spore: profile
id: magnesium
spore_version: 0.2
family: magnesium-alloys
name: Magnesium (pure metal)
abbreviation: Mg
role: light structural metal, alloying base and reducing metal
category: metals
type: magnesium
summary: |
  Pure magnesium is the lightest common structural metal, at 1.74 g/cm3 at 20 degC (Goodfellow). It melts at 650 degC and is hexagonal close-packed, so it bends less easily than aluminium at room temperature. Its weak point is chemistry: it is the most electrochemically active structural metal, the native oxide film gives little protection in chloride, and finely divided powder or ribbon ignites in air. Most magnesium sold for structures is an alloy such as AZ31B; this profile covers the unalloyed metal in ingot, ribbon and powder form.
best_for: Light, unalloyed magnesium for research and for alloying or reducing use, such as Kroll-process titanium production and magnesium-ion battery anode research, where the purity matters more than structural strength.
weakest_at: Strength and corrosion resistance. Goodfellow gives 140 to 160 MPa tensile strength for pure magnesium against 260 MPa for wrought AZ31, and says chlorides break down the passive film. Powder and ribbon are pyrophoric.
identity:
  formula: Mg, elemental magnesium metal (hexagonal close-packed crystal; Goodfellow gives a = 3.209 A, c = 5.211 A)
  cas: 7439-95-4
  source: goodfellow-mg-metal
  where: Identifier table (CAS Number 7439-95-4; Symbol Mg; Atomic Number 12); Crystal Structure row of the General Properties table
tags:
  environments: []
  applications:
    - electronics-and-chips
    - batteries
properties:
  - benchmark: density
    label: Density at 20 degC, supplier listing
    value: 1.74
    unit: g/cm3
    scope: material
    conditions:
      temperature: 20 °C
      form: pure magnesium metal (not an alloy)
    method: General Properties table of a supplier product page, Density row
    status: ground
    source: goodfellow-mg-metal
    where: General Properties table, Density (20 °C) row
  - benchmark: density
    label: Density, Merck Index value quoted by PubChem
    value: 1.738
    unit: g/cm3
    scope: material
    conditions:
      temperature: 20 °C
      basis: value printed in the Experimental Properties section; PubChem cites the Merck Index, 13th edition
    method: Experimental Properties, Density entry of the PubChem record
    status: ground
    source: pubchem-mg
    where: Chemical and Physical Properties, Experimental Properties, Density (Merck Index entry)
  - benchmark: melting_point
    value: 650
    unit: °C
    scope: material
    conditions:
      basis: printed as 650 °C (923 K) on the supplier page
    method: General Properties table of a supplier product page, Melting Point row
    status: ground
    source: goodfellow-mg-metal
    where: General Properties table, Melting Point row
  - benchmark: boiling_point
    value: 1090
    unit: °C
    scope: material
    conditions:
      pressure: 760 mmHg
    method: Experimental Properties, Boiling Point entry of the PubChem record
    status: ground
    source: pubchem-mg
    where: Chemical and Physical Properties, Experimental Properties, Boiling Point (1090 °C @760 [mm Hg])
  - benchmark: thermal_conductivity
    value: 156
    unit: W/m·K
    scope: material
    conditions:
      temperature: not stated on the page
      form: pure magnesium metal
    method: General Properties table of a supplier product page, Thermal Conductivity row (printed as W/m·K)
    status: ground
    source: goodfellow-mg-metal
    where: General Properties table, Thermal Conductivity row
  - benchmark: electrical_resistivity
    value: 45.4
    unit: nΩ·m
    scope: material
    conditions:
      temperature: 20 °C
    method: General Properties table of a supplier product page, Electrical Resistivity row
    status: ground
    source: goodfellow-mg-metal
    where: General Properties table, Electrical Resistivity row
  - benchmark: elastic_modulus
    value: 45
    unit: GPa
    scope: material
    conditions:
      temper: annealed (table is headed Pure Mg, Annealed)
      temperature: not stated
    method: Mechanical Properties table (Pure Mg, Annealed) of a supplier product page
    status: ground
    source: goodfellow-mg-metal
    where: Mechanical Properties (Pure Mg, Annealed) table, Elastic (Young's) Modulus row
  - benchmark: poissons_ratio
    value: 0.29
    unit: '-'
    scope: material
    conditions:
      temper: annealed (table is headed Pure Mg, Annealed)
      basis: polycrystalline form, as the page states
    method: Mechanical Properties table (Pure Mg, Annealed) of a supplier product page
    status: ground
    source: goodfellow-mg-metal
    where: Mechanical Properties (Pure Mg, Annealed) table, Poisson's Ratio row
  - benchmark: ultimate_tensile_strength
    label: Tensile strength, pure magnesium, annealed
    value: 140
    value_high: 160
    bound: range
    unit: MPa
    scope: material
    conditions:
      temper: annealed (table is headed Pure Mg, Annealed)
      basis: value printed for pure Mg in the Tensile Strength (Alloys) row; the same row gives 180 to 350 MPa for alloys
    method: Mechanical Properties table (Pure Mg, Annealed) of a supplier product page
    status: ground
    source: goodfellow-mg-metal
    where: Mechanical Properties (Pure Mg, Annealed) table, Tensile Strength (Alloys) row
  - benchmark: hardness_vickers
    label: Hardness, Vickers, annealed
    value: 35
    unit: HV
    scope: material
    conditions:
      temper: annealed
    method: Mechanical Properties table (Pure Mg, Annealed) of a supplier product page; printed as approximately 35 HV, with Mohs about 2.5
    status: ground
    note: Printed with a tilde (about 35). Not in spores/property-canon.yaml, so the snake_case name hardness_vickers is used.
    source: goodfellow-mg-metal
    where: Mechanical Properties (Pure Mg, Annealed) table, Hardness row
  - benchmark: standard_electrode_potential
    label: Standard electrode potential
    value: -2.37
    unit: V vs SHE
    scope: material
    conditions:
      basis: as printed on the supplier page
    method: Chemical Properties table of a supplier product page, Corrosion Behavior row
    status: ground
    note: Not in spores/property-canon.yaml, so the snake_case name standard_electrode_potential is used.
    source: goodfellow-mg-metal
    where: Chemical Properties table, Corrosion Behavior row
  - benchmark: atomic_mass
    label: Atomic mass
    value: 24.305
    unit: u
    scope: material
    conditions:
      basis: standard atomic weight range printed by Wikipedia as 24.304 to 24.307 (abridged 24.305 plus or minus 0.002)
    method: General Properties table of a supplier product page, Atomic Mass row
    status: ground
    note: Not in spores/property-canon.yaml, so the snake_case name atomic_mass is used.
    source: goodfellow-mg-metal
    where: General Properties table, Atomic Mass row
  - benchmark: ignition_temperature
    label: Ignition temperature, ribbon
    value: 650
    unit: °C
    scope: material
    conditions:
      form: ribbon
      basis: printed as about 650 °C on the supplier page
    method: Combustion table of a supplier product page
    status: ground
    note: Not in spores/property-canon.yaml, so the snake_case name ignition_temperature is used. The page gives one figure for ribbon and does not give a powder value.
    source: goodfellow-mg-metal
    where: Combustion row (ignition temperature about 650 °C, ribbon); Reactivity with Water and Air row
  - benchmark: autoignition_temperature
    label: Autoignition temperature, turnings
    value: 473
    unit: °C
    scope: material
    conditions:
      form: turnings
      basis: PubChem notes the value may be lower for finer forms
    method: Experimental Properties, Autoignition Temperature entry of the PubChem record (cites NFPA Fire Protection Guide, 2002)
    status: ground
    note: Not in spores/property-canon.yaml, so the snake_case name autoignition_temperature is used. Finer powder ignites at a lower temperature, so this is an upper figure for powder.
    source: pubchem-mg
    where: Chemical and Physical Properties, Experimental Properties, Autoignition Temperature (883 °F (473 °C) for turnings)
  - benchmark: combustion_burn_rate
    label: Burn rate in oxygen
    value: 25
    unit: MJ/kg
    scope: material
    conditions:
      basis: printed as about 25 MJ/kg on the supplier page
    method: Combustion table of a supplier product page
    status: ground
    note: Not in spores/property-canon.yaml, so the snake_case name combustion_burn_rate is used.
    source: goodfellow-mg-metal
    where: Combustion row
corrosion:
  - environment: Chloride solution, including 3.5 % NaCl saturated with Mg(OH)2 (electrochemical and weight-loss tests)
    headline: Pure magnesium corrodes in chloride. This source gives no numerical rate for the pure metal.
    effect: The 2012 Corrosion Science study (Qiao and co-authors, Hereon record) tested high-purity magnesium ingot in 3.5 % NaCl saturated with Mg(OH)2 for up to 14 days. The abstract says the electrochemical corrosion rate was consistently lower than the weight-loss and hydrogen-evolution rates. The supplier page says the native MgO and Mg(OH)2 film is disrupted in chloride environments.
    rating: unknown
    conditions:
      temperature: not stated
      duration: up to 14 days
      basis: abstract only; the study's rate figures were not readable, so no rate is given here
    source: qiao2012
    where: Abstract
  - environment: Dry or moist air, and water (room temperature and steam)
    headline: Magnesium reacts slowly with water at room temperature and faster with steam.
    effect: The supplier page says bulk magnesium reacts slowly with liquid water at room temperature but rapidly with steam, and that the MgO and Mg(OH)2 passive film formed in dry air gives only limited protection.
    rating: unknown
    conditions:
      temperature: room temperature to steam
      basis: qualitative statements; no rate or mass gain was read
    source: goodfellow-mg-metal
    where: Chemical Properties table, Reactivity with Water and Air row; Corrosion Behavior row
  - environment: Galvanic contact with aluminium, steel or copper
    headline: Galvanic corrosion is severe unless the parts are electrically isolated.
    effect: The supplier page says magnesium has poor galvanic compatibility with most structural metals, and that galvanic corrosion with coupled aluminium, steel or copper is severe unless components are electrically isolated. Conversion coatings, anodising (PEO or MAO) and rare earth alloying are named as protective strategies.
    rating: severe
    conditions:
      basis: qualitative statement from the supplier page; no test result was read
    source: goodfellow-mg-metal
    where: Chemical Properties table, Corrosion Behavior row
  - environment: Chloride solutions at three concentrations, 24 h immersion (pure magnesium and AZ31B-H24)
    headline: The 2015 Corrosion study compared several ways of measuring pure magnesium corrosion in chloride.
    effect: The 2015 Corrosion paper (Bland, King, Birbilis and Scully) compared electrochemical impedance, hydrogen collection, weight loss and ICP-OES on pure magnesium and AZ31B-H24 over 24 h immersion in three chloride concentrations. The abstract gives no numerical rates, so the study adds method context, not a value.
    rating: unknown
    conditions:
      duration: 24 h immersion
      basis: abstract only; the chloride concentrations are not stated numerically on the record
    source: bland2015
    where: Abstract
risks:
  hazards:
    - text: PubChem's aggregated GHS reports for magnesium metal (2,205 company reports from 27 ECHA notifications) give H228 (flammable solid) in 44.9% of reports, H250 (catches fire spontaneously if exposed to air) in 36.5%, H260 (in contact with water releases flammable gases which may ignite spontaneously) in 36.7%, H261 (in contact with water releases flammable gas) in 44.8% and H252 (self-heating in large quantities; may catch fire) in 18%. 18.4% of reports (405 of 2,205) say the element does not meet GHS criteria. These are element-level statements, not a classification of a particular powder or ribbon.
      ghs:
        - H228
        - H250
        - H260
        - H261
        - H252
      source: pubchem-mg
      where: Safety and Hazards, GHS Classification (CID 5462224)
    - text: 'Fire fighting: PubChem''s CHRIS and ERG (Guide 138) excerpts say not to use water, foam, halogenated agents or carbon dioxide on a magnesium fire, and to use dry sand, dry powder or inert powders such as graphite, limestone or salt. The Goodfellow page says burning magnesium cannot be put out with CO2 or N2.'
      ghs: []
      source: pubchem-mg
      where: Safety and Hazards, Fire Hazards and Fire Fighting sections
    - text: The Goodfellow page says the bright white flame of burning magnesium emits strong ultraviolet and visible light, and can cause permanent eye damage on direct viewing without UV-filtering eye protection.
      ghs: []
      source: goodfellow-mg-metal
      where: Combustion row
  failure_risks:
    - mode: Ignition of powder or ribbon in air
      trigger: Finely divided powder or ribbon exposed to air, or heating to about 650 degC for ribbon (Goodfellow) or about 473 degC for turnings (PubChem)
      consequence: Vigorous burning. The Goodfellow page says magnesium fires cannot be extinguished with water or CO2, and that powder with more than 50% magnesium ignites readily in air (PubChem reactivity text).
      severity: high
      source: goodfellow-mg-metal
      where: Combustion row; Reactivity with Water and Air row; PubChem Reactivity Profile (powder over 50% magnesium ignites readily in air) is cited in the same record
    - mode: Reaction with water
      trigger: Contact with water or moist air
      consequence: Flammable hydrogen gas is released and may ignite spontaneously (H260, H261). The PubChem ERG excerpt says some reactions with water are vigorous or explosive.
      severity: high
      source: pubchem-mg
      where: GHS Classification, H260 and H261 statements; Fire Hazards (ERG Guide 138)
    - mode: Explosive or friction-sensitive mixtures
      trigger: Finely divided magnesium mixed with oxidisers, for example potassium or sodium perchlorate, potassium chlorate or nitric acid
      consequence: PubChem's reactivity profile lists several explosive or friction-sensitive mixtures with powdered magnesium.
      severity: high
      source: pubchem-mg
      where: Stability and Reactivity, Reactivity Profile
    - mode: Chloride corrosion of unprotected metal
      trigger: Immersion or wet contact with chloride solutions
      consequence: Corrosion rate is not given here as a number for pure metal. The supplier page says the passive film is disrupted in chloride environments, and that galvanic corrosion with other metals is severe unless isolated.
      severity: moderate
      source: goodfellow-mg-metal
      where: Chemical Properties table, Corrosion Behavior row
  side_effects: []
  handling:
    - text: The Goodfellow page says to keep magnesium dry and away from water. PubChem says contact with water releases flammable gas (H261).
      source: pubchem-mg
      where: GHS Classification, H260 and H261 statements (CID 5462224)
    - text: Keep a dry sand, dry graphite or Met-L-X powder ready for fire fighting. The Goodfellow page says water and CO2 cannot be used on magnesium fires.
      source: goodfellow-mg-metal
      where: Chemical Properties table, Reactivity with Water and Air and Combustion rows
    - text: Keep powder away from strong oxidisers, chlorine, nitric acid and perchlorates. PubChem lists explosive or friction-sensitive mixtures with these.
      source: pubchem-mg
      where: Stability and Reactivity, Reactivity Profile
    - text: Melt and cast under a protective cover gas such as SF6 or CO2/SO2, because molten magnesium ignites readily in air.
      source: goodfellow-mg-metal
      where: General Properties table, Melting Point row
  mitigations:
    - text: Goodfellow lists conversion coatings, anodising (PEO or MAO), and rare earth alloying as protective strategies for magnesium against corrosion.
      source: goodfellow-mg-metal
      where: Chemical Properties table, Corrosion Behavior row
uses:
  - application: electronics-and-chips
    device: Magnesium laptop shells and die-cast housings
    example: Goodfellow says a typical magnesium laptop shell weighs 30 to 40 percent less than an equivalent aluminium die-cast housing. The page's example is for magnesium alloys rather than pure metal.
    source: goodfellow-mg-metal
    where: Applications section, electronics housings paragraph
  - application: batteries
    device: Magnesium-ion battery anode (research stage)
    example: Goodfellow calls magnesium an emerging anode material for next-generation magnesium-ion batteries. This is a research use, not a product in the sources read.
    source: goodfellow-mg-metal
    where: Uses paragraph (pyrotechnics, Kroll process, implants and batteries)
supply:
  - subject: Magnesium metal, world primary (smelter) production, 2025
    abundance: 'USGS: resources for magnesium range from large to virtually unlimited and are globally widespread; magnesium-bearing brines are estimated to be a resource in the billions of tons.'
    producers:
      - country: China
        share_percent: 87.7
        year: 2025
      - country: Russia
        share_percent: 5.5
        year: 2025
      - country: Brazil
        share_percent: 1.8
        year: 2025
      - country: Israel
        share_percent: 1.8
        year: 2025
      - country: Turkey
        share_percent: 1.4
        year: 2025
      - country: Kazakhstan
        share_percent: 1.2
        year: 2025
      - country: Iran
        share_percent: 0.5
        year: 2025
      - country: United States
        share_percent: 0
        year: 2025
    critical_lists:
      - list: 'USGS 2025 List of Critical Minerals: Magnesium, used in metal alloys used by aerospace, automotive and electronics industries'
        listed: true
    recycling: 'USGS: about 110 thousand t of secondary magnesium was recovered from scrap in 2025 (estimate); about 26,000 tons from old scrap and 82,000 tons from new scrap. The only US primary smelter, in Utah, stopped production in 2022, and its operator filed for Chapter 11 in September 2025.'
    substitutes:
      - 'USGS: aluminium and zinc may substitute for magnesium in castings and wrought products. Magnesium''s light weight is an advantage over them in most applications; its high cost is a disadvantage.'
    source: usgs-mcs2026-magnesium-metal
    where: 'World Primary Production and Reserves table, smelter production 2025 (tonnages in thousand t: China 950, Russia 60, Brazil 20, Israel 20, Turkey 15, Kazakhstan 13, Iran 5; world total 1,100 rounded). Shares calculated by Space Mushroom over the sum of the listed 2025 values (1,083 thousand t). Recycling; Substitutes; Events, Trends and Issues.'
  - subject: Magnesium metal imported to the United States, 2021 to 2024 (99.8 % purity)
    producers:
      - country: Israel
        share_percent: 47
      - country: Turkey
        share_percent: 31
      - country: Russia
        share_percent: 8
      - country: China
        share_percent: 6
    source: usgs-mcs2026-magnesium-metal
    where: Import Sources (2021-24), magnesium metal (99.8% purity) row; the other 8% is not listed by country
documents:
  - title: 'Goodfellow: High-Purity Magnesium Metal, product page with general, mechanical and chemical property tables'
    type: datasheet
    url: https://www.goodfellow.com/usa/material/metals/magnesium
  - title: 'USGS Mineral Commodity Summaries 2026: Magnesium Metal'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-magnesium-metal.pdf
    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
  - title: 'PubChem: Magnesium, CID 5462224, Safety and Hazards, GHS Classification and Experimental Properties'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/5462224
  - title: Corrosion behaviour of a nominally high purity Mg ingot produced by permanent mould direct chill casting (Corrosion Science, 2012)
    type: paper
    url: https://publications.hzg.de/id/29895/index.php
    year: 2012
  - title: Assessing the corrosion of commercially pure magnesium and AZ31B (Corrosion, NACE, 2015)
    type: paper
    url: https://research.monash.edu/en/publications/assessing-the-corrosion-of-commercially-pure-magnesium-and-commer/
    year: 2015
  - title: 'AircraftMaterialsUK technical data sheet: Magnesium Alloy AZ31B (for the composition comparison only)'
    type: datasheet
    url: https://aircraftmaterials.com/data/magnesium/az31b.html
  - title: 'Wikipedia: Magnesium (history, crystal structure, standard atomic weight)'
    type: report
    url: https://en.wikipedia.org/wiki/Magnesium
gaps:
  - Specific heat and coefficient of thermal expansion for pure magnesium were not found in a readable source in this run. The AZ31B figures are for an alloy and are not used here.
  - No numerical corrosion rate for pure magnesium was read. The Corrosion Science 2012 and Corrosion 2015 records are abstract pages with no rate values, and the Elsevier full text (doi 10.1016/j.jma.2022.08.003) and the Atrens 2020 review could not be opened. The corrosion rating for each entry is therefore unknown or qualitative.
  - Impurity limits for the 99.9% (3N) grade and the 99.8%+ ingot were not found as a table. The Goodfellow page gives only the purity figures; the USGS import line gives 99.8% purity.
  - No UNS, EN, ASTM or other grade designation for unalloyed magnesium was read, so identity.designations is empty.
  - No safety data sheet for pure magnesium powder or ribbon was opened. Hazard data rest on PubChem's element-level GHS summary, the ERG excerpts it carries, and the Goodfellow page.
  - Ribbon ignition temperature (about 650 degC) and powder ignition behaviour are reported without a test method. The 473 degC figure is for turnings and PubChem notes finer forms ignite lower.
  - Specific heat, Mohs-type and Brinell hardness rows, and electrode data at temperatures other than 20 degC were not found.
  - Space and cryogenic data (outgassing, radiation, thermal-vacuum) were not searched for pure magnesium. The uses listed are terrestrial.
  - Hardness and ignition property names (hardness_vickers, ignition_temperature, autoignition_temperature, combustion_burn_rate, standard_electrode_potential, atomic_mass) are not in spores/property-canon.yaml and are used as snake_case names.
  - EU critical raw materials list not read for magnesium, so no EU listing is recorded.
  - No images were read in this run, so the media section is not included.
  - Wikipedia is used for crystal structure, history and standard atomic weight only.
sources:
  goodfellow-mg-metal:
    title: 'Goodfellow: High-Purity Magnesium Metal (general, mechanical and chemical property tables)'
    url: https://www.goodfellow.com/usa/material/metals/magnesium
    kind: datasheet
    license: Supplier web page, cited and not reproduced
  usgs-mcs2026-magnesium-metal:
    title: 'USGS Mineral Commodity Summaries 2026: Magnesium Metal'
    id: USGS MCS 2026, February 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-magnesium-metal.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)
    url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
    year: 2025
    kind: web
    license: public domain (USGS)
  pubchem-mg:
    title: 'Magnesium, PubChem compound CID 5462224: Safety and Hazards, GHS Classification; Experimental Properties'
    id: PubChem CID 5462224; GHS aggregated from ECHA C&L notifications
    url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/5462224/JSON
    kind: database
    license: PubChem (NCBI) public data
  qiao2012:
    title: Corrosion behaviour of a nominally high purity Mg ingot produced by permanent mould direct chill casting (Qiao, Shi, Hort, Abidin, Atrens; Corrosion Science 61, 185-207)
    id: doi:10.1016/j.corsci.2012.04.030
    url: https://publications.hzg.de/id/29895/index.php
    year: 2012
    kind: paper
    license: publisher record (abstract read)
  bland2015:
    title: Assessing the corrosion of commercially pure magnesium and AZ31B (Bland, King, Birbilis, Scully; Corrosion 71(2), 128-145)
    id: doi:10.5006/1419
    url: https://research.monash.edu/en/publications/assessing-the-corrosion-of-commercially-pure-magnesium-and-commer/
    year: 2015
    kind: paper
    license: publisher record (abstract read)
  aircraftmaterials-az31b:
    title: 'AircraftMaterialsUK technical data sheet: Magnesium Alloy AZ31B (composition limits)'
    url: https://aircraftmaterials.com/data/magnesium/az31b.html
    kind: datasheet
    license: Stockist web page, cited and not reproduced
  wikipedia-magnesium:
    title: 'Wikipedia: Magnesium'
    url: https://en.wikipedia.org/wiki/Magnesium
    kind: web
    license: CC BY-SA (Wikipedia), cited for history, structure and atomic weight only
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 15
  unreachable: 2
  caveats: 3
  note: 'Written 2026-10-26 from pages fetched in this run. Values are as printed, except shares in supply that are calculated from printed tonnages. No pure-magnesium corrosion rate was read: the two corrosion papers are abstract pages without rates, and the full-text journal pages could not be opened.'
story:
  recipe:
    line: Unalloyed magnesium metal, Mg, with atomic mass 24.305 u. Goodfellow sells it as ingot (99.8% or higher, for Kroll-process titanium production), ribbon, powder, foil, rod and wire, mostly at 99.9% (3N) purity. Goodfellow describes the Pidgeon process, which reduces magnesium oxide with silicon under vacuum, and the metal is also recovered from brine by electrolysis. The US primary smelter in Utah stopped in 2022.
    parts:
      - name: Magnesium
        symbol: Mg
        atoms: 1
        atomic_weight: 24.305
        share_note: 99.8% or higher (ingot, Goodfellow), 99.9% (3N) (foil and powder listings); the rest is impurities
        role: The whole metal. It is the reducing agent in the Kroll process and the active material in an anode, and it is the structural metal in its own right.
        source: goodfellow-mg-metal
        where: General Properties table, Atomic Mass row; Metal Reduction section (ingot 99.8%+); title line (Mg 99.9% 3N)
      - name: Impurity limits
        symbol: Fe, Ni, Cu, Si, Mn
        share_note: not given for the pure grades in the sources read
        role: Impurities control corrosion. Pure grades are chosen to keep iron, nickel and copper low; no limit table was read.
        source: goodfellow-mg-metal
        where: Gap noted; not read
  risk_groups:
    - title: For people
      lead: The only hazard data are PubChem's element-level GHS summary and the Goodfellow notes on fire. Neither classifies a specific powder or ribbon.
      gap: No safety data sheet for pure magnesium powder or ribbon was opened.
      points:
        - label: Fire statements
          line: Magnesium metal is listed as a flammable solid (H228), as catching fire spontaneously if exposed to air (H250), and as releasing flammable gases on contact with water (H260, H261). Self-heating is also reported (H252).
        - label: Eyes
          line: Burning magnesium gives a bright white light with strong ultraviolet content, and the Goodfellow page says it can cause permanent eye damage on direct viewing.
    - title: If it fails
      lead: The routes to failure come from the fire data, the water reaction and the corrosion statements.
      points:
        - label: Ignition
          line: Ribbon ignites at about 650 degC (Goodfellow) and turnings at about 473 degC (PubChem). Finer forms ignite at lower temperatures.
        - label: Water
          line: Water releases flammable hydrogen gas and can ignite it. Water and carbon dioxide must not be used to fight a magnesium fire.
        - label: Chloride
          line: The passive film is disrupted by chloride. No pure-metal rate was read, so the corrosion rate of unprotected pure magnesium in salt water is not quantified here.
    - title: Handling and storage
      points:
        - label: Dry storage
          line: Keep the metal dry and sealed. Keep powder away from oxidisers, nitric acid and perchlorates, which PubChem lists as explosive or friction-sensitive mixtures with powdered magnesium.
        - label: Fire kit
          line: Keep dry sand, dry graphite or Met-L-X powder for a fire. The Goodfellow page names these as the extinguishing agents.
  why: 'Magnesium is the lightest common structural metal, at 1.74 g/cm3 at 20 degC (Goodfellow). It is the third most used structural metal after iron and aluminium (Wikipedia). Pure magnesium is weaker than its alloys: the Goodfellow page gives 140 to 160 MPa tensile strength for pure metal and 260 MPa for wrought AZ31. The pure metal matters where chemistry, not strength, decides the use: as the reducing metal for titanium (Kroll process), as a pyrotechnic and flare fuel, and as an anode material under research for magnesium-ion batteries. Most magnesium sold for structures is an alloy, such as the AZ31B covered in its own profile.'
  uses:
    - where: Electronics housings
      line: Goodfellow says a typical magnesium laptop shell weighs 30 to 40 percent less than an equivalent aluminium die-cast housing. The page's example is for magnesium alloys, not the pure metal.
    - where: Titanium and zirconium production
      line: Goodfellow says high-purity ingot of 99.8% or more is used in the Kroll process, which reduces titanium tetrachloride with magnesium in a sealed reactor.
    - where: Magnesium-ion battery research
      line: Goodfellow calls magnesium an emerging anode material for next-generation magnesium-ion batteries. The sources read do not show a commercial cell.
  can_do:
    - label: Weight
      value: 1.74 g/cm3
      line: Density is 1.74 g/cm3 at 20 degC (Goodfellow), and 1.738 g/cm3 at 20 degC in the Merck Index value that PubChem quotes.
      benchmark: density
    - label: Melting
      value: 650 degC
      line: Melting point is 650 degC (923 K) on the Goodfellow page. The metal must be melted under a cover gas, because molten magnesium ignites readily in air.
      benchmark: melting_point
    - label: Heat conduction
      value: 156 W/m·K
      line: Thermal conductivity is 156 W/m·K on the Goodfellow page, at a temperature the page does not state.
      benchmark: thermal_conductivity
    - label: Strength
      value: 140 to 160 MPa tensile
      line: Annealed pure magnesium is printed at 140 to 160 MPa tensile strength on the Goodfellow page. The same row gives 180 to 350 MPa for alloys.
      benchmark: ultimate_tensile_strength
  compare: Against its own alloy AZ31B, pure magnesium is less strong and more conductive. The Goodfellow page gives 140 to 160 MPa tensile strength for annealed pure metal and 260 MPa for wrought AZ31, and gives thermal conductivity of 156 W/m·K for pure magnesium. AZ31B is about 3 wt% aluminium and 1 wt% zinc, with magnesium as the balance (AircraftMaterials data sheet). Pure magnesium does not carry those additions, and its corrosion behaviour is set by the bare metal. The sources read do not give a corrosion rate for pure magnesium, so the corrosion comparison is qualitative.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Tensile strength
      benchmark: ultimate_tensile_strength
    - label: Thermal conductivity
      benchmark: thermal_conductivity
  handling:
    - Keep the metal dry. PubChem gives H261 (flammable gas on contact with water) in 44.8% of its reports for magnesium metal.
    - Keep dry sand, dry graphite or Met-L-X powder for a fire. Water and carbon dioxide cannot be used.
    - Keep powder away from oxidisers, nitric acid and perchlorates.
    - Melt and cast under a cover gas such as SF6 or CO2/SO2.
  good_for:
    - Titanium and zirconium reduction. Goodfellow sells 99.8% or higher ingot for the Kroll process.
    - Light metal where the pure metal is wanted for research on magnesium chemistry or magnesium-ion anodes.
  watch_out:
    - Fire. Ribbon ignites at about 650 degC and turnings at about 473 degC, and water and carbon dioxide do not put out the fire.
    - Chloride and galvanic contact. The Goodfellow page says galvanic corrosion with aluminium, steel or copper is severe unless parts are isolated.
    - Strength. Annealed pure metal is 140 to 160 MPa in tension, well below the 260 MPa printed for wrought AZ31.
  verdict: Pure magnesium is the lightest common metal and the usual reducing metal for titanium, but it is a weak, reactive metal in its bare form. For structures, use an alloy such as AZ31B with protection; use the pure metal where its chemistry is the point.