
        "line": "A NASA review of radiation resistance says CdS/Cu2S cells have shown excellent radiation tolerance in electron tests. It also says that cadmium sulfide cells had been the subject of considerable effort but are no longer considered for space applications."
      }
    ],
    "can_do": [
      {
        "label": "Window layer",
        "line": "Works as the n-type window in CdTe thin-film solar cells, with a band gap of 2.4 eV in a review and 2.42 eV on Wikipedia.",
        "benchmark": "band_gap",
        "scope": "material"
      },
      {
        "label": "Photoresistor",
        "line": "Acts as a photoresistor, because its conductivity rises under light (Wikipedia).",
        "scope": "material"
      },
      {
        "label": "Pigment",
        "line": "Gives a yellow colour as a pigment; Wikipedia calls it cadmium yellow.",
        "scope": "material"
      },
      {
        "label": "Acid",
        "line": "Dissolves in mineral acids with release of hydrogen sulfide (PubChem).",
        "scope": "material"
      }
    ],
    "compare": "CdS is the wide-band-gap partner in a CdTe cell. Its band gap of 2.42 eV (Wikipedia) and 2.4 eV (review) lets photons with lower energy reach the CdTe absorber, according to the review. Melting-point sources disagree, so all three values are shown with their sources: 1750 °C (Wikipedia and the AEM product table), approximately 1480 °C (PubChem) and 999 °C (supplier SDS). The density values are close: 4.826 g/cm3 (Wikipedia) and 4.82 g/mL at 25 °C (supplier SDS).",
    "compare_rows": [
      {
        "label": "Band gap",
        "benchmark": "band_gap",
        "scope": "material"
      },
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Melting point",
        "benchmark": "melting_point",
        "scope": "material"
      }
    ],
    "handling": [
      "Prevent dust: the ICSC card says to prevent dispersion of dust and avoid all contact.",
      "Use local exhaust, and a particulate filter respirator adapted to the airborne concentration where dust may be present.",
      "Store dry and tightly closed, away from strong oxidants, strong acids and food.",
      "Keep it out of drains and the environment; the ICSC card says it is persistent and bioaccumulates in some organisms."
    ],
    "good_for": [
      "Thin-film window layers in CdTe cells, where a wide band gap is needed (review).",
      "Photoconductive cells, where its conductivity rises under light (Wikipedia)."
    ],
    "watch_out": [
      "Toxicity: a carcinogenic cadmium compound, with dust as the main exposure route.",
      "Melting point and transport classification differ between sources, so check the cited value.",
      "No flight, vacuum or radiation-test result for CdS was found; the space-related sources are historical reviews."
    ],
    "verdict": "CdS is a historic window and photoresistor material. Its cadmium toxicity and the NASA statement that CdS is no longer considered for space applications make it a poor choice for new flight hardware.",
    "recipe": {
      "line": "CdS is cadmium sulfide: one cadmium atom and one sulfur atom per formula unit. Pigment grade is made by precipitating from soluble cadmium salts with sulfide ion, washing the precipitate, then calcining (roasting) it to the hexagonal form before milling to a powder. Thin films are made by chemical bath deposition, using thiourea as the sulfide source (Wikipedia).",
      "parts": [
        {
          "name": "Cadmium",
          "symbol": "Cd",
          "role": "Divalent cation (Cd2+) in the crystal lattice; the cadmium content is what makes the compound toxic."
        },
        {
          "name": "Sulfur",
          "symbol": "S",
          "role": "Sulfide anion (S2-) that pairs with cadmium; it is released as hydrogen sulfide when the compound dissolves in acid."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "CdS is a cadmium compound. The supplier safety data sheet and Wikipedia both class it as carcinogenic and mutagenic, and inhaled dust is the main route of harm.",
        "points": [
          {
            "label": "Dust",
            "line": "The ICSC card says a harmful concentration of airborne particles can be reached quickly when the powder is dispersed. Use local exhaust or breathing protection."
          },
          {
            "label": "Kidneys, bones and lungs",
            "line": "Prolonged or repeated exposure may affect the kidneys, bones and respiratory tract (ICSC card)."
          },
          {
            "label": "Exposure limits",
            "line": "The OSHA permissible exposure limit is 0.005 mg/m3 as a time-weighted average, expressed as cadmium (Wikipedia). The ICSC card gives 0.002 mg/m3 for the respirable fraction."
          }
        ],
        "level": 0,
        "verdict": "Carcinogen as dust: keep dust out of the air"
      },
      {
        "title": "If the material is heated",
        "lead": "These are laboratory and handling facts, not field incident reports.",
        "points": [
          {
            "label": "In air",
            "line": "On heating in air to 700 °C, CdS oxidizes to a sulfate and then to the oxide, faster when moist (PubChem)."
          },
          {
            "label": "In a fire",
            "line": "The ICSC card says it decomposes on burning to toxic fumes, including sulfur oxides, and that as a dust it presents a moderate fire hazard."
          },
          {
            "label": "In acid",
            "line": "Mineral acids dissolve it and release hydrogen sulfide (PubChem)."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Storage",
            "line": "Store in a cool, well-ventilated area, separated from strong oxidants, strong acids and food (ICSC card)."
          },
          {
            "label": "Spills",
            "line": "Moisten the spill to prevent dusting, sweep it into covered containers, and do not let it enter the environment (ICSC card)."
          }
        ]
      }
    ]
  },
  "updated": "2026-11-02",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 20,
    "unreachable": 0,
    "caveats": 2,
    "note": "Written by an AI assistant on 2026-11-02 from pages read in this run. Values are as printed. Three melting-point values and two transport numbers disagree between sources and are recorded side by side."
  },
  "sources": {
    "cds-wiki": {
      "title": "Cadmium sulfide (Wikipedia article, infobox and text)",
      "id": "CAS 1306-23-6; PubChem CID 14783; ChemSpider 7969586",
      "url": "https://en.wikipedia.org/wiki/Cadmium_sulfide",
      "year": 2026,
      "kind": "web",
      "license": "CC BY-SA (Wikipedia)"
    },
    "aem-cds": {
      "title": "Cadmium Sulfide Pellet Evaporation Material (CdS), AEM Deposition product page",
      "id": "AEM Deposition product listing, CdS compound evaporation material",
      "url": "https://www.aemdeposition.com/compound-evaporation-material/cadmium-sulfide-evaporation-material.html",
      "year": 2026,
      "kind": "web",
      "license": "supplier page, cited not reproduced"
    },
    "usgs-mcs2026-cadmium": {
      "title": "Mineral Commodity Summaries 2026: Cadmium",
      "id": "USGS MCS 2026, February 2026",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-cadmium.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-crit-2025": {
      "title": "About the 2025 List of Critical Minerals (USGS final list)",
      "id": "Final 2025 List of Critical Minerals",
      "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals",
      "year": 2025,
      "kind": "web",
      "license": "public domain (USGS)"
    },
    "ec-crm": {
      "title": "Critical raw materials (European Commission, list under Regulation (EU) 2024/1252)",
      "id": "Regulation (EU) 2024/1252",
      "url": "https://single-market-economy.ec.europa.eu/sectors/raw-materials/areas-specific-interest/critical-raw-materials_en",
      "year": 2024,
      "kind": "web",
      "license": "European Commission web page"
    },
    "pubchem-cds": {
      "title": "PubChem compound record, Cadmium Sulfide (CID 14783)",
      "id": "CID 14783; CAS 1306-23-6",
      "url": "https://pubchem.ncbi.nlm.nih.gov/compound/14783",
      "year": 2026,
      "kind": "database",
      "license": "public domain (NCBI)"
    },
    "icsc-0404": {
      "title": "ICSC 0404: Cadmium sulfide (International Chemical Safety Card, ILO and WHO)",
      "id": "ICSC 0404; CAS 1306-23-6; UN 2570 as printed on the card",
      "url": "http://www.inchem.org/documents/icsc/icsc/eics0404.htm",
      "year": 2021,
      "kind": "datasheet",
      "license": "ILO and WHO, cited not reproduced"
    },
    "sam-cds-sds": {
      "title": "Safety Data Sheet: Cadmium sulfide (Stanford Advanced Materials, version 3.0, revision 09/04/2017)",
      "id": "SAM Materials, cadmium sulfide, CAS 1306-23-6",
      "url": "https://samaterials.com/tds/sc/1723107280-Joy-22-cd1111.pdf",
      "year": 2017,
      "kind": "datasheet",
      "license": "supplier document, linked not reproduced"
    },
    "ntrs-1991-woodyard": {
      "title": "Radiation Resistance of Thin-Film Solar Cells for Space Photovoltaic Power (Woodyard and Landis, NASA review)",
      "id": "NTRS 19910009863",
      "url": "https://ntrs.nasa.gov/citations/19910009863",
      "year": 1991,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "ntrs-1971-drennan": {
      "title": "Radiation Effects Design Handbook, Section 6: Solid-State Photodevices (Drennan, NASA contractor report)",
      "id": "NTRS 19710023222",
      "url": "https://ntrs.nasa.gov/citations/19710023222",
      "year": 1971,
      "kind": "report",
      "license": "public domain (NASA)"
    },
    "lilhare2020": {
      "title": "Development of chalcogenide solar cells: Importance of CdS window layer (Opto-Electronics Review 28, 43-63)",
      "id": "Opto-Electronics Review 28 (2020) 43-63; D. Lilhare and A. Khare",
      "url": "https://journals.pan.pl/Content/115768/PDF/OPELRE_28_1_D_LILHARE.pdf",
      "year": 2020,
      "kind": "paper",
      "license": "open access, as listed by the journal"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/cadmium-sulfide/"
}