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.
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
  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'
  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
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
    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)
  - benchmark: density
    label: Relative density, CaB6 powder (FUSnano)
    value: 2.33
    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)
  - benchmark: density
    label: Density at 20 °C, calcium boride (BeanTown SDS)
    value: 2.3
    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
  - benchmark: density
    label: Density, calcium boride (Stanford Advanced Materials SDS)
    value: 2.3
    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
  - benchmark: melting_point
    label: Melting point, CaB6 powder (Heeger Materials, More info text)
    value: 2230
    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)
  - benchmark: melting_point
    label: Melting point, CaB6 powder (Heeger Materials, bulleted list)
    value: 2200
    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)
  - benchmark: melting_point
    label: Melting point, CaB6 powder (FUSnano)
    value: 2230
    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)
  - benchmark: melting_point
    label: Melting point, calcium boride (Stanford Advanced Materials SDS)
    value: 2235
    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
  - benchmark: molar_mass
    label: Molecular weight, CaB6
    value: 104.94
    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)
  - benchmark: molar_mass
    label: Molecular weight, calcium boride (Stanford Advanced Materials SDS)
    value: 104.94
    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
  - benchmark: oxidation_onset_temp
    label: Oxidation start temperature, hot-pressed CaB6 sintered body
    value: 1273
    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
  - benchmark: purity
    label: Purity, CaB6 powder grade (Heeger Materials, vendor grade)
    value: 99.9
    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)
  - 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)
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.
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
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).'
story:
  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
      level: 0
      verdict: 'Irritant: H315, H319 and H335'
      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.
    - 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).
  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.
    - 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.
    - label: Melting point
      line: The vendor gives 2230 °C and the Stanford Advanced Materials SDS gives 2235 °C for the melting point.
    - label: Solubility
      line: Insoluble in water and in several acids, per the vendor page and the BeanTown SDS.
  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
    - label: Melting point
      benchmark: melting_point
    - label: Oxidation start in air
      benchmark: oxidation_onset_temp
  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.