spore: profile
id: chromium-carbide
spore_version: 0.2
family: carbide-nitride-boride-ceramics
name: Chromium carbide (Cr3C2)
abbreviation: Cr3C2
role: hard grey-black carbide powder for thermal-spray wear coatings, cutting tools and wear parts
category: ceramics
type: carbides
summary: |
  Chromium carbide (Cr3C2) is a hard, grey-black ceramic powder with an orthorhombic crystal structure. Stanford Advanced Materials gives a melting point of 1890 °C and a microhardness of 2280 kg/mm2 for its Cr3C2 powder, with no test method stated. Its 2012 safety data sheet gives a specific gravity of 6.68 gm/cc and a melting point of 1980.0 °C, so the two supplier melting values disagree. A 2022 first-principles study calculates a Young's modulus of 423.7 GPa and a theoretical hardness of 18.2 GPa for Cr3C2; these are calculated values, not measurements.
best_for: Hard wear-resistant coatings and tool or mould parts, where the powder is used for thermal spray (the supplier FAQ lists thermal spray coatings for wear protection)
weakest_at: 'Oxidation at high temperature: the sources read make only a general claim and give no oxidation onset, and the supplier SDS warns that moisture releases methane'
identity:
  formula: Cr3C2
  cas: 12012-35-0
  crystal_system: orthorhombic
  space_group: Pnma
  source: paper
  where: Introduction (Cr3C2 listed as Pnma among the binary chromium carbides); Section 2, Table 2 text 'For orthorhombic system (Cr7C3, Cr3C2)'. CAS printed on the supplier product page (sam-product) and SDS (sam-msds).
tags:
  environments: []
  stresses:
    - extreme-heat
  applications:
    - mechanisms
    - structures
properties:
  - benchmark: density
    label: Specific gravity printed in the supplier SDS
    value: 6.68
    unit: gm/cc
    scope: material
    conditions:
      basis: printed as Specific Gravity (water=1); no temperature, powder form or test method printed
      unit_in_source: gm/cc
    method: Manufacturer SDS value (Stanford Advanced Materials, version 2.0, revision 5 September 2012)
    status: ground
    source: sam-msds
    where: Section III, Specific Gravity (water=1) row
  - benchmark: density
    label: Density printed on a second supplier page
    value: 6.68
    unit: g/cm3
    scope: material
    conditions:
      basis: printed as Density in the Specifications section; not labelled true or bulk; no temperature or test method printed
    method: Supplier specification value
    status: ground
    source: sputter-cr3c2
    where: Specifications section, Density row
  - benchmark: melting_point
    value: 1890
    unit: °C
    scope: material
    conditions:
      basis: stated by the supplier with no test method; the description paragraph on the same page also gives 1890°C
    method: Supplier specification value
    status: ground
    source: sam-product
    where: Specification section, Melting point row; Description paragraph
  - benchmark: melting_point
    label: Melting point, 2012 supplier SDS (conflicts with the product page)
    value: 1980
    unit: °C
    scope: material
    conditions:
      basis: 'printed as Melting Point: 1980.0 C in the SDS physical characteristics; no test method'
    method: Manufacturer SDS value
    status: ground
    note: This value disagrees with the 1890 °C product-page value. Both are kept side by side; neither is backed by a measurement method in the sources read.
    source: sam-msds
    where: Section III, Melting Point row
  - benchmark: boiling_point
    value: 3800
    unit: °C
    scope: material
    conditions:
      basis: 'printed as Boiling Point: 3800.0 C in the SDS physical characteristics; no pressure or method printed'
    method: Manufacturer SDS value
    status: ground
    note: Not checked against any other source read in this run; kept only as printed.
    source: sam-msds
    where: Section III, Boiling Point row
  - benchmark: vickers_hardness
    label: Microhardness, supplier specification (test not stated)
    value: 2280
    unit: kg/mm2
    scope: material
    conditions:
      basis: printed as Microhardness in the Specification section; no load or test method stated
    method: Supplier specification value
    status: ground
    source: sam-product
    where: Specification section, Microhardness row
  - benchmark: theoretical_hardness
    label: Theoretical hardness, first-principles, zero pressure
    value: 18.2
    unit: GPa
    scope: material
    conditions:
      basis: calculated at zero applied pressure; the table column is headed H Gao
      pressure: 0 GPa
    method: Calculated in a first-principles study (CASTEP, density functional theory); a computed value, not a measurement
    status: calculated
    source: paper
    where: Section 3 text ('The theoretical hardness of Cr7C3, Cr3C2 and Cr23C6 was found to be 13.5, 18.2 and 10.1 GPa'); Table 4
  - benchmark: vickers_hardness
    label: Vickers hardness range for Cr3C2 quoted from earlier measurements
    value: 15.1
    value_high: 18.9
    bound: range
    unit: GPa
    scope: material
    conditions:
      basis: range across earlier studies quoted by the paper, which says reported values differ with sample preparation and measurement protocol; load not given
    method: Range quoted in the paper from other research groups
    status: ground
    source: paper
    where: Introduction, paragraph 2 (Hν (Cr3C2) = 15.1–18.9 GPa, with cited references)
  - benchmark: bulk_modulus
    value: 314.7
    unit: GPa
    scope: material
    conditions:
      basis: zero pressure; Voigt-Reuss-Hill average of calculated elastic constants
    method: Calculated in a first-principles study (CASTEP, density functional theory)
    status: calculated
    source: paper
    where: Table 2, Cr3C2 row, B/GPa column
  - benchmark: shear_modulus
    value: 166.1
    unit: GPa
    scope: material
    conditions:
      basis: zero pressure; Voigt-Reuss-Hill average of calculated elastic constants
    method: Calculated in a first-principles study (CASTEP, density functional theory)
    status: calculated
    source: paper
    where: Table 2, Cr3C2 row, G/GPa column
  - benchmark: elastic_modulus
    label: Young's modulus, calculated
    value: 423.7
    unit: GPa
    scope: material
    conditions:
      basis: zero pressure; Voigt-Reuss-Hill average of calculated elastic constants
    method: Calculated in a first-principles study (CASTEP, density functional theory)
    status: calculated
    source: paper
    where: Table 2, Cr3C2 row, E/GPa column
  - benchmark: poissons_ratio
    value: 0.28
    unit: '-'
    scope: material
    conditions:
      basis: zero pressure; calculated from the Voigt-Reuss-Hill averages
    method: Calculated in a first-principles study (CASTEP, density functional theory)
    status: calculated
    source: paper
    where: Table 2, Cr3C2 row, v column
  - benchmark: lattice_parameter_a
    label: Lattice parameter a, calculated at zero pressure
    value: 5.48
    unit: Å
    scope: material
    conditions:
      basis: zero pressure, orthorhombic cell
    method: Calculated in a first-principles study; the table lists experimental values beside it, which are not used here
    status: calculated
    source: paper
    where: Table 1, Cr3C2 row, a column
  - benchmark: lattice_parameter_b
    label: Lattice parameter b, calculated at zero pressure
    value: 2.79
    unit: Å
    scope: material
    conditions:
      basis: zero pressure, orthorhombic cell
    method: Calculated in a first-principles study
    status: calculated
    source: paper
    where: Table 1, Cr3C2 row, b column
  - benchmark: lattice_parameter_c
    label: Lattice parameter c, calculated at zero pressure
    value: 11.47
    unit: Å
    scope: material
    conditions:
      basis: zero pressure, orthorhombic cell
    method: Calculated in a first-principles study
    status: calculated
    source: paper
    where: Table 1, Cr3C2 row, c column
corrosion:
  - environment: Moisture and water contact
    headline: The supplier safety data sheet says Cr3C2 reacts with moisture to form methane gas.
    effect: The 2012 SDS states that the powder reacts with moisture to form methane gas, and it lists moisture among the materials to avoid. The sheet gives no reaction rate, temperature or test.
    rating: moderate
    conditions:
      basis: supplier statement, no test conditions
    source: sam-msds
    where: Section V (Incompatibility) and Section VII (handling paragraph)
  - environment: Strong oxidizing agents, acids and bases
    headline: The supplier SDS lists strong oxidizing agents, acids and bases as materials to avoid.
    effect: The SDS gives this as an incompatibility statement without concentrations, times or test results.
    rating: low
    conditions:
      basis: incompatibility list, no test data
    source: sam-msds
    where: Section V (Incompatibility - materials to avoid)
  - environment: High-temperature air
    headline: The 2022 paper describes outstanding oxidation resistance at high temperature, without a figure.
    effect: The paper's introduction describes 'outstanding oxidation resistance under a high temperature environment' for the binary chromium carbides. It gives no oxidation onset temperature, exposure time or test method, so this is a general statement only.
    rating: unknown
    conditions:
      basis: general statement in the introduction; no test
    source: paper
    where: Introduction, paragraph 1
risks:
  hazards:
    - text: PubChem's hazards summary for the chromium carbide record reads 'May be harmful after ingestion, inhalation, or skin contact; May damage eyes'.
      ghs: []
      source: pubchem-cr3c2
      where: Safety and Hazards, Hazards Identification, Hazards Summary (CID 3650773)
    - text: The supplier product page lists the hazard statement 'Flammable solid' with the signal word 'Warning'.
      ghs: []
      source: sam-product
      where: Safety information block
  failure_risks:
    - mode: Methane release on contact with moisture
      trigger: Contact with moisture or water
      consequence: The SDS says the powder reacts with moisture to form methane gas.
      severity: moderate
      source: sam-msds
      where: Section V (Hazardous decomposition or byproducts) and Section VII
  side_effects:
    - text: The SDS says 'Chromium carbide may emit toxic fumes if involved in a fire'.
      affects: Firefighters and people near a fire
      source: sam-msds
      where: Section IV, Unusual fire and explosion hazards
    - text: PubChem notes that trivalent chromium 'may be oxidized to hexavalent chromium, a known carcinogen'.
      affects: Workers handling heated or oxidized material
      source: pubchem-cr3c2
      where: Toxicity, Health Effects
  handling:
    - text: Store in a cool, dry area, in a tightly sealed container, under an inert gas such as argon, as the SDS directs.
      source: sam-msds
      where: Section VII and Section VIII (Other)
    - text: Keep the powder away from moisture, strong oxidizing agents, acids and bases, which the SDS lists as materials to avoid.
      source: sam-msds
      where: Section V
    - text: Take care not to raise dust, and use a NIOSH-approved dust respirator where the SDS requires it.
      source: sam-msds
      where: Section VII and Section VIII (Respiratory)
    - text: PubChem prints the PEL and the TLV as '0.5 [mg/m3], as Cr'. The SDS prints '0.5 mg/m3' and '1 mg/m3' under the headings ACGIH-TLV and OSHA PEL, so the two sources do not agree on the PEL.
      source: pubchem-cr3c2
      where: Exposure Control and Personal Protection (PEL and TLV); the SDS figures are in Section II
uses:
  - application: mechanisms
    device: Cutting tools, drilling bits and wear parts
    example: The supplier says Chromium Carbide Powder is commonly used in the production of cutting tools, drilling bits, wear-resistant parts, molds, and coatings for turbine components.
    source: sam-product
    where: Chromium Carbide Powder Applications section
  - application: structures
    device: Coatings for turbine components and thermal spray
    example: The same supplier page lists coatings for turbine components, and its FAQ names thermal spray coatings for wear protection.
    source: sam-product
    where: Chromium Carbide Powder Applications section; FAQs
  - application: mechanisms
    device: Grain refinement agent in cemented carbide
    example: The 2022 paper says chromium carbides can be used as grain refinement agents in cemented carbide and other wear-resistance components.
    source: paper
    where: Introduction, paragraph 1
supply:
  - subject: Chromium (the metal in Cr3C2; the carbon supply is not covered by any source read in this run)
    producers:
      - country: South Africa
        share_percent: 45.1
        year: 2025
      - country: Turkey
        share_percent: 17.6
        year: 2025
      - country: Kazakhstan
        share_percent: 13.7
        year: 2025
      - country: India
        share_percent: 5.9
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals (the page lists Chromium, used in stainless steel)
        listed: true
    recycling: 'USGS: ''In 2025, recycled chromium (contained in reported stainless-steel scrap receipts) accounted for 21% of apparent consumption.'''
    substitutes:
      - 'USGS: ''Chromium has no substitute in stainless steel, the leading end use, or in superalloys, the major strategic end use.'''
    source: usgs-mcs2026-chromium
    where: 'World Mine Production and Reserves table, 2025e column (chromium content in thousand metric tons; world total 51,000 rounded; shares calculated by Space Mushroom against that total); Recycling; Substitutes. Critical list: USGS 2025 critical minerals page (usgs-crit2025).'
gaps:
  - Oxidation onset in air for dense Cr3C2 was not found in any source read in this run. A search snippet for the powder was not opened and is not used.
  - No thermal conductivity, coefficient of thermal expansion, specific heat or band gap for Cr3C2 was found in any source read.
  - No bulk or tap density was found in a fetched source. The American Elements pages were blocked by a browser check, and search snippets are not used.
  - The PubChem web page was blocked by a browser check. The PubChem REST record was read instead; it gives a hazards summary and exposure limits but no GHS hazard statements, so the GHS field is empty.
  - No UNS, EN, ASTM or other designation for Cr3C2 was printed in a source read in this run. Identity uses the CAS number printed on the supplier product page and SDS.
  - Crystal structure is printed as Rhombohedral on two supplier pages. The paper gives orthorhombic, space group Pnma, and that is what identity records.
  - 'Melting point conflicts: the product page gives 1890 °C and the 2012 SDS gives 1980.0 °C. Wikipedia gives a different melting value, which is not used. Wikipedia is cited for production routes only.'
  - The 2012 SDS boiling point is not confirmed by any other source read in this run.
  - 'Exposure limits differ between PubChem and the SDS, as shown in risks.handling. Carcinogen labels also differ: the SDS calls chromium a confirmed human carcinogen, while PubChem gives a carcinogen classification (see the PubChem record).'
  - Atomic weights of chromium and carbon were not read in a fetched page, so story.recipe.parts has no atomic_weight.
  - The paper's other quoted Vickers hardness ranges for Cr3C2 are not recorded as separate rows; the paper gives them without measurement details.
  - 'Property names not in spores/property-canon.yaml: vickers_hardness (used for microhardness and the quoted range), theoretical_hardness, lattice_parameter_a, lattice_parameter_b and lattice_parameter_c.'
  - The paper's elastic, bulk, shear and lattice values are first-principles results at zero pressure, marked status calculated. They are not measured values.
  - Supply covers chromium only. The EU critical raw materials list was not opened in this run, so no EU listing is recorded.
  - No space, vacuum, radiation or atomic-oxygen results for Cr3C2 were found.
  - The IPEN paper on attrition-milled Cr3C2 refused the connection and was not read.
  - No media images were added.
sources:
  sam-product:
    title: Chromium Carbide (Cr3C2) Powder product page, Stanford Advanced Materials (specification, description, applications, safety and FAQ sections)
    id: CAS 12012-35-0; catalog CR1314
    url: https://www.samaterials.com/chromium/1314-chromium-carbide-cr3c2-powder.html
    kind: web
    license: supplier page (cited, not reproduced)
  sam-msds:
    title: 'Material Safety Data Sheet: Chromium carbide, Cr3C2 (Stanford Advanced Materials, version 2.0, revision 5 September 2012), hosted by Sputter Targets'
    id: CAS 12012-35-0
    url: https://www.sputtertargets.net/Public/pdf/chromium-carbide-msds.pdf
    year: 2012
    kind: datasheet
    license: supplier document (cited, not reproduced)
  sputter-cr3c2:
    title: Chromium Carbide Powder product page, Sputter Targets (Cr3C2 specifications)
    url: https://www.sputtertargets.net/chromium-carbide-powder/
    kind: web
    license: supplier page (cited, not reproduced)
  paper:
    title: 'First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6: Electronic Structures, Mechanical Properties and Thermodynamic Properties under Pressure'
    id: doi:10.3390/ma15020558 (Materials 15(2), 558; PMC8779879)
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/
    year: 2022
    kind: paper
    license: open access (licence as listed by the journal; not checked in this run)
  usgs-mcs2026-chromium:
    title: Mineral Commodity Summaries 2026, Chromium
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-crit2025:
    title: About the 2025 List of Critical Minerals (USGS, final list of 60 minerals)
    id: Final 2025 List of Critical Minerals, November 2025
    url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
    year: 2025
    kind: web
    license: public domain (USGS)
  pubchem-cr3c2:
    title: 'PubChem compound record CID 3650773, chromium carbide (Cr3C2, CAS 12012-35-0): hazards summary, exposure limits, toxicity'
    id: CID 3650773
    url: https://pubchem.ncbi.nlm.nih.gov/compound/3650773
    year: 2026
    kind: database
    license: public domain (NCBI)
  wiki-cr3c2:
    title: Wikipedia, Chromium(II) carbide (composition and production routes only; numbers not used)
    url: https://en.wikipedia.org/wiki/Chromium(II)_carbide
    kind: web
    license: CC BY-SA
documents:
  - title: 'Material Safety Data Sheet: Chromium carbide, Cr3C2 (Stanford Advanced Materials, 2012)'
    type: sds
    url: https://www.sputtertargets.net/Public/pdf/chromium-carbide-msds.pdf
    year: 2012
  - title: Chromium Carbide (Cr3C2) Powder product page (Stanford Advanced Materials)
    type: datasheet
    url: https://www.samaterials.com/chromium/1314-chromium-carbide-cr3c2-powder.html
    year: 2026
  - title: First Principles Investigation of Binary Chromium Carbides Cr7C3, Cr3C2 and Cr23C6 (Materials 15(2), 558, 2022)
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC8779879/
    year: 2022
  - title: Mineral Commodity Summaries 2026, Chromium
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-chromium.pdf
    year: 2026
  - title: 'PubChem: chromium carbide (CID 3650773), hazards and toxicity sections'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/3650773
    year: 2026
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 15
  unreachable: 2
  caveats: 3
  note: 'Written by an AI assistant on 2026-11-01 from pages read in this run. Unreachable as web pages: the American Elements pages (browser check) and the PubChem web page (browser check; the PubChem REST record was read instead). Calculated values are first-principles results, not measurements.'
story:
  recipe:
    line: 'Chromium carbide (Cr3C2) is a binary compound of chromium and carbon with an orthorhombic crystal structure. The 2022 paper lists Cr3C2 among the stable binary chromium carbides at ambient pressure, alongside the other two carbides it studies. Wikipedia describes two production routes: mechanical alloying of chromium and graphite followed by hot isostatic pressing under argon, and a self-propagating exothermic reaction that uses chromium oxide, aluminum and graphite.'
    parts:
      - name: Chromium
        symbol: Cr
        role: The metal in the compound. The paper says metallic bonding runs between neighbouring chromium atoms, and the chromium-carbon bonds give the hardness it reports.
      - name: Carbon
        symbol: C
        role: Bonds covalently to chromium in the paper's bonding analysis; the Cr-C bond strength is the basis of its theoretical hardness.
  risk_groups:
    - title: For people
      level: 0
      verdict: Harmful by inhalation or ingestion, per PubChem
      lead: PubChem's hazards summary says the material may be harmful after ingestion, inhalation or skin contact, and may damage eyes. The supplier SDS calls chromium a confirmed human carcinogen. These are supplier and database summaries, not incident records.
      points:
        - label: Summary
          line: PubChem's hazards summary reads 'May be harmful after ingestion, inhalation, or skin contact; May damage eyes'.
        - label: Carcinogen labels differ
          line: The 2012 SDS calls chromium a 'Confirmed human carcinogen'. PubChem's carcinogen classification reads '3, not classifiable as to its carcinogenicity to humans.'
        - label: Flammability
          line: The supplier product page lists the hazard statement 'Flammable solid' with the signal word 'Warning'.
    - title: If the powder is heated or burns
      lead: These statements come from supplier sheets and database summaries, not from field incidents.
      points:
        - label: Fire
          line: The SDS says the material 'may emit toxic fumes if involved in a fire', and it calls for full face, self-contained breathing apparatus for firefighters.
        - label: Oxidized chromium
          line: PubChem says trivalent chromium 'may be oxidized to hexavalent chromium, a known carcinogen'.
    - title: Handling and storage
      points:
        - label: Moisture
          line: The SDS says the powder 'reacts with moisture to form methane gas'. It asks for storage in a cool, dry area in a tightly sealed container, under an inert gas such as argon.
        - label: Exposure limits
          line: PubChem prints '0.5 [mg/m3], as Cr' for both the PEL and the TLV. The SDS prints '0.5 mg/m3' and '1 mg/m3' under the headings ACGIH-TLV and OSHA PEL.
  why: Chromium carbide (Cr3C2) is a hard ceramic powder made of chromium and carbon. Its supplier calls it a hard, durable coating material for protection against wear, corrosion and high temperatures, and lists it for cutting tools, drilling bits, wear-resistant parts and molds. It is supplied as a grey-black powder, and the supplier names thermal spray as a use. Its hardness and stiffness are the main reasons it is used. Its melting values disagree between two supplier sheets, and no measured high-temperature oxidation figure was found in the sources read.
  uses:
    - where: Cutting tools, drilling bits and molds
      line: The supplier says the powder is commonly used in cutting tools, drilling bits, wear-resistant parts and molds.
    - where: Turbine coatings and thermal spray
      line: The supplier lists coatings for turbine components, and its FAQ names thermal spray coatings for wear protection. These are supplier statements; no field test was found.
    - where: Grain refiner in cemented carbide
      line: The 2022 paper says chromium carbides can be used as grain refinement agents in cemented carbide and other wear-resistance components.
  can_do:
    - label: Hardness
      benchmark: vickers_hardness
      value: 2280 kg/mm2
      line: The supplier gives a microhardness of 2280 kg/mm2 with no test method stated. The paper quotes a Vickers hardness of 15.1 to 18.9 GPa for Cr3C2 from earlier studies, and calculates a theoretical hardness of 18.2 GPa.
    - label: Stiffness
      benchmark: elastic_modulus
      value: 423.7 GPa
      line: The 2022 paper calculates a Young's modulus of 423.7 GPa and a Poisson's ratio of 0.28 at zero pressure. These are calculated values, not measurements.
    - label: Density
      benchmark: density
      value: 6.68 g/cm3
      line: 'Two suppliers print a density of 6.68: one in gm/cc in a 2012 safety data sheet, and one in g/cm3 on a product page.'
    - label: Melting point
      benchmark: melting_point
      value: 1890 °C
      line: The supplier product page gives a melting point of 1890 °C, and its 2012 safety data sheet gives 1980.0 °C. The two supplier values differ, and neither prints a method.
  compare: 'Chromium carbide sits among the hard refractory carbides. Its supplier microhardness of 2280 kg/mm2 and its calculated theoretical hardness of 18.2 GPa are both high. The sources read here give no direct side-by-side comparison with the other carbides in this collection. The two supplier melting values, 1890 °C and 1980.0 °C, disagree and are shown side by side. Oxidation in air is not quantified in the sources read. The hardness values are not directly comparable: the supplier figure has no test method, and the paper''s figures are calculated or quoted from other studies.'
  compare_rows:
    - label: Microhardness (supplier)
      benchmark: vickers_hardness
    - label: Melting point (supplier)
      benchmark: melting_point
    - label: Young's modulus (calculated)
      benchmark: elastic_modulus
  handling:
    - Store in a cool, dry area, in a tightly sealed container, under an inert gas such as argon, as the SDS directs.
    - Keep the powder away from moisture, strong oxidizing agents, acids and bases, which the SDS lists as materials to avoid.
    - Take care not to raise dust, and use a NIOSH-approved dust respirator where the SDS requires it.
    - Check the supplier's current SDS for your grade, because the 2012 SDS and the product pages disagree on melting point and on exposure limits.
  good_for:
    - Hard wear parts. The supplier says it is used in cutting tools, drilling bits, wear-resistant parts and molds.
    - Thermal spray coatings. The supplier FAQ lists thermal spray coatings for wear protection.
    - Stiff hard coatings in design studies. The paper's calculated Young's modulus of 423.7 GPa is a theoretical value.
  watch_out:
    - Moisture reaction. The SDS says the powder reacts with moisture to form methane gas.
    - Conflicting melting values. The product page gives 1890 °C and the 2012 SDS gives 1980.0 °C.
    - Oxidation in air is not quantified. The paper says 'outstanding oxidation resistance under a high temperature environment' without a figure.
    - Crystal structure is printed two ways. Two supplier pages say Rhombohedral; the paper gives orthorhombic, space group Pnma.
  verdict: Chromium carbide is a hard wear-resistant powder for coatings and tool parts. Its hardness data are stronger than its melting and oxidation data, and the supplier figures should be checked against a current SDS before use.