spore: profile
id: lithium-orthosilicate
spore_version: 0.2
family: lithium
name: Lithium orthosilicate
abbreviation: Li4SiO4
role: Ceramic tritium-breeder material and candidate lithium-ion conductor
category: energy
type: solid-state-batteries
summary: |
  Lithium orthosilicate (Li4SiO4) is a lithium-rich oxide ceramic that has a monoclinic structure up to its melting point. Hanaor et al. (2014) describe it as a leading candidate for tritium-breeding pebbles in the helium-cooled pebble bed blanket studied for ITER. Its melting point is printed as 1258 °C in the Wikipedia article and in the 2014 study, while two trade or supplier listings print 1255 °C and 1256 °C. Pebble crush tests and a high-temperature CO2 sorbent test are also reported. No space flight or vacuum data were found in the sources opened.
best_for: Tritium-breeding pebbles in helium-cooled pebble bed blankets, per Hanaor et al. (2014)
weakest_at: Crush strength of pebbles depends strongly on size and transparency (Annabattula et al.), and no pure-phase conductivity value could be recorded
identity:
  formula: Li4SiO4
  cas: 13453-84-4
  crystal_system: monoclinic
  source: hanaor2014
  where: 'Introduction: Li4SiO4 exists in a monoclinic structure up to temperatures of 1258 °C'
tags:
  environments: []
  stresses: []
  applications: []
properties:
  - benchmark: molar_mass
    label: Molar mass
    value: 119.84
    unit: g·mol−1
    scope: material
    conditions:
      formula: Li4SiO4
      cas: 13453-84-4
    method: Molar mass as printed in the infobox of the Wikipedia article on lithium orthosilicate
    status: calculated
    source: wikipedia-li4sio4
    where: Infobox, molar mass row
  - benchmark: melting_point
    label: Congruent melting temperature
    value: 1258
    unit: °C
    scope: material
    conditions:
      process: congruent melting, as the Wikipedia article describes it
    method: Melting temperature stated in the Wikipedia article text (printed as 1,258 °C)
    status: ground
    source: wikipedia-li4sio4
    where: Article text on melting behaviour
  - benchmark: melting_point
    label: Congruent melting temperature of monoclinic Li4SiO4
    value: 1258
    unit: °C
    scope: material
    conditions:
      phase: monoclinic Li4SiO4, melting congruently at this temperature
    method: Stated in the introduction of Hanaor et al. (2014)
    status: ground
    source: hanaor2014
    where: Introduction, paragraph on Li2TiO3 and Li4SiO4 phases
  - benchmark: melting_point
    label: Melting point, supplier SDS physical data
    value: 1255
    unit: °C
    scope: material
    conditions:
      grade: lithium orthosilicate, CAS 13453-84-4, as listed on the SDS page
    method: Physical data block on the ChemicalBook safety data sheet page
    status: ground
    note: Hanaor et al. (2014) cite earlier studies that describe a peritectic decomposition at 1255 °C rather than congruent melting.
    source: chemicalbook-li4sio4
    where: Physical data block
  - benchmark: melting_point
    label: Melting point, trade listing
    value: 1256
    unit: °C
    scope: material
    conditions:
      grade: industrial grade, 99.99% purity as listed
    method: Melting point on a trade listing for lithium orthosilicate (printed as 1256 Degree Celsius)
    status: ground
    note: A trade listing, not a test report.
    source: tradeindia-li4sio4
    where: Product specification list, melting point
  - benchmark: density
    label: Density, trade listing
    value: 2.39
    unit: g/cm3
    scope: material
    conditions:
      grade: industrial grade, white powder, 99.99% purity as listed
    method: Density on a trade listing for lithium orthosilicate (printed as 2.390)
    status: ground
    note: Trade listing only. No absolute density for pure Li4SiO4 from a peer-reviewed source was found in the sources opened.
    source: tradeindia-li4sio4
    where: Product specification list, density
  - benchmark: elastic_modulus
    label: Young's modulus of melt-spray pebble
    value: 90
    unit: GPa
    scope: material
    conditions:
      form: melt-spray pebbles of Li4SiO4 (OSi), 250 µm to 800 µm diameter in the study
    method: Value given as the pebble input to the contact analysis (Eq. 2); not measured in this paper
    status: ground
    source: annabattula2014
    where: Crush analysis section, text after Eq. 2 (E p = 90 GPa)
  - benchmark: poissons_ratio
    label: Poisson's ratio of melt-spray pebble
    value: 0.25
    unit: '-'
    scope: material
    conditions:
      form: same melt-spray pebbles as the Young's modulus row
    method: Value given as the pebble input to the contact analysis; not measured in this paper
    status: ground
    source: annabattula2014
    where: Crush analysis section, text after Eq. 2 (ν p = 0.25)
  - benchmark: critical_failure_energy
    label: Critical failure energy per unit area of melt-spray pebble
    value: 0.02
    unit: kJ/m2
    scope: material
    conditions:
      form: melt-spray pebble, fitted to crush-load data for a 500 µm pebble
    method: Value the authors assumed and fitted to crush-load data; not measured directly
    status: calculated
    source: annabattula2014
    where: Crush analysis section, text on critical failure energy (W c = 0.02 kJ/m2)
  - benchmark: co2_uptake
    label: CO2 uptake of sol-gel Li4SiO4 nanoparticle sorbent
    value: 6.9
    unit: mmol CO2/g sorbent
    scope: material
    conditions:
      temperature: 700 °C
      co2_pressure: 0.6 atm CO2
      measurement: thermogravimetric analysis
      form: sol-gel nanoparticles
    method: Uptake reported in the abstract of the 2017 sol-gel study (printed as 6.9 mmol of CO2/g sorbent)
    status: ground
    note: A result for a nanoparticle sorbent, not for the bulk powder.
    source: cet-sol-gel
    where: Abstract
  - benchmark: carbonation_conversion
    label: Conversion of lithium orthosilicate in CO2 sorbent test
    value: 82.4
    unit: '%'
    scope: material
    conditions:
      temperature: 700 °C
      co2_pressure: 0.6 atm CO2
      form: sol-gel nanoparticles
    method: Conversion reported in the abstract of the sol-gel study
    status: ground
    note: A sorbent result for nanoparticles.
    source: cet-sol-gel
    where: Abstract
  - benchmark: purity
    label: Purity, industrial grade listing
    value: 99.99
    unit: '%'
    scope: material
    conditions:
      grade: industrial grade, as listed
    method: Purity stated in the product title of a trade listing
    status: ground
    note: Listing specification, not a measured value.
    source: tradeindia-li4sio4
    where: Product title
corrosion: []
risks:
  hazards:
    - text: Harmful if swallowed (H302, signal word Warning) on the ChemicalBook SDS page. The same page lists skin irritation (H315), serious eye irritation (H319) and possible respiratory irritation (H335) in its full hazard list.
      ghs:
        - H302
        - H315
        - H319
        - H335
      source: chemicalbook-li4sio4
      where: GHS hazard statements, Section 2 (H302) and Section 16 (H315, H319, H335)
  failure_risks:
    - mode: Lithium loss from the silicate during high-temperature firing
      trigger: Firing above 800 °C in the synthesis of lithium-bearing ceramic breeder materials
      consequence: The abstract ties a lithium deficiency in the region of 5% to lithium sublimation from Li4SiO4, and the results describe lithium loss during firing, particularly above 800 °C.
      severity: moderate
      source: hanaor2014
      where: Abstract; results on lithium loss during firing
    - mode: Pebble crushing with size-dependent strength
      trigger: Uniaxial compression of melt-spray pebbles of 250 µm to 800 µm diameter
      consequence: Transparent pebbles fail at much lower load than opaque ones, and voids left during solidification lower the mechanical strength of the pebble.
      severity: moderate
      source: annabattula2014
      where: 'Results: crush load versus pebble size and failure regions A to C'
  handling:
    - text: Avoid contact with skin and eyes and avoid forming dust and aerosols (ChemicalBook SDS, Section 7).
      source: chemicalbook-li4sio4
      where: Handling and storage, Section 7
    - text: Keep in a dry area at room temperature (ChemicalBook SDS, Section 7).
      source: chemicalbook-li4sio4
      where: Handling and storage, Section 7
  mitigations:
    - text: Store the powder dry and keep the container closed, as the SDS advises.
      source: chemicalbook-li4sio4
      where: Handling and storage, Section 7
uses:
  - application: radiation-shielding
    device: Tritium-breeding pebble bed in a helium-cooled blanket (ITER concept)
    example: Hanaor et al. (2014) describe Li4SiO4 and Li2TiO3 as leading candidate materials for tritium-breeding pebbles in the helium-cooled pebble bed concept. The source describes tritium breeding, not shielding; the application slug is the nearest in the site list.
    source: hanaor2014
    where: Introduction, first two paragraphs
  - application: batteries
    device: Lithium-ion conductor additive in a sulfide solid electrolyte (Li7P2S8I)
    example: Adding 10 mol% Li4SiO4 raised the room-temperature ionic conductivity of Li7P2S8I to 0.85 mS cm−1, compared with 0.35 mS cm−1 for the undoped sulfide, in samples made by liquid-phase shaking. This is a composite result, not a value for pure Li4SiO4.
    source: pmc-li7p2s8i
    where: Abstract and results; liquid-phase shaking samples at x = 0 and x = 10
supply:
  - subject: Lithium
    producers:
      - country: Australia
        year: 2025
      - country: China
        year: 2025
      - country: Chile
        year: 2025
      - country: Zimbabwe
        year: 2025
      - country: Argentina
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals (Lithium, used in rechargeable batteries)
        listed: true
    recycling: 'USGS: construction of lithium battery recycling plants continued throughout 2025.'
    substitutes:
      - 'USGS: substitution for lithium compounds is possible in batteries, ceramics, greases, and manufactured glass.'
    source: usgs-mcs2026-lithium
    where: 'World Mine Production and Reserves table, 2025 column (Australia 92,000 t, China 62,000 t, Chile 56,000 t, Zimbabwe 28,000 t, Argentina 23,000 t, world total 290,000 t). Shares are not printed and are not recorded here. Critical list: USGS final 2025 list page.'
  - subject: Silicon
    producers:
      - country: China
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals (Silicon, used in silicon wafers fundamental to semiconductors)
        listed: true
    recycling: 'USGS silicon chapter: recycling is insignificant.'
    substitutes:
      - 'USGS: gallium arsenide and germanium are the principal substitutes for silicon in semiconductor and infrared applications.'
    source: usgs-mcs2026-silicon
    where: 'Events, Trends and Issues: China accounted for almost 80% of total global estimated production of silicon materials in 2025. The chapter covers ferrosilicon and silicon metal, not the silica or TEOS precursors used in sol-gel synthesis.'
sources:
  wikipedia-li4sio4:
    title: Lithium orthosilicate (Wikipedia article)
    id: CAS 13453-84-4
    url: https://en.wikipedia.org/wiki/Lithium_orthosilicate
    kind: web
  chemicalbook-li4sio4:
    title: 'ChemicalBook: Lithium orthosilicate, safety data sheet and physical data'
    id: CAS 13453-84-4
    url: https://www.chemicalbook.com/msds/lithiumorthosilicate.htm
    kind: datasheet
  tradeindia-li4sio4:
    title: 'TradeIndia: Lithium Orthosilicate, CAS 13453-84-4, product listing'
    id: CAS 13453-84-4
    url: https://www.tradeindia.com/products/lithium-orthosilicate-cas-13453-84-4-8480708.html
    kind: web
  hanaor2014:
    title: Solution based synthesis of mixed-phase materials in the Li2TiO3-Li4SiO4 system
    id: Hanaor, Kolb, Gan, Kamlah, Knitter; J. Nucl. Mater. 456 (2014) 151-161; arXiv:1410.7128
    url: https://arxiv.org/pdf/1410.7128
    year: 2014
    kind: paper
  annabattula2014:
    title: Size dependent crush analysis of lithium orthosilicate pebbles
    id: Annabattula, Kolb, Gan, Rolli, Kamlah; arXiv:1408.0485
    url: https://arxiv.org/pdf/1408.0485
    year: 2014
    kind: paper
  cet-sol-gel:
    title: Sol-gel Synthesis of Li4SiO4 Nanoparticles for CO2 Capture at High Temperature (Chemical Engineering Transactions)
    id: Chemical Engineering Transactions, article 2255
    url: https://cetjournal.it/index.php/cet/article/view/2255
    kind: paper
  pmc-li7p2s8i:
    title: Li4SiO4 Doped-Li7P2S8I solid electrolytes with high lithium stability synthesised using liquid-phase shaking
    id: PMC8982210; Royal Society of Chemistry
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC8982210
    kind: paper
  usgs-mcs2026-lithium:
    title: Mineral Commodity Summaries 2026, Lithium
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-lithium.pdf
    year: 2026
    kind: report
  usgs-mcs2026-silicon:
    title: Mineral Commodity Summaries 2026, Silicon
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf
    year: 2026
    kind: report
  usgs-crit2025:
    title: About the 2025 List of Critical Minerals (USGS)
    id: Final 2025 List of Critical Minerals
    url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
    year: 2025
    kind: web
documents:
  - title: 'ChemicalBook: lithium orthosilicate safety data sheet and physical data'
    type: sds
    url: https://www.chemicalbook.com/msds/lithiumorthosilicate.htm
  - title: 'TradeIndia: lithium orthosilicate product listing'
    type: datasheet
    url: https://www.tradeindia.com/products/lithium-orthosilicate-cas-13453-84-4-8480708.html
  - title: Hanaor et al., Solution based synthesis of mixed-phase materials in the Li2TiO3-Li4SiO4 system (arXiv:1410.7128)
    type: paper
    url: https://arxiv.org/pdf/1410.7128
    year: 2014
  - title: Annabattula et al., Size dependent crush analysis of lithium orthosilicate pebbles (arXiv:1408.0485)
    type: paper
    url: https://arxiv.org/pdf/1408.0485
    year: 2014
  - title: Sol-gel Synthesis of Li4SiO4 Nanoparticles for CO2 Capture at High Temperature (Chemical Engineering Transactions, article 2255)
    type: paper
    url: https://cetjournal.it/index.php/cet/article/view/2255
  - title: Li4SiO4 Doped-Li7P2S8I solid electrolytes (PMC8982210)
    type: paper
    url: https://pmc.ncbi.nlm.nih.gov/articles/PMC8982210
  - title: 'USGS Mineral Commodity Summaries 2026: Lithium'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-lithium.pdf
    year: 2026
  - title: 'USGS Mineral Commodity Summaries 2026: Silicon'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-silicon.pdf
    year: 2026
gaps:
  - No thermal conductivity, specific heat or thermal expansion value for pure Li4SiO4 was found in the sources opened. The Springer (Journal of Advanced Ceramics) and MDPI pages were blocked or redirected to a login.
  - The Pisa 2021 Fusion Engineering and Design paper on Li4SiO4 pebble mechanics could not be opened; only its landing page was readable.
  - No peer-reviewed absolute density for pure Li4SiO4 was found. The only density (2.39 g/cm3) is from a trade listing. A ChemicalBook relative density of 2.326 has no printed unit, so it is left out.
  - 'Melting point differs between sources: 1258 °C (Wikipedia and Hanaor et al.), 1255 °C (ChemicalBook SDS and an earlier peritectic report), 1256 °C (trade listing). All are recorded side by side.'
  - No crystal space group or lattice parameters were found. Only the monoclinic description is recorded.
  - 'Ionic conductivity of pure Li4SiO4 was not recorded: the values found in the literature are printed in scientific notation (exponent form), which the verification step cannot match, so they were left out. The only conductivity recorded is for a Li7P2S8I composite.'
  - Molecular weight is printed without a unit on the ChemicalBook and trade pages (119.85), so those rows are left out. Only the Wikipedia molar mass (119.84 g·mol−1) is recorded.
  - The site's application list has no fusion-breeding or CO2-capture slug. The fusion use is recorded under radiation-shielding, the nearest slug, and the source describes tritium breeding, not shielding. The CO2 result is in the properties and story, not in uses.
  - Hazard data rest on one supplier SDS (ChemicalBook). The American Elements SDS and the PubChem GHS page could not be read (403 and reCAPTCHA), so the hazard classification could not be cross-checked.
  - No corrosion, humidity or ageing data for Li4SiO4 were found in any source opened.
  - Crustal abundance of silicon or lithium in the Earth's crust was not sourced in this run. Producer shares are not printed in the USGS tables, so none are recorded.
  - Silicon producers are given only as China (almost 80% of global silicon materials production, USGS). The silicon chapter does not cover the silica or TEOS precursors used in sol-gel synthesis.
  - The CO2 uptake (6.9 mmol CO2/g sorbent) and 82.4 % conversion are for a nanoparticle sorbent at 700 °C and 0.6 atm CO2. Whether the full text is open access was not confirmed.
  - Property names molar_mass, co2_uptake, carbonation_conversion and critical_failure_energy are not in the canonical list in spores/property-canon.yaml; they are short snake_case names used here.
  - Purity (99.99 %) is a listing specification from a trade seller, not a measured value.
license: CC-BY-4.0
updated: '2026-11-01'
review:
  status: draft
  method: assistant
  checked_values: 12
  note: Written by an AI assistant on 2026-11-01 from pages opened in this run. Values were checked against their cited pages with scripts/verify-values.mjs; see the gate results in the run log.
story:
  recipe:
    line: 'Lithium orthosilicate has the formula Li4SiO4: four lithium atoms, one silicon atom and four oxygen atoms per formula unit (Wikipedia). Hanaor et al. (2014) describe solution-based routes to the silicate and its mixtures with Li2TiO3. The 2017 CO2 sorbent study made Li4SiO4 nanoparticles by a sol-gel route.'
    parts:
      - name: Lithium
        symbol: Li
        role: 'Lithium-bearing breeder: the source describes lithium-bearing ceramic pebbles for tritium breeding.'
      - name: Silicon
        symbol: Si
        role: The network-forming element of the silicate. Hanaor et al. use tetraethyl orthosilicate as a silicon precursor in their sol-gel work.
      - name: Oxygen
        symbol: O
        role: Oxygen forms the SiO4 unit that the silicate is built from.
  risk_groups:
    - title: For people
      level: 0
      verdict: Harmful if swallowed; irritant
      lead: The supplier SDS classifies lithium orthosilicate as harmful if swallowed and as an irritant (H302, H315, H319, H335).
      points:
        - label: Swallowing
          line: The SDS lists H302, harmful if swallowed, and advises calling a poison centre or doctor if you feel unwell.
        - label: Skin and eyes
          line: H315 causes skin irritation and H319 causes serious eye irritation. The SDS advises washing with soap and water and rinsing the eyes thoroughly.
        - label: Dust
          line: Avoid forming dust and aerosols, and avoid contact with skin and eyes.
    - title: In service
      lead: These results come from firing tests and pebble tests in the laboratory, not from field incidents.
      points:
        - label: Lithium loss
          line: Lithium sublimes during high-temperature firing, particularly above 800 °C. The abstract ties a lithium deficiency in the region of 5% to this loss.
        - label: Pebble strength
          line: Melt-spray pebbles of 250 µm to 800 µm were crush-tested. Transparent pebbles fail at much lower load than opaque ones.
    - title: Handling and storage
      points:
        - label: Storage
          line: Keep the powder in a dry area at room temperature, and keep the container closed.
        - label: Dust
          line: Avoid forming dust and aerosols.
  why: 'Lithium orthosilicate (Li4SiO4) is a lithium-rich oxide ceramic. Hanaor et al. (2014) describe it as a leading candidate for tritium-breeding pebbles in the helium-cooled pebble bed concept, which is studied for the ITER breeding blanket. Its melting point is printed as 1258 °C in the Wikipedia article and in the 2014 study. The same material also absorbs CO2 at high temperature: a 2017 sol-gel study reports 6.9 mmol CO2/g sorbent at 700 °C.'
  uses:
    - where: Fusion breeder blankets
      line: Hanaor et al. (2014) describe Li4SiO4 and Li2TiO3 as leading candidate materials for tritium-breeding pebbles in the helium-cooled pebble bed concept. The source describes tritium breeding, not shielding.
    - where: Solid electrolyte additive
      line: In a sulfide solid electrolyte, adding 10 mol% Li4SiO4 raised the room-temperature ionic conductivity of Li7P2S8I to 0.85 mS cm−1, from 0.35 mS cm−1 without it. This is a composite result, not a value for pure Li4SiO4.
  can_do:
    - label: CO2 capture
      value: 6.9 mmol CO2/g sorbent
      line: 'Absorbs CO2 at high temperature: 6.9 mmol CO2 per gram of sorbent at 700 °C and 0.6 atm CO2 in a sol-gel nanoparticle study, with 82.4 % conversion.'
    - label: Fusion breeding
      line: Serves as a candidate tritium-breeding pebble in a helium-cooled pebble bed blanket, per Hanaor et al. (2014).
    - label: Melting point
      value: 1255 to 1258 °C
      line: Melts at 1255 to 1258 °C, depending on the source. Wikipedia and the 2014 study print 1258 °C.
    - label: Pebble stiffness
      value: 90 GPa
      line: 'Carries a load as pebbles: the crush analysis uses a Young''s modulus of 90 GPa and a Poisson''s ratio of 0.25 for the pebble.'
  compare: Hanaor et al. (2014) describe Li4SiO4 and Li2TiO3 as the two leading candidates for tritium-breeding pebbles. They report that Li2TiO3 melts congruently, while Li4SiO4 melts congruently at 1258 °C. The two form a quasi-binary system, so pebbles of mixed composition are studied as well. The table compares the melting point, density and pebble stiffness recorded for Li4SiO4.
  compare_rows:
    - label: Melting point
      benchmark: melting_point
    - label: Density
      benchmark: density
    - label: Young's modulus of pebble
      benchmark: elastic_modulus
  handling:
    - Keep the powder dry and at room temperature, as the SDS advises.
    - Avoid contact with skin and eyes, and avoid forming dust.
    - Treat the powder as harmful if swallowed, per the SDS classification.
  good_for:
    - Tritium breeding research. Hanaor et al. (2014) describe it as a leading candidate for helium-cooled pebble bed blankets.
    - 'High-temperature CO2 capture in a laboratory sorbent test: 6.9 mmol CO2/g sorbent at 700 °C.'
  watch_out:
    - 'Melting point differs between sources: 1255 °C, 1256 °C and 1258 °C.'
    - Pebble strength depends on size and transparency. Transparent pebbles fail at much lower load (Annabattula et al.).
    - The density figure comes from a trade listing, and no pure-phase conductivity value could be recorded.
  verdict: Li4SiO4 is a well-studied breeder ceramic with melting data from three sources. Its density and hazard classification rest on thin sources, and the gaps are listed.