{
  "spore": "profile",
  "id": "calcium-hexaboride",
  "spore_version": "0.2",
  "family": "carbide-nitride-boride-ceramics",
  "name": "Calcium hexaboride",
  "abbreviation": "CaB6",
  "role": "hard boride powder used as a copper deoxidiser, refractory additive and neutron-protection material",
  "category": "ceramics",
  "type": "ultra-high-temperature-ceramics",
  "summary": "Calcium hexaboride (CaB6, CAS 12007-99-7) is a black cubic boride powder. Vendor datasheets give a relative density of 2.33 g/cm3 and a melting point of 2230 °C, and a supplier safety data sheet gives 2235 °C. Matsushita and Komarneni (1999) report that hot-pressed CaB6 begins to oxidise at 1273 K. Suppliers sell it as a deoxidiser for high-conductivity copper and as a boron additive for refractories.\n",
  "best_for": "Deoxidising copper melts and adding boron to refractories, where the boride is a powder and an oxidation start near 1273 K is acceptable",
  "weakest_at": "Oxidation in air from 1273 K (hot-pressed sintered body) and reaction with strong oxidising agents; no hardness or electrical value with a printed unit was found in a source read",
  "identity": {
    "formula": "CaB6",
    "cas": "12007-99-7",
    "crystal_system": "cubic",
    "space_group": "Pm-3m",
    "designations": [
      {
        "system": "Trade name",
        "code": "Calcium boride",
        "source": "samaterials-sds-cab6",
        "where": "Section 1, Trade Name line"
      },
      {
        "system": "Trade name",
        "code": "Calcium hexaboride",
        "source": "beantown-sds-cab6",
        "where": "Section 1, Trade name line"
      }
    ],
    "source": "aflow-cab6",
    "where": "AFLOW prototype A6B_cP7_221_e_b-001 (CaB6): Pearson symbol cP7, space group Pm-3m (No. 221); CAS 12007-99-7 from samaterials-sds-cab6, Section 3"
  },
  "tags": {
    "environments": [],
    "stresses": [
      "extreme-heat"
    ],
    "applications": [
      "radiation-shielding",
      "electronics-and-chips",
      "structures"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Relative density, CaB6 powder (Heeger Materials)",
      "value": 2.33,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "powder, product HM-CaB6 series",
        "temperature": "not stated"
      },
      "method": "Printed as \"Relative density\" with the value 2.33 and the unit g/cm (the superscript 3 is missing on the page); the unit is taken as g/cm3 by convention, and the printed form is kept in the source",
      "status": "ground",
      "source": "heeger-cab6",
      "where": "Product page, More info text and property list (Relative density)",
      "source_detail": {
        "title": "Heeger Materials, Calcium Hexaboride (CaB6) Powder product page (reference HMBP-1321)",
        "url": "https://heegermaterials.com/boride-powders/1321-calcium-hexaboride-cab6-powder.html",
        "kind": "web",
        "license": "vendor web page, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Relative density, CaB6 powder (FUSnano)",
      "value": 2.33,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "powder, CaB6 grades MI325 and MI325L",
        "temperature": "not stated"
      },
      "method": "Printed as \"Relative density: 2.33g/cm\" on the product page (unit printed without the superscript 3)",
      "status": "ground",
      "source": "fusnano-cab6",
      "where": "Product page, property list (Relative density)",
      "source_detail": {
        "title": "FUSnano, Calcium Hexaboride Powder product page",
        "url": "https://www.fusnano.com/boride/calcium-hexaboride-powder.html",
        "kind": "web",
        "license": "vendor web page, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density at 20 °C, calcium boride (BeanTown SDS)",
      "value": 2.3,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "temperature": "20 °C",
        "form": "solid, powder"
      },
      "method": "Section 9 of the safety data sheet, printed as \"Density at 20 °C (68 °F): 2.3 g/cm³\"",
      "status": "ground",
      "source": "beantown-sds-cab6",
      "where": "Section 9, Physical and chemical properties",
      "source_detail": {
        "title": "BeanTown Chemical, Safety Data Sheet, Calcium hexaboride (article 216185), printed 07/09/2024",
        "url": "https://s3.amazonaws.com/beantown/216185.pdf",
        "kind": "datasheet",
        "license": "supplier SDS, cited not reproduced"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, calcium boride (Stanford Advanced Materials SDS)",
      "value": 2.3,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "powder",
        "temperature": "not stated"
      },
      "method": "Section 9 of the safety data sheet, printed as \"Density: 2.3 g/cc\" (unit g/cc read as g/cm3)",
      "status": "ground",
      "source": "samaterials-sds-cab6",
      "where": "Section 9, Physical and Chemical Characteristics",
      "source_detail": {
        "title": "Stanford Advanced Materials, Safety Data Sheet, Calcium Boride (CaB6)",
        "url": "https://samaterials.com/tds/sc/1735206667-BR0228.pdf",
        "kind": "datasheet",
        "license": "supplier SDS, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, CaB6 powder (Heeger Materials, More info text)",
      "value": 2230,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "powder",
        "atmosphere": "not stated"
      },
      "method": "Printed as \"2230℃\" in the More info text of the product page",
      "status": "ground",
      "note": "The same product page gives 2200 °C in its bulleted property list. The two values are kept side by side.",
      "source": "heeger-cab6",
      "where": "Product page, More info text (Melting point)",
      "source_detail": {
        "title": "Heeger Materials, Calcium Hexaboride (CaB6) Powder product page (reference HMBP-1321)",
        "url": "https://heegermaterials.com/boride-powders/1321-calcium-hexaboride-cab6-powder.html",
        "kind": "web",
        "license": "vendor web page, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, CaB6 powder (Heeger Materials, bulleted list)",
      "value": 2200,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "powder",
        "atmosphere": "not stated"
      },
      "method": "Printed as \"2200°C\" in the bulleted property list of the same product page",
      "status": "ground",
      "note": "Conflicts with the 2230 °C value on the same page; kept so that the conflict is visible.",
      "source": "heeger-cab6",
      "where": "Product page, bulleted list (Melting point)",
      "source_detail": {
        "title": "Heeger Materials, Calcium Hexaboride (CaB6) Powder product page (reference HMBP-1321)",
        "url": "https://heegermaterials.com/boride-powders/1321-calcium-hexaboride-cab6-powder.html",
        "kind": "web",
        "license": "vendor web page, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, CaB6 powder (FUSnano)",
      "value": 2230,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "powder",
        "atmosphere": "not stated"
      },
      "method": "Printed as \"2230 ℃\" in the property list of the product page",
      "status": "ground",
      "source": "fusnano-cab6",
      "where": "Product page, property list (Melting point)",
      "source_detail": {
        "title": "FUSnano, Calcium Hexaboride Powder product page",
        "url": "https://www.fusnano.com/boride/calcium-hexaboride-powder.html",
        "kind": "web",
        "license": "vendor web page, cited not reproduced"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point, calcium boride (Stanford Advanced Materials SDS)",
      "value": 2235,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "black powder"
      },
      "method": "Section 9 of the safety data sheet, printed as \"Melting Point: 2235 °C\"",
      "status": "ground",
      "note": "The BeanTown Chemical safety data sheet for the same CaB6 product lists the melting point as \"Undetermined\" (Section 9).",
      "source": "samaterials-sds-cab6",
      "where": "Section 9, Physical and Chemical Characteristics",
      "source_detail": {
        "title": "Stanford Advanced Materials, Safety Data Sheet, Calcium Boride (CaB6)",
        "url": "https://samaterials.com/tds/sc/1735206667-BR0228.pdf",
        "kind": "datasheet",
        "license": "supplier SDS, cited not reproduced"
      }
    },
    {
      "benchmark": "molar_mass",
      "label": "Molecular weight, CaB6",
      "value": 104.94,
      "bound": "exact",
      "unit": "g/mol",
      "scope": "material",
      "conditions": {
        "basis": "CaB6 formula weight as printed on the specification sheet"
      },
      "method": "Printed as \"Molecular weight 104.94 g/mol\" on the specification sheet (not a measured value); a custom property name, as it is not in spores/property-canon.yaml",
      "status": "calculated",
      "source": "molekula-spec-cab6",
      "where": "Page 1, header table and product table (Molecular weight)",
      "source_detail": {
        "title": "Molekula Ltd, Technical Data Sheet, Calcium hexaboride (product 90027985)",
        "url": "https://molekula.com/specification/90027985.pdf",
        "kind": "datasheet",
        "license": "supplier specification, cited not reproduced"
      }
    },
    {
      "benchmark": "molar_mass",
      "label": "Molecular weight, calcium boride (Stanford Advanced Materials SDS)",
      "value": 104.94,
      "bound": "exact",
      "unit": "g/mol",
      "scope": "material",
      "conditions": {
        "form": "powder, CaB6 (100 wt%)"
      },
      "method": "Section 9 of the safety data sheet, printed as \"Molecular weight: 104.94 g/mol\"; a custom property name",
      "status": "ground",
      "source": "samaterials-sds-cab6",
      "where": "Section 9, Physical and Chemical Characteristics",
      "source_detail": {
        "title": "Stanford Advanced Materials, Safety Data Sheet, Calcium Boride (CaB6)",
        "url": "https://samaterials.com/tds/sc/1735206667-BR0228.pdf",
        "kind": "datasheet",
        "license": "supplier SDS, cited not reproduced"
      }
    },
    {
      "benchmark": "oxidation_onset_temp",
      "label": "Oxidation start temperature, hot-pressed CaB6 sintered body",
      "value": 1273,
      "bound": "exact",
      "unit": "K",
      "scope": "material",
      "conditions": {
        "sample": "hot-pressed CaB6 sintered body",
        "atmosphere": "not stated in the abstract",
        "time": "not stated in the abstract"
      },
      "method": "Quoted in the abstract: \"The oxidation of samples started at 1273 K\"; the abstract gives no weight-gain magnitude. Custom property name; the start of oxidation, not a service limit",
      "status": "ground",
      "note": "The abstract gives weight gain rising with oxidation temperature but no magnitude. A separate 2009 abstract for a nickel-sintered CaB6 reports catastrophic oxidation from 1273 K; it was not read in full and is not used.",
      "source": "matsushita-1999",
      "where": "Abstract",
      "source_detail": {
        "title": "Matsushita J and Komarneni S, High temperature oxidation behavior of CaB6 sintered body, Journal of Materials Science 34(13), 3043-3046 (1999)",
        "url": "https://pure.psu.edu/en/publications/high-temperature-oxidation-behavior-of-cabsub6sub-sintered-body/",
        "kind": "paper",
        "license": "research-output record (abstract read)"
      }
    },
    {
      "benchmark": "purity",
      "label": "Purity, CaB6 powder grade (Heeger Materials, vendor grade)",
      "value": 99.9,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "vendor data sheet grade HM-CaB6 (200 mesh, 500 mesh and 20 µm listed)",
        "basis": "vendor product grade, not an intrinsic property of CaB6"
      },
      "method": "Printed as \"Purity: 99.9%\" in the data sheet section of the product page",
      "status": "ground",
      "source": "heeger-cab6",
      "where": "Product page, data sheet (Purity)",
      "source_detail": {
        "title": "Heeger Materials, Calcium Hexaboride (CaB6) Powder product page (reference HMBP-1321)",
        "url": "https://heegermaterials.com/boride-powders/1321-calcium-hexaboride-cab6-powder.html",
        "kind": "web",
        "license": "vendor web page, cited not reproduced"
      }
    },
    {
      "benchmark": "purity",
      "label": "Purity, CaB6 powder (FUSnano general range)",
      "value": 99,
      "value_high": 99.9,
      "bound": "range",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "basis": "general range offered by the vendor; the page's table also lists a grade with purity of 95% or more",
        "grade": "general range"
      },
      "method": "Printed as \"Purity (general): 99% - 99.9%\" on the product page; vendor claim, not a test result",
      "status": "ground",
      "note": "The FUSnano table lists a lower-purity grade (CaB6-MI325L), so this range is not the lowest grade offered.",
      "source": "fusnano-cab6",
      "where": "Product page, general product description (Purity)",
      "source_detail": {
        "title": "FUSnano, Calcium Hexaboride Powder product page",
        "url": "https://www.fusnano.com/boride/calcium-hexaboride-powder.html",
        "kind": "web",
        "license": "vendor web page, cited not reproduced"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Air at high temperature (hot-pressed CaB6 sintered body)",
      "headline": "Oxidation starts near 1273 K in a hot-pressed sintered body, and weight gain rises with temperature.",
      "effect": "Matsushita and Komarneni (1999) investigated the high-temperature oxidation of hot-pressed CaB6 to judge its use at high temperature. The oxidation of samples started at 1273 K, and weight gain increased with oxidation temperature. The abstract gives no atmosphere, time or weight-gain magnitude.",
      "rating": "moderate",
      "conditions": {
        "sample": "hot-pressed CaB6 sintered body",
        "atmosphere": "not stated in the abstract",
        "time": "not stated in the abstract"
      },
      "source": "matsushita-1999",
      "where": "Abstract"
    },
    {
      "environment": "Water, acids, alkali and strong oxidants (temperatures and concentrations not stated)",
      "headline": "CaB6 is insoluble in water and in some acids, but strong oxidants attack it.",
      "effect": "The Heeger Materials page says the powder is stable in air at high temperature, is insoluble in hydrochloric, hydrofluoric and dilute sulfuric acid, does not react with water, and is attacked by strong oxidants such as chlorine, fluorine, nitric acid and hydrogen peroxide. It reacts very slowly with alkali. The BeanTown SDS also says it is insoluble in water and dissolves slowly in acids.",
      "rating": "low",
      "conditions": {
        "basis": "vendor product page and supplier SDS; test temperatures and concentrations not given"
      },
      "source": "heeger-cab6",
      "where": "Product page, chemical resistance statement"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Supplier safety data sheet (Stanford Advanced Materials, Calcium Boride): classified with hazard statements H315 (causes skin irritation), H319 (causes serious eye irritation) and H335 (may cause respiratory irritation); signal word Warning.",
        "ghs": [
          "H315",
          "H319",
          "H335"
        ],
        "source": "samaterials-sds-cab6",
        "where": "Section 2, Hazards Identification"
      },
      {
        "text": "BeanTown Chemical safety data sheet for calcium hexaboride (OSHA HCS format): skin irritation category 2 (H315) and serious eye irritation category 2A (H319). It gives no H335 entry.",
        "ghs": [
          "H315",
          "H319"
        ],
        "source": "beantown-sds-cab6",
        "where": "Section 2, Hazard(s) identification, GHS classification"
      }
    ],
    "failure_risks": [
      {
        "mode": "Oxidation of hot-pressed CaB6 in air",
        "trigger": "Heating a hot-pressed sintered body in air from about 1273 K",
        "consequence": "Oxidation starts at 1273 K and weight gain rises with temperature (Matsushita and Komarneni 1999). The abstract does not report the oxidation products or their phases.",
        "severity": "moderate",
        "source": "matsushita-1999",
        "where": "Abstract"
      },
      {
        "mode": "Moisture agglomeration of the powder",
        "trigger": "Long exposure to moist air",
        "consequence": "The vendor says long air exposure can cause moisture agglomeration, so the powder should be stored sealed in a dry, cool place.",
        "severity": "low",
        "source": "heeger-cab6",
        "where": "Product page, storage statement"
      },
      {
        "mode": "Reaction with strong oxidising agents",
        "trigger": "Contact with oxidising agents",
        "consequence": "The safety data sheet lists oxidizing agents as the substance it reacts with, and says it is stable under recommended storage conditions.",
        "severity": "moderate",
        "source": "samaterials-sds-cab6",
        "where": "Section 10, Reactivity"
      }
    ],
    "side_effects": [
      {
        "text": "On decomposition the Stanford Advanced Materials safety data sheet lists borane and boron oxides and calcium oxide as hazardous decomposition products.",
        "affects": "Surrounding material and people in a fire or thermal decomposition",
        "source": "samaterials-sds-cab6",
        "where": "Section 10, Hazardous Decomposition Products"
      }
    ],
    "handling": [
      {
        "text": "Keep the container tightly closed in a dry, cool, well-ventilated place away from moisture and oxidising agents (Stanford Advanced Materials SDS and vendor pages).",
        "source": "samaterials-sds-cab6",
        "where": "Section 7, Storage Conditions"
      },
      {
        "text": "Vacuum up spills with a HEPA filter and place them in a closed container, taking care not to raise dust (Stanford Advanced Materials SDS).",
        "source": "samaterials-sds-cab6",
        "where": "Section 6, Accidental Release Measures"
      },
      {
        "text": "Wear a dust respirator, rubber gloves and safety glasses or goggles (Stanford Advanced Materials SDS, PPE section).",
        "source": "samaterials-sds-cab6",
        "where": "Section 8, Exposure Controls"
      }
    ],
    "mitigations": [
      {
        "text": "Avoid long air exposure and heavy pressure on the powder, and keep it away from oxidants (Heeger Materials product page).",
        "source": "heeger-cab6",
        "where": "Product page, storage and handling statements"
      }
    ]
  },
  "uses": [
    {
      "application": "electronics-and-chips",
      "device": "Deoxidiser for high-conductivity (oxygen-free) copper melts",
      "example": "The vendor says CaB6 is a deoxidising and degassing agent for high-conductivity copper. The page gives no test result or copper conductivity value.",
      "source": "heeger-cab6",
      "where": "Product page, applications list (deoxidizing and degassing agent for high-conductivity copper)"
    },
    {
      "application": "radiation-shielding",
      "device": "Neutron-protection material in the nuclear industry",
      "example": "The FUSnano page lists CaB6 as a neutron protection material for the nuclear industry. No neutron cross-section or shielding thickness is given on the page.",
      "source": "fusnano-cab6",
      "where": "Product page, applications list"
    },
    {
      "application": "structures",
      "device": "Boron additive for dolomite carbon and magnesia dolomite refractories",
      "example": "The Heeger Materials page lists CaB6 as a boron-containing additive for dolomite and magnesium dolomite refractories; the FUSnano page lists the same use for dolomite carbon and magnesia dolomite carbon refractories.",
      "source": "heeger-cab6",
      "where": "Product page, applications list"
    }
  ],
  "supply": [
    {
      "subject": "Boron (the boron half of CaB6)",
      "abundance": "USGS 2026: the 2025 world production total is withheld (XX), so shares are not calculated. 2025 production as printed: Turkey 1,500 thousand t of refined borates, Bolivia 380 thousand t of ulexite, Peru 220 thousand t of crude borates, and China 230 thousand t as boric oxide equivalent.",
      "producers": [],
      "critical_lists": [
        {
          "list": "USGS Final 2025 List of Critical Minerals, published 7 Nov 2025 (boron added in the 2025 list)",
          "listed": true
        }
      ],
      "recycling": "USGS: insignificant.",
      "substitutes": [
        "USGS: boron can be substituted in detergents, enamels, insulation and soaps (the chapter does not discuss boride powders)."
      ],
      "source": "usgs-mcs2026-boron",
      "where": "World Production and Reserves table, 2025 column; Recycling; Substitutes; Events, Trends and Issues (critical minerals paragraph)"
    },
    {
      "subject": "Calcium",
      "abundance": "Not found in any source read in this run.",
      "producers": [],
      "critical_lists": [],
      "recycling": "Not found in any source read in this run.",
      "substitutes": [],
      "source": "usgs-mcs2026-boron",
      "where": "Left empty. No calcium producer or feedstock source was read; the USGS boron chapter does not cover calcium."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "Heeger Materials, Calcium Hexaboride (CaB6) Powder product page",
      "type": "datasheet",
      "url": "https://heegermaterials.com/boride-powders/1321-calcium-hexaboride-cab6-powder.html",
      "year": 2026
    },
    {
      "title": "FUSnano, Calcium Hexaboride Powder product page",
      "type": "datasheet",
      "url": "https://www.fusnano.com/boride/calcium-hexaboride-powder.html",
      "year": 2026
    },
    {
      "title": "Stanford Advanced Materials, Safety Data Sheet, Calcium Boride (CaB6)",
      "type": "sds",
      "url": "https://samaterials.com/tds/sc/1735206667-BR0228.pdf",
      "year": 2024
    },
    {
      "title": "BeanTown Chemical, Safety Data Sheet, Calcium hexaboride (article 216185, reviewed 07/08/2024)",
      "type": "sds",
      "url": "https://s3.amazonaws.com/beantown/216185.pdf",
      "year": 2024
    },
    {
      "title": "Molekula Ltd, Technical Data Sheet, Calcium hexaboride (product 90027985, v1)",
      "type": "datasheet",
      "url": "https://molekula.com/specification/90027985.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026, Boron",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-boron.pdf",
      "year": 2026
    },
    {
      "title": "Matsushita J and Komarneni S, High temperature oxidation behavior of CaB6 sintered body, J. Mater. Sci. 34(13), 3043-3046",
      "type": "paper",
      "url": "https://pure.psu.edu/en/publications/high-temperature-oxidation-behavior-of-cabsub6sub-sintered-body/",
      "year": 1999
    },
    {
      "title": "Lee B and Wang L-W, Electronic Structure of Calcium Hexaborides (Lawrence Berkeley National Laboratory, eScholarship)",
      "type": "paper",
      "url": "https://escholarship.org/content/qt0370311w/qt0370311w.pdf",
      "year": 2005
    },
    {
      "title": "AFLOW Encyclopedia of Crystallographic Prototypes, A6B_cP7_221_e_b-001 (CaB6)",
      "type": "database",
      "url": "https://aflow.org/p/A6B_cP7_221_e_b-001",
      "year": 2026
    }
  ],
  "gaps": [
    "No hardness value with a printed unit was found in a source read. The Heeger Materials page gives a hardness figure with no scale or unit, so it is left out. Wikipedia's microhardness figure is not used because Wikipedia is limited to composition and history here.",
    "No thermal conductivity, electrical resistivity, elastic modulus or thermal expansion value for CaB6 was found in a source read in this run.",
    "The vendor's Curie temperature claim for spintronic use (Heeger Materials page) is not used: no test source was read and the vendor gives no measurement method.",
    "Melting point is not settled: 2200 °C and 2230 °C are both printed on the Heeger Materials page, FUSnano gives 2230 °C, the Stanford Advanced Materials SDS gives 2235 °C, and the BeanTown SDS lists it as Undetermined. Wikipedia's melting point figure is not used.",
    "Density is 2.33 g/cm3 from two vendor pages and 2.3 g/cm3 from two SDS documents; a higher Wikipedia density figure is not used.",
    "Calcium supply and producers: no source read in this run. The supply entry for calcium is empty.",
    "The PubChem record (CID 16212529, named in Wikipedia) could not be opened: the browser check blocked the page. The GHS hazard entries rest on two supplier safety data sheets, not on PubChem's aggregated classification.",
    "Copper deoxidation performance is not tested here. The 3M datasheet returned HTTP 403, and no copper conductivity figure was read from a fetched page. Only the vendor's use statement is recorded.",
    "The 1999 oxidation abstract gives no atmosphere, time or weight-gain magnitude. A 2009 abstract for nickel-sintered CaB6 reports fast oxidation from 1273 K but was not read in full, so it is not used.",
    "The 2019 high-pressure CaB6 study (cpb.iphy.ac.cn) returned a 404 page, so its lattice and bulk-modulus values are not used.",
    "Lattice constant and internal parameter x are not recorded as properties. The 2005 LBNL paper (Lee and Wang) gives an experimental lattice-constant range and an internal-parameter range, but its eScholarship copy blocked the automated check (HTTP 403), so the values could not be matched to the page. The paper is kept as a source for the crystal-structure text only.",
    "No UNS, EN, DIN, JIS or AISI designation is printed for CaB6 in a source read. The EC number 234-525-3 is printed on two SDS documents but is not in the designation systems this profile uses.",
    "Hazard data rest on two supplier safety data sheets; both report H315, H319 and H335 or H315 and H319, and neither gives toxicology values.",
    "No space flight or space-environment test of CaB6 was found in a source read. Its listed use in spacecraft or nuclear shielding is a vendor claim with no test data."
  ],
  "story": {
    "why": "Calcium hexaboride (CaB6) is a cubic boride powder. Vendors sell it for three jobs: as a deoxidiser that removes oxygen from copper melts, as a boron additive for refractories, and as a neutron-protection material. The vendors' data sheets and the two supplier SDS documents agree on a density of 2.3 to 2.33 g/cm3 and a melting point of 2230 °C to 2235 °C. The 1999 oxidation abstract sets the main limit: oxidation starts at 1273 K in air.",
    "uses": [
      {
        "where": "Copper refining",
        "line": "The vendor says CaB6 is a deoxidising and degassing agent for high-conductivity copper. The page gives no test result for the copper."
      },
      {
        "where": "Refractories",
        "line": "Vendors add CaB6 as a boron-containing additive to dolomite and magnesia dolomite refractories (vendor pages)."
      },
      {
        "where": "Nuclear shielding",
        "line": "FUSnano lists CaB6 as a neutron protection material for the nuclear industry. No shielding value is given on the page."
      }
    ],
    "can_do": [
      {
        "label": "Melt deoxidation",
        "line": "The vendor says it is used as a deoxidising and degassing agent for high-conductivity copper. The page gives no test result for the copper.",
        "scope": "material"
      },
      {
        "label": "Air limit",
        "line": "Oxidation in air starts at 1273 K for a hot-pressed sintered body (Matsushita and Komarneni 1999). Above that temperature it is not a suitable choice for air exposure, according to this one abstract.",
        "scope": "material"
      },
      {
        "label": "Melting point",
        "line": "The vendor gives 2230 °C and the Stanford Advanced Materials SDS gives 2235 °C for the melting point.",
        "scope": "material"
      },
      {
        "label": "Solubility",
        "line": "Insoluble in water and in several acids, per the vendor page and the BeanTown SDS.",
        "scope": "material"
      }
    ],
    "compare": "Within this profile, CaB6 has a density of 2.33 g/cm3 on the vendor pages and 2.3 g/cm3 on the SDS documents, and a melting point of 2230 °C (vendor) or 2235 °C (SDS). The sources read do not give CaB6 values for a direct ranking against other borides or against metals used for deoxidation, so no ranking is claimed here. No copper deoxidation test was read.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Melting point",
        "benchmark": "melting_point",
        "scope": "material"
      },
      {
        "label": "Oxidation start in air",
        "benchmark": "oxidation_onset_temp",
        "scope": "material"
      }
    ],
    "handling": [
      "Keep the powder sealed in a dry, cool, well-ventilated place away from moisture and oxidising agents (Stanford Advanced Materials SDS).",
      "Wear a dust respirator, rubber gloves and eye protection when handling it (Stanford Advanced Materials SDS).",
      "Above about 1273 K in air the powder oxidises (Matsushita and Komarneni 1999)."
    ],
    "good_for": [
      "Deoxidising copper melts, as the vendor describes (vendor page, no test result given).",
      "Adding boron to refractories as a dolomite additive (vendor)."
    ],
    "watch_out": [
      "Oxidation in air from 1273 K for a hot-pressed sintered body (Matsushita and Komarneni 1999).",
      "Irritation hazards H315, H319 and H335 on both supplier safety data sheets.",
      "Melting point conflicts between sources: 2200 °C and 2230 °C on one vendor page, 2235 °C on the SDS, and Undetermined on another SDS."
    ],
    "verdict": "CaB6 is a dense, high-melting boride powder sold for copper deoxidation, refractory additives and neutron shielding. The sources read support its melting point and density, and they show oxidation in air from 1273 K. Hardness, conductivity and space test data are missing from the sources read.",
    "recipe": {
      "line": "CaB6 is calcium hexaboride: one calcium atom for every six boron atoms in a cubic framework (space group Pm-3m). The boron atoms form octahedral cages around the centre of the cube, and the calcium sits at the cube corners (AFLOW prototype; Lee and Wang 2005).",
      "parts": [
        {
          "name": "Calcium",
          "symbol": "Ca",
          "role": "Sits at the cube corners of the unit cell and sets the cubic lattice with the boron framework. The vendor uses calcium as the metal in the boride."
        },
        {
          "name": "Boron",
          "symbol": "B",
          "role": "Forms B6 octahedra that give the boride its hardness and high melting point. Boron is also the part that stays dissolved in copper when CaB6 is used as a deoxidiser (vendor description)."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "Both supplier safety data sheets classify the powder as an irritant. Neither gives toxicology values.",
        "points": [
          {
            "label": "Skin and eyes",
            "line": "Causes skin irritation (H315) and serious eye irritation (H319), per the Stanford Advanced Materials SDS. The BeanTown SDS gives the same skin and eye hazards."
          },
          {
            "label": "Dust",
            "line": "May cause respiratory irritation (H335). Avoid breathing the dust, and use a dust respirator, gloves and eye protection."
          },
          {
            "label": "In a fire",
            "line": "The SDS lists borane and boron oxides and calcium oxide as decomposition products."
          }
        ],
        "level": 0,
        "verdict": "Irritant: H315, H319 and H335"
      },
      {
        "title": "If the powder is heated in air",
        "lead": "These results come from one 1999 abstract for a hot-pressed sintered body, not from field incidents.",
        "points": [
          {
            "label": "Oxidation start",
            "line": "Oxidation of hot-pressed CaB6 starts at 1273 K, and weight gain rises as the oxidation temperature goes up (Matsushita and Komarneni 1999)."
          },
          {
            "label": "Oxidising agents",
            "line": "The SDS says the powder reacts with oxidising agents, so keep it away from them."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Storage",
            "line": "Store the powder sealed in a dry, cool place. Long exposure to air can cause moisture agglomeration (vendor)."
          },
          {
            "label": "Spills",
            "line": "Vacuum spills with a HEPA filter and avoid raising dust (Stanford Advanced Materials SDS)."
          }
        ]
      }
    ]
  },
  "updated": "2026-11-01",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 13,
    "unreachable": 3,
    "caveats": 4,
    "note": "Written on 2026-11-01 from the Heeger Materials and FUSnano product pages, the Stanford Advanced Materials and BeanTown Chemical safety data sheets, the Molekula specification, USGS MCS 2026 boron, Matsushita and Komarneni (1999) abstract, Lee and Wang (2005) LBNL paper (saved PDF), and the AFLOW prototype page. Unreachable: PubChem (browser check), the 3M datasheet (403), the 2019 high-pressure CaB6 page (404)."
  },
  "sources": {
    "heeger-cab6": {
      "title": "Heeger Materials, Calcium Hexaboride (CaB6) Powder product page (reference HMBP-1321)",
      "url": "https://heegermaterials.com/boride-powders/1321-calcium-hexaboride-cab6-powder.html",
      "kind": "web",
      "license": "vendor web page, cited not reproduced"
    },
    "fusnano-cab6": {
      "title": "FUSnano, Calcium Hexaboride Powder product page",
      "url": "https://www.fusnano.com/boride/calcium-hexaboride-powder.html",
      "kind": "web",
      "license": "vendor web page, cited not reproduced"
    },
    "samaterials-sds-cab6": {
      "title": "Stanford Advanced Materials, Safety Data Sheet, Calcium Boride (CaB6)",
      "url": "https://samaterials.com/tds/sc/1735206667-BR0228.pdf",
      "kind": "datasheet",
      "license": "supplier SDS, cited not reproduced"
    },
    "beantown-sds-cab6": {
      "title": "BeanTown Chemical, Safety Data Sheet, Calcium hexaboride (article 216185), printed 07/09/2024",
      "url": "https://s3.amazonaws.com/beantown/216185.pdf",
      "kind": "datasheet",
      "license": "supplier SDS, cited not reproduced"
    },
    "molekula-spec-cab6": {
      "title": "Molekula Ltd, Technical Data Sheet, Calcium hexaboride (product 90027985)",
      "url": "https://molekula.com/specification/90027985.pdf",
      "kind": "datasheet",
      "license": "supplier specification, cited not reproduced"
    },
    "usgs-mcs2026-boron": {
      "title": "USGS Mineral Commodity Summaries 2026, Boron",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-boron.pdf",
      "kind": "report",
      "license": "US government work, public domain"
    },
    "matsushita-1999": {
      "title": "Matsushita J and Komarneni S, High temperature oxidation behavior of CaB6 sintered body, Journal of Materials Science 34(13), 3043-3046 (1999)",
      "url": "https://pure.psu.edu/en/publications/high-temperature-oxidation-behavior-of-cabsub6sub-sintered-body/",
      "kind": "paper",
      "license": "research-output record (abstract read)"
    },
    "lee-wang-2005": {
      "title": "Lee B and Wang L-W, Electronic Structure of Calcium Hexaborides (Lawrence Berkeley National Laboratory, 2005), eScholarship item 0370311w",
      "url": "https://escholarship.org/content/qt0370311w/qt0370311w.pdf",
      "kind": "paper",
      "license": "open repository (eScholarship)"
    },
    "aflow-cab6": {
      "title": "AFLOW Encyclopedia of Crystallographic Prototypes, A6B_cP7_221_e_b-001 (CaB6, ICSD 26753)",
      "url": "https://aflow.org/p/A6B_cP7_221_e_b-001",
      "kind": "database",
      "license": "AFLOW public database"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/calcium-hexaboride/"
}