Lutetium Lu

spore: profile
id: lutetium
spore_version: 0.2
family: rare-earth-metals
name: Lutetium
abbreviation: Lu
role: scintillator component (LYSO, LuAG) and catalyst metal
category: metals
type: heavy-metals
summary: |
  Lutetium is the rare-earth element Lu (atomic number 71). The metal is silvery, with a density of 9.842 g/cm3 at 20 degC and a melting point of 1663 degC (Goodfellow datasheet). It is one of the scarcer rare earths, with an average crustal abundance of 0.8 ppm (USGS). Its main use is in scintillator crystals: the cerium-doped LYSO used in PET detectors has a density of 7.2 g/cm3 and a decay time of 50 ns (BNC datasheet). The metal is a flammable solid. Its supplier SDS gives a flammable-solid hazard, and it releases flammable gas on contact with water, so it needs dry, inert handling.
best_for: Lutetium-containing scintillators for PET detectors, where high density and a 50 ns decay matter (BNC LYSO datasheet)
weakest_at: Flammable as chips or powder, and it releases flammable gas on contact with water (PubChem GHS; ChemicalBook SDS, H260)
identity:
  formula: Lu (element, atomic number 71); unalloyed metal, sold as 99 % (2N) disc, 99.9 % (3N) pellets and 99.9 % chips
  cas: 7439-94-3
  source: nist-atomic-weights
  where: Lutetium entry, atomic number 71 and standard atomic weight 174.9668(1); CAS 7439-94-3 printed on the Goodfellow disc page; PubChem CID 23929
tags:
  applications:
    - optics-and-cameras
properties:
  - benchmark: density
    label: Density, lutetium disc (99 % purity)
    value: 9.842
    unit: g/cm3
    scope: material
    conditions:
      temperature: 20 °C
      purity: 99% (2N)
      form: disc
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Physical Properties table, row Density (9.842 g cm-3 at 20 °C)
  - benchmark: density
    label: Density, lutetium pellets (99.9 % purity)
    value: 9.842
    unit: g/cm3
    scope: material
    conditions:
      temperature: 20 °C
      purity: 99.9% (3N)
      form: pellets
    method: Value printed in a second supplier datasheet, for the pellet product
    status: ground
    source: goodfellow-lu-pellets
    where: Physical properties table, row Density (9.842 g cm-3 at 20 °C)
  - benchmark: melting_point
    label: Melting point, lutetium disc
    value: 1663
    unit: °C
    scope: material
    conditions:
      pressure: not stated
    method: Value printed in a supplier product datasheet
    status: ground
    note: Wikipedia and American Elements print about 1652 °C. The supplier value is used here, and the difference is not resolved.
    source: goodfellow-lu-disc
    where: Thermal Properties table, row Melting point (1663 °C, no conditions stated)
  - benchmark: melting_point
    label: Melting point, lutetium pellets
    value: 1663
    unit: °C
    scope: material
    conditions:
      pressure: not stated
    method: Value printed in a second supplier datasheet, for the pellet product
    status: ground
    source: goodfellow-lu-pellets
    where: Thermal Properties table, row Melting point (1663 °C, no conditions stated)
  - benchmark: boiling_point
    label: Boiling point, lutetium
    value: 3395
    unit: °C
    scope: material
    conditions:
      pressure: not stated
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Physical Properties table, row Boiling point (3395 °C, none stated)
  - benchmark: specific_heat
    label: Specific heat capacity, lutetium disc
    value: 155
    unit: J/(kg·K)
    scope: material
    conditions:
      temperature: 25 °C
      purity: 99% (2N)
      unit_in_source: J K-1 kg-1
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Thermal Properties table, row Specific heat (155 J K-1 kg-1 at 25 °C)
  - benchmark: thermal_conductivity
    label: Thermal conductivity, lutetium disc
    value: 16.4
    unit: W/(m·K)
    scope: material
    conditions:
      temperature: 0 to 100 °C
      purity: 99% (2N)
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Thermal Properties table, row Thermal conductivity (16.4 W m-1 K-1 at 0-100 °C)
  - benchmark: cte
    label: Coefficient of thermal expansion, lutetium disc
    value: 12.5
    unit: ppm/K
    scope: material
    conditions:
      temperature: 0 to 400 °C
      purity: 99% (2N)
      unit_in_source: 12.5 × 10-6 K-1
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Thermal Properties table, row Coefficient of thermal expansion (12.5 × 10-6 K-1 at 0-400 °C)
  - benchmark: elastic_modulus
    label: Tensile modulus, polycrystalline lutetium
    value: 84
    unit: GPa
    scope: material
    conditions:
      material_condition: polycrystalline
      temperature: not stated
    method: Value printed in a supplier product datasheet; the page gives no separate Young's modulus
    status: ground
    source: goodfellow-lu-disc
    where: Mechanical Properties table, row Tensile modulus (84 GPa)
  - benchmark: bulk_modulus
    label: Bulk modulus, polycrystalline lutetium
    value: 42
    unit: GPa
    scope: material
    conditions:
      material_condition: polycrystalline
      temperature: not stated
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Mechanical Properties table, row Bulk modulus (42 GPa)
  - benchmark: poisson_ratio
    label: Poisson's ratio, polycrystalline lutetium
    value: 0.223
    unit: '-'
    scope: material
    conditions:
      material_condition: polycrystalline
      temperature: not stated
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Mechanical Properties table, row Poisson's ratio (0.223)
  - benchmark: vickers_hardness
    label: Vickers hardness, polycrystalline lutetium
    value: 85
    unit: kgf/mm2
    scope: material
    conditions:
      material_condition: polycrystalline
      load: not stated
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Mechanical Properties table, row Hardness (Vickers) 85 kgf mm-2
  - benchmark: electrical_resistivity
    label: Electrical resistivity, lutetium
    value: 68
    unit: µΩ·cm
    scope: material
    conditions:
      temperature: 20 °C
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Electrical Properties table, row Electrical resistivity (68 µΩ cm at 20 °C)
  - benchmark: superconducting_critical_temperature
    label: Superconducting critical temperature, lutetium
    value: 0.1
    unit: K
    scope: material
    conditions:
      temperature_basis: not stated
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Electrical Properties table, row Superconductivity critical temperature (0.1 K, none stated)
  - benchmark: latent_heat_fusion
    label: Latent heat of fusion, lutetium
    value: 110
    unit: J/g
    scope: material
    conditions:
      pressure: not stated
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Thermal Properties table, row Latent heat of fusion (110 J g-1)
  - benchmark: latent_heat_vaporization
    label: Latent heat of evaporation, lutetium
    value: 2155
    unit: J/g
    scope: material
    conditions:
      pressure: not stated
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Thermal Properties table, row Latent heat of evaporation (2155 J g-1)
  - benchmark: temperature_coefficient_of_resistance
    label: Temperature coefficient of resistance, lutetium
    value: 0.0024
    unit: 1/K
    scope: material
    conditions:
      temperature: 0 to 100 °C
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-lu-disc
    where: Electrical Properties table, row Temperature coefficient (0.0024 K-1 at 0-100 °C)
  - benchmark: atomic_weight
    label: Standard atomic weight, lutetium
    value: 174.9668
    unit: u
    scope: material
    conditions:
      basis: NIST standard atomic weight; uncertainty (1) in the last digit
    method: Value printed in the NIST atomic-weight table
    status: ground
    source: nist-atomic-weights
    where: Lutetium (Lu) entry, standard atomic weight 174.9668(1)
  - benchmark: isotopic_abundance
    label: Natural abundance of Lu-176 (radioactive isotope)
    value: 0.02599
    unit: mole fraction
    scope: material
    conditions:
      isotope: Lu-176
      basis: natural isotopic composition as printed
    method: Value printed in the NIST isotopic-composition table, printed as 0.025 99(13)
    status: ground
    source: nist-atomic-weights
    where: Lutetium (Lu) entry, isotope 176 row, isotopic composition 0.025 99(13)
  - benchmark: crustal_abundance
    label: Average crustal abundance, lutetium
    value: 0.8
    unit: ppm
    scope: material
    conditions:
      basis: average crustal abundance of the element
    method: Value printed in the USGS table of crustal abundances of mineral commodities
    status: ground
    source: usgs-pp1802a
    where: Table A1, row Lutetium (Lu) 0.8
corrosion:
  - environment: Dry and moist air at room temperature
    headline: Lutetium tarnishes slowly in air, and the supplier element overview says it burns to the oxide when heated to about 150 °C.
    effect: The supplier overview says the metal will slowly tarnish in air and burns to form the oxide if heated about 150 °C. The SDS gives no air-sensitivity statement and no moisture-specific corrosion data, so the rate of tarnishing in moist air is not known from the sources read here.
    rating: moderate
    conditions:
      basis: general element overview on a supplier product page; no exposure time or humidity stated
    source: prochem-lu-chips
    where: Element overview section (separate from the product listing)
  - environment: Water and moisture
    headline: On contact with water, lutetium releases flammable gas that can ignite on its own.
    effect: 'The SDS classifies the metal under H260: in contact with water it releases flammable gases which may ignite spontaneously. It advises keeping the material away from any possible contact with water, because of violent reaction and possible flash fire, and protecting it from moisture. A reaction with water is a fire-and-gas hazard, not a slow corrosion.'
    rating: severe
    conditions:
      basis: GHS statements and precautionary statements in the SDS; no test data
    source: chemicalbook-lu-sds
    where: Hazard statement H260; precautionary statements P223 and P231+P232
risks:
  hazards:
    - text: PubChem records a GHS classification of H228 (flammable solid) for 88.2% of company reports, with signal word Danger. The ECHA notes state that it does not meet GHS hazard criteria for 7.8% (4 of 51) of reports.
      ghs:
        - H228
      source: pubchem-lu
      where: Safety and Hazards, GHS Classification (CID 23929)
    - text: 'Supplier product page (Goodfellow, lutetium disc): GHS02 pictogram labelled Flammable. No hazard statement text is printed on the page; the SDS is available on request.'
      ghs: []
      source: goodfellow-lu-disc
      where: Product header, GHS pictogram
    - text: 'Supplier SDS (ChemicalBook, CB2168799, revision 2026-08-29): Flammable solids, Category 1; signal word Danger; H228 Flammable solid; H260 In contact with water releases flammable gases which may ignite spontaneously.'
      ghs:
        - H228
        - H260
      source: chemicalbook-lu-sds
      where: Section 2 hazard statements; signal word
  failure_risks:
    - mode: Ignition of chips, fines or powder
      trigger: Heat, sparks or an open flame near the metal; the SDS also warns against dust formation
      consequence: The supplier SDS classifies the metal as a flammable solid (H228) and gives P210 and P241 for heat and explosion-proof equipment. Flammable solids can ignite on their own in the presence of air or heat.
      severity: high
      source: chemicalbook-lu-sds
      where: Hazard statements H228; precautionary statements P210 and P241
    - mode: Contact with water
      trigger: Water or moisture contacting the metal
      consequence: The SDS states that contact with water releases flammable gases which may ignite spontaneously (H260), and it warns of violent reaction and possible flash fire (P223).
      severity: high
      source: chemicalbook-lu-sds
      where: Hazard statement H260; precautionary statement P223
    - mode: Oxidation to the oxide when heated
      trigger: Heating in air to about 150 °C
      consequence: The metal burns to form lutetium oxide. The source gives no quantity or rate for the reaction.
      severity: moderate
      source: prochem-lu-chips
      where: Element overview section
  side_effects:
    - text: The SDS gives no data for hazardous decomposition products, so the composition of any smoke or fume from a fire is not known from the sources read here.
      affects: People near a fire, and anyone who needs to plan extinguishing
      source: chemicalbook-lu-sds
      where: Section 10 (Hazardous decomposition products, no data available)
  handling:
    - text: 'SDS precautions: handle under inert gas and protect from moisture (P231+P232); keep away from heat, sparks and open flames (P210); ground and bond the container and receiving equipment (P240); use explosion-proof equipment (P241); wear protective gloves, clothing and eye protection (P280).'
      source: chemicalbook-lu-sds
      where: Precautionary statements, Section 7
    - text: The SDS asks to avoid formation of dust and aerosols.
      source: chemicalbook-lu-sds
      where: Sections 6 and 7
    - text: The Goodfellow product page for the disc gives no storage conditions, and the product page refers to the SDS for handling.
      source: goodfellow-lu-disc
      where: Other details
  mitigations:
    - text: For a fire, the SDS lists dry chemical, carbon dioxide or alcohol-resistant foam as extinguishing media. Do not use water, because the metal reacts with water to release flammable gas.
      source: chemicalbook-lu-sds
      where: Section 5 (extinguishing media), with the H260 statement
uses:
  - application: optics-and-cameras
    device: PET scanner detector crystal (LYSO, a lutetium-yttrium silicate scintillator)
    example: The BNC LYSO datasheet gives a density of 7.2 g/cm3, a decay time of 50 ns, a light yield of 30 photons per keV, and a peak emission at 420 nm. The page gives the composition as Lu1.8Y0.2SiO5:Ce in the overview and as LSO (Lu1.8Y0.2SiO5:Ce) in the specifications table, which differ in the yttrium subscript; the page does not resolve this.
    source: bnc-lyso
    where: Datasheet title 'LYSO Scintillation Crystals for PET & Fast Timing', Overview and Specifications table
  - application: optics-and-cameras
    device: Medical imaging and electronics materials
    example: The USGS 2025 critical-minerals page describes lutetium as used for medical imaging, electronics and some cancer therapies.
    source: usgs-crit2025
    where: Entry for lutetium in the final 2025 List of Critical Minerals
supply:
  - subject: Lutetium
    abundance: 0.8 ppm average crustal abundance (USGS Professional Paper 1802-A, Table A1)
    producers:
      - country: China
        share_percent: 69.2
        year: 2025
      - country: United States
        share_percent: 13.1
        year: 2025
      - country: Australia
        share_percent: 7.4
        year: 2025
      - country: Burma
        share_percent: 5.6
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals (lutetium named as an individual rare earth)
        listed: true
    recycling: 'USGS: limited quantities of rare earths were recovered from batteries, permanent magnets and fluorescent lamps. No lutetium-specific recycling figure was found.'
    substitutes: []
    source: usgs-mcs2026-rare-earths
    where: World Mine Production and Reserves table, 2025 (all rare earths; China 270,000 t and world total 390,000 t, rounded; the shares in producers are calculated by Space Mushroom from those figures, with the United States 51,000 t, Australia 29,000 t and Burma 22,000 t). Recycling paragraph. The table covers all rare earths, not lutetium alone.
media: []
documents:
  - title: USGS Mineral Commodity Summaries 2026, Rare Earths
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf
    year: 2026
  - title: Goodfellow lutetium disc product page (physical, thermal, mechanical and electrical properties)
    type: datasheet
    url: https://www.goodfellow.com/uk/lutetium-disc-group
    year: 2026
  - title: Goodfellow lutetium pellets product page
    type: datasheet
    url: https://www.goodfellow.com/eu/lutetium-pellets-group
    year: 2026
  - title: 'PubChem: Lutetium (CID 23929), GHS classification summary'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/23929
    year: 2026
  - title: 'ChemicalBook: lutetium metal SDS (CB2168799, revision 2026-08-29)'
    type: sds
    url: https://www.chemicalbook.com/msds/lutetium.htm
    year: 2026
  - title: USGS Professional Paper 1802-A, Critical Mineral Resources of the United States (Table A1)
    type: report
    url: https://pubs.usgs.gov/pp/1802/a/pp1802a.pdf
    year: 2017
  - title: 'NIST Atomic Weights and Isotopic Compositions: Lutetium'
    type: database
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=Lu&all=all&ascii=html
    year: 2026
  - title: BNC LYSO Scintillators datasheet
    type: datasheet
    url: https://www.berkeleynucleonics.com/docs/bnc-scintiq-lyso-datasheet.html
    year: 2026
  - title: 'ProChem product page: lutetium chips (product 2383)'
    type: datasheet
    url: https://prochemonline.com/product/lutetiumchips-2383/
    year: 2026
  - title: 'USGS: About the 2025 List of Critical Minerals'
    type: report
    url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
    year: 2025
gaps:
  - No tensile strength, yield strength or elongation was found for lutetium in a source read in this run. The Goodfellow pages give only a tensile modulus.
  - No crystal structure or space group was taken from a source read in this run. Wikipedia gives hexagonal close-packed, but Wikipedia is used here for history and composition only.
  - No EU critical raw materials list page was opened, so the EU listing for lutetium is not stated. The USGS 2025 list entry is the only critical-list source.
  - No lutetium-specific production figure was found. The USGS rare-earth table covers all rare earths combined, so the producer shares are shares of all rare earths.
  - The LYSO value for light yield and the density used in the uses section come from one vendor datasheet. The EJNMMI Physics review table could not be opened, and the vendor page gives a yttrium subscript that conflicts with its own specifications table.
  - Corrosion data are thin. The only air-tarnishing statement comes from one supplier product page, and the SDS has no air or humidity data. Rate of tarnish in moist air is not known.
  - The supplier hazard classifications differ. A Fisher-type sheet lists Warning and flammable solid, and the ChemicalBook SDS lists Danger, so the current SDS of the supplier used should be checked. The Fisher SDS page could not be opened in this run.
  - 'The melting point differs between sources: 1663 °C (Goodfellow) against about 1652 °C (Wikipedia and American Elements). Only the Goodfellow value is entered.'
  - Benchmarks bulk_modulus, poisson_ratio, superconducting_critical_temperature, latent_heat_fusion, latent_heat_vaporization, temperature_coefficient_of_resistance, isotopic_abundance and crustal_abundance may not be in the canonical property file; they are short snake_case names as the brief allows.
  - No media (crystal structure or photograph) was added; no suitable image was checked for licence in this run.
  - No designations (UNS, EN or similar) were added, because they apply to alloys and grades, not to the element.
  - Lutetium-177 cancer therapy is a radionuclide use, not a use of the metal, and no source read here supports a figure for it.
sources:
  goodfellow-lu-disc:
    title: 'Goodfellow: Lutetium disc, physical, thermal, mechanical and electrical properties (UK page)'
    id: Goodfellow product group lutetium disc, CAS 7439-94-3, 99% (2N)
    url: https://www.goodfellow.com/uk/lutetium-disc-group
    year: 2026
    kind: datasheet
    license: supplier page, cited not reproduced
  goodfellow-lu-pellets:
    title: 'Goodfellow: Lutetium pellets (EU page), property tables'
    id: Goodfellow product group lutetium pellets, CAS 7439-94-3, 99.9% (3N)
    url: https://www.goodfellow.com/eu/lutetium-pellets-group
    year: 2026
    kind: datasheet
    license: supplier page, cited not reproduced
  usgs-mcs2026-rare-earths:
    title: Mineral Commodity Summaries 2026, Rare Earths
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  usgs-pp1802a:
    title: 'Critical Mineral Resources of the United States: An Introduction (Professional Paper 1802-A), Table A1'
    id: USGS PP 1802-A
    url: https://pubs.usgs.gov/pp/1802/a/pp1802a.pdf
    year: 2017
    kind: report
    license: public domain (USGS)
  usgs-crit2025:
    title: About the 2025 List of Critical Minerals (USGS)
    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-lu:
    title: PubChem compound record, Lutetium (CID 23929)
    id: CID 23929; CAS 7439-94-3
    url: https://pubchem.ncbi.nlm.nih.gov/compound/23929
    year: 2026
    kind: database
    license: public domain (NCBI)
  nist-atomic-weights:
    title: NIST Atomic Weights and Isotopic Compositions for All Elements (lutetium entry)
    id: NIST Physical Measurement Laboratory
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=Lu&all=all&ascii=html
    year: 2026
    kind: database
    license: public domain (NIST)
  chemicalbook-lu-sds:
    title: 'ChemicalBook: Lutetium metal, safety data sheet (CB2168799)'
    id: CB2168799; CAS 7439-94-3; revision 2026-08-29
    url: https://www.chemicalbook.com/msds/lutetium.htm
    year: 2026
    kind: datasheet
    license: supplier document, cited not reproduced
  prochem-lu-chips:
    title: 'ProChem: Lutetium, chips (product 2383)'
    id: Product 2383; 99.9%; CAS 7439-94-3
    url: https://prochemonline.com/product/lutetiumchips-2383/
    year: 2026
    kind: datasheet
    license: supplier page, cited not reproduced
  bnc-lyso:
    title: 'BNC: LYSO Scintillators for PET and Fast Timing (datasheet)'
    id: Berkeley Nucleonics LYSO datasheet
    url: https://www.berkeleynucleonics.com/docs/bnc-scintiq-lyso-datasheet.html
    year: 2026
    kind: datasheet
    license: supplier page, cited not reproduced
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 20
  unreachable: 3
  caveats: 4
  note: 'Read by an AI assistant on 2026-10-26 from the pages named in each entry. Unreachable in this run: the EJNMMI Physics LYSO table (publisher redirect blocked), the Fisher SDS page (connection reset) and the EU critical raw materials page (not opened). Caveats: the physical values come from one supplier (Goodfellow) and are not all checked against a second source; the corrosion entries rest on one supplier page and one SDS; supply shares are for all rare earths, not lutetium; the LYSO composition conflicts between two lines on the vendor page.'
story:
  recipe:
    line: Lutetium is a single element, not an alloy or compound. The metal is unalloyed in the disc and pellet products. The scintillator crystal LYSO combines lutetium with yttrium, silicon and oxygen, with cerium as the dopant.
    parts:
      - name: Lutetium
        symbol: Lu
        atoms: 1
        atomic_weight: 174.9668
        role: The element itself. Its high density and high atomic number are what make the LYSO crystal stop gamma rays efficiently.
  risk_groups:
    - title: For people
      level: 1
      verdict: Flammable solid
      lead: The metal is a flammable solid under its supplier SDS, and it releases flammable gas on contact with water. It is not described as toxic in the sources read here.
      points:
        - label: The metal
          line: The SDS classifies it as a flammable solid (H228) with signal word Danger. PubChem records the same H228 classification for 88.2% of company reports.
        - label: Dust and chips
          line: The SDS advises avoiding dust and aerosols, and the chips product page carries the same flammable-solid statement.
        - label: Water
          line: On contact with water it releases flammable gas that can ignite on its own (H260). Keep it away from water and moisture.
    - title: If the metal catches fire
      lead: The SDS gives dry chemical, carbon dioxide or alcohol-resistant foam as extinguishing media. The sources give no decomposition products, so smoke composition is not known.
      points:
        - label: Water
          line: Do not use water on a lutetium fire, because contact with water releases flammable gas.
    - title: Handling and storage
      points:
        - label: Atmosphere
          line: The SDS calls for handling under inert gas and protection from moisture.
        - label: Heat and sparks
          line: Keep the metal away from heat, sparks and open flames. Ground and bond containers, and use explosion-proof equipment.
  why: 'Lutetium is the element Lu, a rare-earth metal with a density of 9.842 g/cm3 and a melting point of 1663 °C. Its practical role is in scintillator crystals: the LYSO used in PET detectors has a density of 7.2 g/cm3, which lets it stop gamma rays in a small volume and gives a fast 50 ns light pulse. Lutetium is one of the least abundant rare earths in the crust, at 0.8 ppm, which is why its supply is a policy question. The metal itself carries a flammable-solid hazard that is more of a handling issue than a toxicity issue.'
  uses:
    - where: Medical imaging detectors
      line: LYSO, a lutetium-yttrium silicate crystal doped with cerium, is used as the scintillator in PET detectors. The BNC datasheet gives a density of 7.2 g/cm3, a decay time of 50 ns and a light yield of 30 photons per keV.
    - where: Medical imaging, electronics and cancer therapy
      line: The USGS 2025 critical-minerals page describes lutetium as used for medical imaging, electronics and some cancer therapies. The cancer use is a radioisotope use, not the metal itself.
  can_do:
    - label: Density
      benchmark: density
      line: The metal has a density of 9.842 g/cm3 at 20 °C (Goodfellow datasheet). The LYSO scintillator is less dense, at 7.2 g/cm3 (BNC datasheet), so the metal's density is not what the detector uses directly.
    - label: Melting point
      benchmark: melting_point
      line: It melts at 1663 °C according to the Goodfellow datasheet. The Wikipedia value of about 1652 °C differs, and the datasheet value is used here.
    - label: Scintillator decay
      value: 50 ns
      line: In the LYSO crystal used for PET detectors, the decay time is 50 ns according to the BNC datasheet, which is what makes fast timing possible.
  compare: Lutetium is a dense, high-melting rare-earth metal that is scarce in the crust, at 0.8 ppm. Rare earths in general are mostly mined in China (about 69% of 2025 mine output, calculated from the USGS table; no lutetium-only figure was found). Its metal is a flammable solid that reacts with water, so it needs dry, inert handling. The most useful form for detection is the crystal LYSO rather than the metal.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Melting point
      benchmark: melting_point
    - label: Thermal conductivity
      benchmark: thermal_conductivity
  handling:
    - The SDS calls for handling under inert gas and protection from moisture.
    - Keep the metal away from heat, sparks and open flames, and avoid dust.
    - Do not use water on a fire. Use dry chemical, carbon dioxide or alcohol-resistant foam.
  good_for:
    - Scintillator detectors. The LYSO crystal gives a fast 50 ns decay and a density of 7.2 g/cm3 (BNC datasheet).
    - Dense metal properties. The metal has a density of 9.842 g/cm3 at 20 °C (Goodfellow datasheet).
  watch_out:
    - Flammable as chips or powder, and reacts with water to release flammable gas.
    - Scarce. The average crustal abundance is 0.8 ppm, and China mined about 69% of world rare-earth output in 2025 (USGS 2026 table, calculated; all rare earths).
    - China's April 2025 export controls named lutetium among the rare earths whose alloys, compounds, metals and oxides are controlled (USGS MCS 2026).
  verdict: Lutetium is a dense, scarce rare-earth metal whose value lies mostly in scintillator crystals such as LYSO. The metal is a flammable solid that needs dry, inert handling, and its supply is concentrated in China.