spore: profile
id: neodymium
spore_version: 0.2
family: rare-earth-metals
name: Neodymium
abbreviation: Nd
role: magnet alloy feedstock and solid-state laser dopant
category: metals
type: heavy-metals
summary: |
  Neodymium is the element Nd (atomic number 60), a silvery-white lanthanide metal with a density of 7.007 g/cm3 at 20 °C and a melting point of 1022 °C in the Wikipedia infobox. It is one of the rare-earth elements and occurs in minerals with the others. The metal is made by electrolysis of neodymium oxide in a molten fluoride salt. Its main uses are as the magnet element in Nd-Fe-B permanent magnets and as the active ion in Nd:YAG and neodymium-glass lasers. The Mars Orbiter Laser Altimeter flew a diode-pumped Nd:YAG transmitter on Mars Global Surveyor, launched on 5 November 1996. The metal tarnishes in air and reacts with water, and its fine chips and powder are flammable, so it needs dry, inert handling.
best_for: Magnet-grade and laser-grade neodymium, where a 1064 nm Nd:YAG laser or a Nd-Fe-B magnet is the goal (Wikipedia, NASA MOLA paper)
weakest_at: Tarnishes in air, reacts with water and releases hydrogen with acids, and fine chips and powder are flammable (Wikipedia, Lesker MSDS)
identity:
  formula: Nd (element, atomic number 60); unalloyed metal, sold by Goodfellow as pellets and foil
  cas: 7440-00-8
  source: pubchem-nd
  where: Names and Identifiers, CAS entry (PubChem CID 23934); EC number 231-109-3 is printed in the PubChem Regulatory Information, REACH entry
tags:
  environments: []
  applications:
    - optics-and-cameras
    - mechanisms
properties:
  - benchmark: density
    label: Density, neodymium (Wikipedia infobox, 20 °C)
    value: 7.007
    unit: g/cm3
    scope: material
    conditions:
      temperature: 20 °C
      unit_in_source: 7.007 g/cm3
    method: Value printed in the Wikipedia infobox
    status: ground
    source: wikipedia-nd
    where: Infobox, row Density (at 20 °C) 7.007 g/cm3
  - benchmark: density
    label: Density, neodymium (PubChem experimental property, 25 °C)
    value: 7.01
    unit: g/cm3
    scope: material
    conditions:
      temperature: 25 °C
    method: Experimental value listed in the PubChem record
    status: ground
    source: pubchem-nd
    where: Chemical and Physical Properties, Experimental Properties, Density (7.01 at 25 °C)
  - benchmark: density
    label: Density, neodymium pellets (Goodfellow, 20 °C)
    value: 7.004
    unit: g/cm3
    scope: material
    conditions:
      temperature: 20 °C
      purity: not stated on the page
    method: Typical value printed in a supplier product datasheet
    status: ground
    source: goodfellow-nd-pellets
    where: Physical Properties table, row Density (7.004@20 °C)
  - benchmark: density
    label: Density, solid neodymium (WebElements)
    value: 6800
    unit: kg/m3
    scope: material
    conditions:
      state: solid
      unit_in_source: 6800 kg m-3
    method: Value printed on the WebElements physical-properties page
    status: ground
    note: WebElements prints 6800 kg/m3 (6.8 g/cm3), about 3 % below the 7.0 g/cm3 values from the other three sources. The page does not say why.
    source: webelements-nd
    where: Density properties, row Density of solid (6800 kg m-3)
  - benchmark: melting_point
    label: Melting point, neodymium (Wikipedia infobox)
    value: 1022
    unit: °C
    scope: material
    conditions:
      pressure: not stated
      unit_in_source: 1295 K (1022 °C, 1872 °F)
    method: Value printed in the Wikipedia infobox
    status: ground
    note: The Wikipedia text gives approximately 1024 °C, while its infobox gives 1022 °C. The infobox value is used here.
    source: wikipedia-nd
    where: Infobox, row Melting point, 1295 K (1022 °C, 1872 °F)
  - benchmark: melting_point
    label: Melting point, neodymium pellets (Goodfellow)
    value: 1021
    unit: °C
    scope: material
    conditions:
      pressure: not stated
    method: Value printed in a supplier product datasheet
    status: ground
    source: goodfellow-nd-pellets
    where: Thermal Properties table, row Melting point (1021)
  - benchmark: boiling_point
    label: Boiling point, neodymium (Wikipedia infobox)
    value: 3074
    unit: °C
    scope: material
    conditions:
      pressure: not stated
      unit_in_source: 3347 K (3074 °C, 5565 °F)
    method: Value printed in the Wikipedia infobox
    status: ground
    source: wikipedia-nd
    where: Infobox, row Boiling point, 3347 K (3074 °C, 5565 °F)
  - benchmark: boiling_point
    label: Boiling point, neodymium pellets (Goodfellow)
    value: 3068
    unit: °C
    scope: material
    conditions:
      pressure: not stated
    method: Value printed in a supplier product datasheet
    status: ground
    note: Goodfellow prints 3068 °C and Wikipedia prints 3074 °C. Both are entered and the difference is kept.
    source: goodfellow-nd-pellets
    where: Physical Properties table, row Boiling point (3068)
  - benchmark: specific_heat
    label: Specific heat capacity, neodymium (Wikipedia infobox)
    value: 190.308
    unit: J/(kg·K)
    scope: material
    conditions:
      temperature: not stated in the infobox
    method: Value printed in the Wikipedia infobox
    status: ground
    note: The infobox gives no temperature. The Goodfellow pellets value is about 8 % higher at 25 °C, and both are entered.
    source: wikipedia-nd
    where: Infobox, row Specific heat capacity 190.308 J/(kg·K)
  - benchmark: specific_heat
    label: Specific heat capacity, neodymium pellets (Goodfellow, 25 °C)
    value: 205
    unit: J/(kg·K)
    scope: material
    conditions:
      temperature: 25 °C
    method: Typical value printed in a supplier product datasheet
    status: ground
    source: goodfellow-nd-pellets
    where: Thermal Properties table, row Specific heat (205@25 °C)
  - benchmark: thermal_conductivity
    label: Thermal conductivity, neodymium (Wikipedia infobox)
    value: 16.5
    unit: W/(m·K)
    scope: material
    conditions:
      temperature: not stated in the infobox
      unit_in_source: 16.5 W/(m⋅K)
    method: Value printed in the Wikipedia infobox
    status: ground
    source: wikipedia-nd
    where: Infobox, row Thermal conductivity 16.5 W/(m⋅K)
  - benchmark: thermal_conductivity
    label: Thermal conductivity, neodymium (WebElements)
    value: 17
    unit: W/(m·K)
    scope: material
    conditions:
      temperature: not stated
    method: Value printed on the WebElements physical-properties page
    status: ground
    source: webelements-nd
    where: Heat and conduction, row Thermal conductivity (17 W m-1 K-1)
  - benchmark: thermal_conductivity
    label: Thermal conductivity, neodymium pellets (Goodfellow, 0 to 100 °C)
    value: 13
    unit: W/(m·K)
    scope: material
    conditions:
      temperature: 0 to 100 °C
    method: Typical value printed in a supplier product datasheet
    status: ground
    note: Goodfellow prints 13 W/(m·K) and Wikipedia prints 16.5 W/(m·K). The gap between sources is about 25 %, so the values are kept with their conditions.
    source: goodfellow-nd-pellets
    where: Thermal Properties table, row Thermal conductivity (13@0-100 °C)
  - benchmark: cte
    label: Coefficient of thermal expansion, neodymium (Wikipedia infobox, 20 °C)
    value: 6.7
    unit: ppm/K
    scope: material
    conditions:
      temperature: 20 °C
      unit_in_source: 6.7 x 10-6 per K
      crystal_form: double hexagonal close-packed, averaged over axes (alpha_average = alpha_V/3)
    method: Value printed in the Wikipedia infobox and footnote; the footnote gives the a-axis value as 4.8 and the c-axis value as 10.5 (x10-6/K) at 20 °C
    status: ground
    source: wikipedia-nd
    where: Infobox, row Thermal expansion 6.7 x 10-6 /K (at 20 °C); footnote a
  - benchmark: cte
    label: Coefficient of thermal expansion, neodymium pellets (Goodfellow, 0 to 100 °C)
    value: 6.7
    unit: ppm/K
    scope: material
    conditions:
      temperature: 0 to 100 °C
    method: Typical value printed in a supplier product datasheet
    status: ground
    source: goodfellow-nd-pellets
    where: Thermal Properties table, row Coefficient of thermal expansion (6.7@0-100 °C)
  - benchmark: cte
    label: Coefficient of thermal expansion, neodymium (WebElements)
    value: 9.6
    unit: ppm/K
    scope: material
    conditions:
      temperature: not stated
      unit_in_source: 9.6 x 10-6 K-1
    method: Value printed on the WebElements physical-properties page
    status: ground
    note: WebElements prints 9.6 x 10-6 K-1, while Wikipedia and Goodfellow both print 6.7. The two values are entered with their sources and not averaged.
    source: webelements-nd
    where: Heat and conduction, row Coefficient of linear thermal expansion (9.6 x 10-6 K-1)
  - benchmark: elastic_modulus
    label: Young's modulus, neodymium (Wikipedia infobox)
    value: 41.4
    unit: GPa
    scope: material
    conditions:
      temperature: not stated in the infobox
    method: Value printed in the Wikipedia infobox
    status: ground
    source: wikipedia-nd
    where: Infobox, row Young's modulus 41.4 GPa
  - benchmark: elastic_modulus
    label: Young's modulus, neodymium (WebElements)
    value: 41
    unit: GPa
    scope: material
    conditions:
      temperature: not stated
    method: Value printed on the WebElements physical-properties page
    status: ground
    source: webelements-nd
    where: Elastic properties, row Young's modulus 41 GPa
  - benchmark: shear_modulus
    label: Shear modulus (rigidity), neodymium (Wikipedia infobox)
    value: 16.3
    unit: GPa
    scope: material
    conditions:
      temperature: not stated in the infobox
    method: Value printed in the Wikipedia infobox
    status: ground
    source: wikipedia-nd
    where: Infobox, row Shear modulus 16.3 GPa
  - benchmark: shear_modulus
    label: Rigidity modulus, neodymium (WebElements)
    value: 16
    unit: GPa
    scope: material
    conditions:
      temperature: not stated
    method: Value printed on the WebElements physical-properties page
    status: ground
    source: webelements-nd
    where: Elastic properties, row Rigidity modulus 16 GPa
  - benchmark: bulk_modulus
    label: Bulk modulus, neodymium (Wikipedia infobox)
    value: 31.8
    unit: GPa
    scope: material
    conditions:
      temperature: not stated in the infobox
    method: Value printed in the Wikipedia infobox
    status: ground
    note: The Wikipedia text gives approximately 33 GPa from ultrasonic measurements, which differs from the infobox. The infobox value is used.
    source: wikipedia-nd
    where: Infobox, row Bulk modulus 31.8 GPa
  - benchmark: bulk_modulus
    label: Bulk modulus, neodymium (WebElements)
    value: 32
    unit: GPa
    scope: material
    conditions:
      temperature: not stated
    method: Value printed on the WebElements physical-properties page
    status: ground
    source: webelements-nd
    where: Elastic properties, row Bulk modulus 32 GPa
  - benchmark: poissons_ratio
    label: Poisson's ratio, neodymium (Wikipedia infobox)
    value: 0.281
    unit: '-'
    scope: material
    conditions:
      temperature: not stated in the infobox
    method: Value printed in the Wikipedia infobox
    status: ground
    source: wikipedia-nd
    where: Infobox, row Poisson ratio 0.281
  - benchmark: poissons_ratio
    label: Poisson's ratio, neodymium (WebElements)
    value: 0.28
    unit: '-'
    scope: material
    conditions:
      temperature: not stated
    method: Value printed on the WebElements physical-properties page
    status: ground
    source: webelements-nd
    where: Elastic properties, row Poisson's ratio 0.28 (no units)
  - benchmark: vickers_hardness
    label: Vickers hardness range, neodymium (Wikipedia infobox)
    value: 345
    value_high: 745
    bound: range
    unit: MPa
    scope: material
    conditions:
      temperature: not stated in the infobox
      note_on_range: the infobox gives a range, not a single test value
    method: Range printed in the Wikipedia infobox
    status: ground
    note: No canonical name exists for hardness, so vickers_hardness is a new name and is listed in gaps. The range is given by Wikipedia without test conditions.
    source: wikipedia-nd
    where: Infobox, row Vickers hardness 345-745 MPa
  - benchmark: vickers_hardness
    label: Vickers hardness, neodymium (WebElements)
    value: 343
    unit: MPa
    scope: material
    conditions:
      temperature: not stated
      unit_in_source: 343 MN m-2
    method: Value printed on the WebElements physical-properties page, given as MN m-2 (equal to MPa)
    status: ground
    note: No canonical name exists for hardness, so vickers_hardness is a new name and is listed in gaps.
    source: webelements-nd
    where: Hardnesses, row Vickers hardness 343 MN m-2
  - benchmark: electrical_resistivity
    label: Electrical resistivity, neodymium polycrystalline (Wikipedia infobox)
    value: 643
    unit: nΩ·m
    scope: material
    conditions:
      temperature: not stated in the infobox
      form: polycrystalline
    method: Value printed in the Wikipedia infobox
    status: ground
    source: wikipedia-nd
    where: Infobox, row Electrical resistivity, poly 643 nΩ⋅m
  - benchmark: electrical_resistivity
    label: Electrical resistivity, neodymium pellets (Goodfellow, 20 °C)
    value: 64
    unit: µOhm·cm
    scope: material
    conditions:
      temperature: 20 °C
      unit_in_source: µOhmcm
    method: Typical value printed in a supplier product datasheet
    status: ground
    note: The Goodfellow value of 64 µOhm·cm equals 640 nΩ·m, which agrees with the Wikipedia value of 643 nΩ·m to within about 0.5 %.
    source: goodfellow-nd-pellets
    where: Electrical Properties table, row Electrical resistivity (64@20 °C)
corrosion:
  - environment: Dry or moist air at room temperature
    headline: The metal tarnishes in air, and its surface oxide can flake away and expose fresh metal.
    effect: Wikipedia says the metal tarnishes in air and that its surface oxide can flake away, exposing fresh metal and letting oxidation continue. The Lesker MSDS says the metal may react with air and atmospheric moisture and may spontaneously catch fire, and it advises avoiding damp conditions.
    rating: moderate
    conditions:
      atmosphere: air and atmospheric moisture
      temperature: room temperature
    source: wikipedia-nd
    where: Chemical properties section, first paragraph on air; Lesker MSDS Section V
  - environment: Air above about 150 °C
    headline: Neodymium oxidises rapidly in air above about 150 °C, so processing needs argon or vacuum.
    effect: The Goodfellow page says neodymium oxidises rapidly in air above about 150 °C, and that all processing requires argon or vacuum. No rate figure is given on the page.
    rating: severe
    conditions:
      temperature: above about 150 °C
      atmosphere: air
    source: goodfellow-nd-general
    where: Property table, Melting Point row note
  - environment: Water
    headline: Neodymium reacts with water, more slowly in cold water and faster in hot water.
    effect: Wikipedia says neodymium is electropositive and reacts with water to give neodymium(III) hydroxide and hydrogen, slowly in cold water and faster in hot water.
    rating: moderate
    conditions:
      temperature: cold and hot water
      form: metal
    source: wikipedia-nd
    where: Chemical properties section, paragraph on water
  - environment: Strong acids
    headline: Contact with strong acids releases hydrogen from the metal.
    effect: The Lesker MSDS says contact with strong acids may cause the evolution of hydrogen. PubChem records the metal as soluble in dilute acids, and Wikipedia says neodymium hydroxide dissolves in hydrochloric acid.
    rating: severe
    conditions:
      acid: strong acids, not named
      temperature: not stated
    source: lesker-nd-msds
    where: Section VII Reactivity Data, Hazardous Decomposition Products
risks:
  hazards:
    - text: 'PubChem GHS summary for neodymium (ECHA C and L notifications, 463 company reports): H228 flammable solid in 34.3 %, H251 self-heating in 33.3 %, H315 skin irritation and H319 eye irritation in 41.9 %, H413 in 10.6 %, with signal word Danger. 261 of 463 reports say the substance does not meet GHS criteria.'
      ghs:
        - H228
        - H251
        - H315
        - H319
        - H413
      source: pubchem-nd
      where: Safety and Hazards, Hazards Identification, GHS Classification
    - text: Wikipedia says that finely divided neodymium metal is flammable and can undergo self-heating sufficient to cause ignition, and that the powder can irritate the skin and eyes.
      ghs: []
      source: wikipedia-nd
      where: Health and safety paragraph, on finely divided metal
    - text: The Kurt J. Lesker neodymium MSDS (last revised 8/13/96) lists the metal as a DOT Flammable Solid and says that grinding or cutting may form an explosive dust-air mixture.
      ghs: []
      source: lesker-nd-msds
      where: Section IV Unusual Fire and Explosion Hazards; Section IX Transportation Requirements
    - text: The Goodfellow page says neodymium chips and turnings are flammable and need inert-atmosphere handling.
      ghs: []
      source: goodfellow-nd-general
      where: Mechanical properties table, Hardness row note
  failure_risks:
    - mode: Fire in fines, chips and turnings
      trigger: Finely divided metal, turnings or dust exposed to air or moisture, or produced by grinding or cutting
      consequence: The metal can self-heat enough to ignite, and the Lesker sheet says it may spontaneously catch fire in air or moisture. Grinding may form an explosive dust-air mixture.
      severity: high
      source: lesker-nd-msds
      where: Section IV Unusual Fire and Explosion Hazards; Section V Steps to be taken in case of spill
    - mode: Oxide spalling and continued oxidation
      trigger: Exposure to air, with the surface oxide flaking away
      consequence: The loose oxide exposes fresh metal, so oxidation continues and the metal keeps tarnishing.
      severity: moderate
      source: wikipedia-nd
      where: Chemical properties section, paragraph on air
    - mode: Hydrogen release on contact with water or strong acid
      trigger: Contact with water (slow in cold water, faster in hot water) or with strong acids
      consequence: Neodymium hydroxide forms and hydrogen gas is released, which is flammable. The Lesker sheet also says strong acids may cause the evolution of hydrogen.
      severity: high
      source: wikipedia-nd
      where: Chemical properties section, paragraph on water; Lesker Section VII
  side_effects:
    - text: The Lesker MSDS says that dust irritates the nose and throat, and that repeated exposure above the recommended limits over a long period can lead to dust in the lungs and, in time, scarring. Section II prints a limit of 15 mg/m3 for neodymium, but the column is not clear in the PDF text.
      affects: Workers who grind, cut or handle the metal in dust form
      source: lesker-nd-msds
      where: Section VI Effects of Overexposure, Inhalation; Section II Hazardous Ingredients
  handling:
    - text: Keep the metal dry and avoid contact with air and moisture. Store it under light mineral oil or take other steps to slow spontaneous oxidation, and use a dry inert atmosphere for machining or handling powder (Lesker MSDS).
      source: lesker-nd-msds
      where: Section IX Precautions to be Taken in Handling and Storing
    - text: Keep the metal away from oxidizing agents, and do not agitate the fine powder in air (Lesker MSDS).
      source: lesker-nd-msds
      where: Section IX Precautions to be Taken in Handling and Storing
    - text: Do not use water or CO2 extinguishers on a neodymium fire. Smother it with dry sand or a dry powder agent made for metal fires (Lesker MSDS).
      source: lesker-nd-msds
      where: Section IV Special Fire Fighting Procedures
    - text: Use local exhaust ventilation, or explosion-proof exhaust where needed, and a NIOSH-approved dust respirator if airborne levels exceed the limits (Lesker MSDS).
      source: lesker-nd-msds
      where: Section VIII Respiratory Protection and Ventilation
  mitigations: []
uses:
  - application: optics-and-cameras
    device: Nd:YAG laser altimeter transmitter on Mars Global Surveyor (MOLA, launched 5 November 1996)
    example: The MOLA transmitter is a diode-pumped Nd:YAG laser at 1.064 µm. Its Table 1 gives an actual pulse energy of 49 mJ and a pulse width of 8.4 ns at 10 Hz, against a specification of 40 mJ and 10 ns. The neodymium enters the laser as the dopant in the garnet crystal, and the metal is the precursor for crystal growth as the oxide (Goodfellow).
    source: mola-nasa-2000
    where: 'Mars Orbiter Laser Altimeter: Laser Transmitter section; Table 1, Specifications and Actual rows'
  - application: optics-and-cameras
    device: Neodymium-glass laser amplifiers at the National Ignition Facility
    example: Wikipedia says flashlamps excite neodymium ions in phosphate-glass slabs at the National Ignition Facility, which amplify infrared pulses at about 1053 nm. The facility's frequency-tripled output is at 351 nm.
    source: wikipedia-nd
    where: Lasers section, paragraph on the National Ignition Facility
  - application: mechanisms
    device: Nd-Fe-B permanent magnets for electric motors and generators, with neodymium as the magnet element
    example: Wikipedia says the larger applications include electric motors in industrial equipment, robots and electric vehicles, and that Nd-Fe-B magnets are also used in the generators of some wind turbines. The metal is the feedstock for the magnet alloy, not the magnet itself.
    source: wikipedia-nd
    where: Magnets section, paragraphs on motors and wind turbines
supply:
  - subject: Rare earths (neodymium is not reported separately by USGS)
    abundance: 41 mg/kg in the Earth's crust (Wikipedia, citing the CRC Handbook)
    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: []
    recycling: 'USGS: limited quantities of rare earths were recovered from batteries, permanent magnets and fluorescent lamps. Wikipedia adds that direct recycling can preserve the magnet alloy for remelting.'
    substitutes:
      - 'USGS: substitutes are available for many applications but generally are less effective.'
    source: usgs-ree-2026
    where: 'World Mine Production table, 2025 (world total 390,000 t; shares calculated by Space Mushroom from China 270,000, United States 51,000, Australia 29,000 and Burma 22,000). Reserves: China 44,000,000 t of more than 75,000,000 t world total. Recycling and Substitutes sections. Abundance: Wikipedia Occurrence section.'
  - subject: Rare-earth compounds and metals imported into the United States
    producers:
      - country: China
        share_percent: 71
        year: 2024
      - country: Malaysia
        share_percent: 13
        year: 2024
      - country: Japan
        share_percent: 5
        year: 2024
      - country: Estonia
        share_percent: 5
        year: 2024
    critical_lists: []
    recycling: ''
    substitutes: []
    source: usgs-ree-2026
    where: Import Sources (2021-24) paragraph; the year column shows the end of the 2021 to 2024 range. Net import reliance for compounds and metals in 2025e is 67 %, from the Salient Statistics table.
  - subject: Neodymium oxide price, 99.5 % minimum
    producers: []
    critical_lists: []
    recycling: ''
    substitutes: []
    source: usgs-ree-2026
    where: 'Salient Statistics, price row Neodymium oxide, 99.5% minimum: 73 dollars per kg in 2025e (56 in 2024)'
  - subject: China export controls, April 2025
    producers: []
    critical_lists: []
    recycling: ''
    substitutes: []
    source: usgs-ree-2026
    where: 'Events, Trends, and Issues: the April 2025 controls named samarium, gadolinium, terbium, dysprosium, lutetium, scandium and yttrium. Neodymium is not in that list in the USGS text.'
documents:
  - title: 'Wikipedia: Neodymium'
    type: database
    url: https://en.wikipedia.org/wiki/Neodymium
    year: 2026
  - title: PubChem compound record for neodymium (CID 23934), including ECHA C and L classification
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/23934
    year: 2026
  - title: 'WebElements: Neodymium, physical properties (University of Sheffield)'
    type: database
    url: https://winter.group.shef.ac.uk/webelements/neodymium/physics.html
    year: 2026
  - title: Goodfellow neodymium pellets, physical and thermal properties (product datasheet)
    type: datasheet
    url: https://www.goodfellow.com/uk/neodymium-pellets-group
  - title: 'Goodfellow rare-earth metals page: neodymium (general properties and applications)'
    type: datasheet
    url: https://www.goodfellow.com/usa/material/rare-earth-metals/neodymium
  - title: 'NIST: Atomic Weights and Isotopic Compositions for Neodymium'
    type: database
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=Nd&all=all
  - title: 'Kurt J. Lesker Company material safety data sheet: Neodymium (last revised 8/13/96)'
    type: sds
    url: https://www.lesker.com/newweb/deposition_materials/pdf/msds_nd.pdf
    year: 1996
  - title: 'Mineral Commodity Summaries 2026: Rare Earths (USGS)'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf
    year: 2026
  - title: Space Operation of the MOLA laser (Afzal, NASA Goddard, 2000 conference paper)
    type: paper
    url: https://ntrs.nasa.gov/api/citations/20000053090/downloads/20000053090.pdf
    year: 2000
gaps:
  - 'Critical-mineral listing: the USGS 2025 critical minerals list and the EU critical raw materials list (Regulation (EU) 2024/1252) could not be opened in this run (the USGS page returned a short error page and the EUR-Lex page returned nothing), so critical_lists is empty.'
  - 'Neodymium-specific production: USGS reports rare earths as one group, so the producer shares above are for all rare earths, not for neodymium alone.'
  - 'Mechanical strength: no tensile or yield datasheet value for neodymium was read in this run. The Goodfellow page gives only an approximate tensile strength of about 200 MPa, which is not entered.'
  - Vickers hardness is entered under the new name vickers_hardness because the property file has no canonical name for it. Hardness is printed in MPa by WebElements and as a range by Wikipedia.
  - The Wikipedia infobox gives an antiferromagnetic transition below 20 K, and WebElements prints a sound speed of 2330 m/s. Neither has a canonical property name, so neither is entered.
  - 'Flight environment: the MOLA laser flew in orbit around Mars, but no environment tag in the allowed list fits Mars orbit, so tags.environments is empty. No vacuum, radiation or thermal-cycling test on the metal itself was found.'
  - Corrosion data are qualitative. No measured oxidation rate or weight-gain figure for neodymium in air or water was found in an opened source.
  - Hazard data rest on a 1996 Lesker sheet (no GHS statements), the PubChem notification summary and the Wikipedia text. No current supplier safety data sheet for the metal was opened in this run, so the most recent classification is not confirmed.
  - Density and thermal values disagree between sources (density 6.8 to 7.01 g/cm3, thermal conductivity 13 to 17 W/(m·K), expansion 6.7 and 9.6 ppm/K). Each value is entered with its own source and conditions, and none is averaged.
  - 'Media: the lithium profile has an images section. No images for neodymium were read in this run, so no media section is included.'
  - 'Recipe: production is given as electrolysis of the oxide (Wikipedia) and calcium reduction of the fluoride (Goodfellow). The process conditions for the industrial route were not read in full.'
sources:
  wikipedia-nd:
    title: Neodymium (Wikipedia)
    url: https://en.wikipedia.org/wiki/Neodymium
    year: 2026
    kind: web
    license: CC BY-SA 4.0 (cited, not reproduced)
  pubchem-nd:
    title: 'PubChem compound record: Neodymium (CID 23934), including ECHA C and L Inventory classification'
    id: CID 23934; CAS 7440-00-8; EC 231-109-3
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23934/JSON
    year: 2026
    kind: database
    license: PubChem (NCBI), public domain; sections attributed to ECHA and others
  webelements-nd:
    title: 'WebElements: Neodymium, physical properties (University of Sheffield)'
    url: https://winter.group.shef.ac.uk/webelements/neodymium/physics.html
    kind: database
    license: WebElements, cited not reproduced
  goodfellow-nd-pellets:
    title: Neodymium pellets, physical and thermal properties (Goodfellow product datasheet)
    url: https://www.goodfellow.com/uk/neodymium-pellets-group
    kind: datasheet
    license: supplier web page (cited, not reproduced)
  goodfellow-nd-general:
    title: Neodymium, rare-earth metals page (Goodfellow)
    url: https://www.goodfellow.com/usa/material/rare-earth-metals/neodymium
    kind: datasheet
    license: supplier web page (cited, not reproduced)
  nist-nd:
    title: 'NIST: Atomic Weights and Isotopic Compositions for Neodymium'
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl?ele=Nd&all=all
    kind: database
    license: NIST public domain
  lesker-nd-msds:
    title: 'Kurt J. Lesker Company material safety data sheet: Neodymium (last revised 8/13/96)'
    url: https://www.lesker.com/newweb/deposition_materials/pdf/msds_nd.pdf
    year: 1996
    kind: datasheet
    license: supplier safety data sheet, cited not reproduced
  usgs-ree-2026:
    title: 'Mineral Commodity Summaries 2026: Rare Earths (USGS)'
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  mola-nasa-2000:
    title: Space Operation of the MOLA laser (Afzal, NASA Goddard Space Flight Center, 2000)
    id: NTRS 20000053090
    url: https://ntrs.nasa.gov/api/citations/20000053090/downloads/20000053090.pdf
    year: 2000
    kind: paper
    license: public domain (NASA)
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 28
  unreachable: 2
  caveats: 6
  note: 'Read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable: the USGS 2025 critical minerals page and the EUR-Lex page for Regulation (EU) 2024/1252. Caveats: most physical values differ between sources, the hazard classifications are from a 1996 sheet and PubChem notifications, the production shares are for all rare earths, and the critical-mineral lists are empty.'
story:
  risk_groups:
    - title: For people
      level: 1
      verdict: Fine dust and chips are the main concern
      lead: The hazard is in the metal's form. Solid pieces are less hazardous than chips, turnings and dust, which can ignite, and the powder can irritate skin and eyes.
      points:
        - label: Chips and dust
          line: Finely divided metal is flammable and can self-heat enough to ignite (Wikipedia). The 1996 Lesker sheet says grinding or cutting may form an explosive dust-air mixture.
        - label: GHS notifications
          line: PubChem records H228 (flammable solid) in 34.3 % of 463 company reports and H251 (self-heating) in 33.3 %. 261 of the reports say the substance does not meet GHS criteria.
        - label: Skin and eyes
          line: PubChem records H315 and H319 (skin and eye irritation) in 41.9 % of reports, and Wikipedia says the powder can irritate the skin and eyes.
        - label: Dust limit
          line: The Lesker sheet lists a limit of 15 mg/m3 for neodymium, and warns that repeated overexposure to dust can scar lung tissue.
    - title: If it fails
      lead: 'The sources give three failure routes: a fire in fines, oxide spalling in air, and hydrogen release with water or strong acid.'
      points:
        - label: Fire
          line: Fines and turnings may ignite spontaneously in air or moisture. The Lesker sheet says to smother a fire with dry sand or a dry powder agent, and not to use water or CO2.
        - label: Air
          line: The metal tarnishes in air, and the oxide can flake away and expose fresh metal to further oxidation (Wikipedia).
        - label: Water and acids
          line: Neodymium reacts with water to release hydrogen, slowly in cold water and faster in hot water. Strong acids may also release hydrogen (Wikipedia, Lesker).
    - title: Handling and storage
      points:
        - label: Keep it dry
          line: Keep the metal dry and sealed, under light mineral oil or in a dry inert atmosphere. Handle powder in an inert atmosphere when machining (Lesker).
        - label: Fire agents
          line: Use dry sand or a dry powder agent for metal fires, and do not use water or CO2 extinguishers (Lesker).
  why: Neodymium is a rare-earth metal whose uses come from its 4f electrons. It is the magnet element in Nd-Fe-B permanent magnets, the strongest class of magnet in common use, and it is the active ion in Nd:YAG and neodymium-glass lasers. The Nd:YAG line at 1064 nm is the one that a 1996 Mars orbiter used for laser altimetry. The metal itself is not a structural material. Its value to a spacecraft comes from the laser and magnet applications, not from the bare metal.
  uses:
    - where: Laser altimetry in orbit around Mars
      line: The Mars Orbiter Laser Altimeter on Mars Global Surveyor, launched on 5 November 1996, used a diode-pumped Nd:YAG transmitter at 1.064 µm. The NASA paper reports 49 mJ actual pulse energy at 10 Hz, against a specification of 40 mJ.
    - where: Neodymium-glass lasers
      line: Wikipedia says that flashlamps excite neodymium ions in phosphate-glass slabs at the National Ignition Facility, which amplify infrared pulses at about 1053 nm.
    - where: Permanent magnets in motors and generators
      line: Wikipedia says that Nd-Fe-B magnets are used in electric motors for industrial equipment, robots and electric vehicles, and in the generators of some wind turbines. Neodymium is the feedstock for the magnet alloy.
  can_do:
    - label: Weight
      value: 7.007 g/cm3
      benchmark: density
      line: Density is 7.007 g/cm3 at 20 °C in the Wikipedia infobox, and 7.004 g/cm3 at 20 °C for Goodfellow pellets.
    - label: Melting
      value: 1022 °C
      benchmark: melting_point
      line: Melting point is 1022 °C in the Wikipedia infobox, and 1021 °C for Goodfellow pellets.
    - label: Stiffness
      value: 41.4 GPa
      benchmark: elastic_modulus
      line: Young's modulus is 41.4 GPa in the Wikipedia infobox, and 41 GPa on WebElements.
    - label: Heat conduction
      value: 16.5 W/(m·K)
      benchmark: thermal_conductivity
      line: Thermal conductivity is 16.5 W/(m·K) in the Wikipedia infobox, 17 W/(m·K) on WebElements and 13 W/(m·K) from Goodfellow at 0 to 100 °C.
    - label: Laser wavelength
      value: 1064 nm
      line: Nd:YAG emits at 1064 nm through a four-level transition, as the Wikipedia text states. The MOLA transmitter also operated at 1.064 µm.
  compare: Neodymium is a light, soft rare-earth metal, with a density of about 7.0 g/cm3 and a melting point near 1022 °C. Its thermal conductivity of 13 to 17 W/(m·K) is low for a metal, and its Young's modulus of about 41 GPa is modest. Its value comes from its magnetic and optical behaviour rather than from its strength. The metal tarnishes in air and reacts with water, so it needs dry handling. No comparison profile is carried in this file, so the rows below list neodymium values only.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Melting point
      benchmark: melting_point
    - label: Thermal conductivity
      benchmark: thermal_conductivity
  recipe:
    line: Neodymium is a single-element metal (Nd). Wikipedia says the industrial route is electrolysis of neodymium oxide dissolved in a molten mixture of neodymium(III) fluoride and lithium fluoride, where the neodymium ions are reduced at the cathode and the molten metal collects at the bottom of the cell. Goodfellow says the metal is produced by calcium reduction of neodymium fluoride.
    parts:
      - name: Neodymium
        symbol: Nd
        atoms: 1
        atomic_weight: 144.242
        role: The whole material. NIST prints the standard atomic weight as 144.242. Goodfellow pellets and foil are the forms sold.
  handling:
    - Keep the metal dry and sealed under light mineral oil, or in a dry inert atmosphere (Lesker MSDS).
    - Keep it away from oxidizing agents, and do not agitate the fine powder in air (Lesker MSDS).
    - Do not use water on a fire. Smother it with dry sand or a dry powder agent for metal fires (Lesker MSDS).
    - Use local exhaust ventilation and a dust respirator if airborne levels exceed the limits (Lesker MSDS).
  good_for:
    - 'Nd:YAG laser media: the 1064 nm line was used for laser altimetry on Mars Global Surveyor (NASA).'
    - 'Permanent magnets: neodymium is the magnet element in Nd-Fe-B, used in motors and wind turbine generators (Wikipedia).'
    - 'Neodymium-glass lasers: the National Ignition Facility amplifies infrared pulses at about 1053 nm (Wikipedia).'
  watch_out:
    - Fine chips, turnings and dust are flammable, and the metal can self-heat enough to ignite (PubChem, Lesker).
    - The metal tarnishes in air and reacts with water and acids to release hydrogen (Wikipedia, Lesker).
    - 'Supply is concentrated: China produced about 69 % of world rare-earth mine output in 2025, and neodymium is not named in the April 2025 Chinese export-control list (USGS).'
    - The sources disagree on several physical values, so each figure must be checked against its own source and conditions.
  verdict: Neodymium metal is a dense rare-earth metal with a melting point of 1022 °C. Its value is as the magnet element in Nd-Fe-B permanent magnets and as the active ion in Nd:YAG and neodymium-glass lasers, not as a structural metal. The metal needs dry handling, because its fines can ignite and it reacts with water.