Lithium orthosilicate Li4SiO4
Li4SiO4 · CAS 13453-84-4 · monoclinic
Lithium orthosilicate (Li4SiO4) is a lithium-rich oxide ceramic that has a monoclinic structure up to its melting point.
Evidence level
2 of 5
Lab-measured
- 0Predicted only. No one has made it, or no measurement exists.
- 1Calculated. Only calculated or predicted values from sources.
- 2Lab-measured. Measured properties with their conditions stated.
- 3Space-relevant tests. Measured in conditions relevant to space, such as vacuum or atomic oxygen.
- 4Ground-qualified. Qualified for an application on the ground.
- 5Flown or field-proven. Flight or field results exist.
CO2 capture
6.9 mmol CO2/g sorbent
Melting point
1255 to 1258 °C
Pebble stiffness
90 GPa
Recipe, share of the weight
- Li not statedLithium
- Si not statedSilicon
- O not statedOxygen
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
Risk at a glance
- People None found. Harmful if swallowed; irritant
- If it fails Moderate. Lithium loss from the silicate during high-temperature firing
- Corrosion No data. No corrosion data recorded
Quick facts: Li4SiO4
| Property | Value | Basis |
|---|---|---|
| Density | 2.39 g/cm³ | 1 sourced value |
| Young's modulus | 90 GPa | 1 sourced value |
| Melting point | 1,255 to 1,258 °C | 4 sourced values across conditions |
What is the density of Lithium orthosilicate (Li4SiO4)?
Lithium orthosilicate (Li4SiO4) has a density of 2.39 g/cm³. The source and test conditions are listed in the properties table on this page.
What is the melting point of Lithium orthosilicate (Li4SiO4)?
Lithium orthosilicate (Li4SiO4) has a melting point of 1,255 to 1,258 °C. The range covers 4 sourced values across the tempers, forms and test conditions the sources report; room-temperature values are used where a source states a temperature.
What is the Young's modulus of Lithium orthosilicate (Li4SiO4)?
Lithium orthosilicate (Li4SiO4) has a Young's modulus of 90 GPa. The source and test conditions are listed in the properties table on this page.
What is Lithium orthosilicate (Li4SiO4) used for?
Uses recorded in the sources include Tritium-breeding pebble bed in a helium-cooled blanket (ITER concept); Lithium-ion conductor additive in a sulfide solid electrolyte (Li7P2S8I).
Why it exists
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.
Where it's used
Fusion breeder blankets
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.
Solid electrolyte additive
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.
Recipe
Li4SiO4
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.
| Ingredient | Share of the weight | What it does |
|---|---|---|
| Lithium Li | not stated | Lithium-bearing breeder: the source describes lithium-bearing ceramic pebbles for tritium breeding. |
| Silicon Si | not stated | The network-forming element of the silicate. Hanaor et al. use tetraethyl orthosilicate as a silicon precursor in their sol-gel work. |
| Oxygen O | not stated | Oxygen forms the SiO4 unit that the silicate is built from. |
Weight shares are as printed in the sources.
What it can do
CO2 capture
6.9 mmol CO2/g sorbent
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.
Fusion breeding
Serves as a candidate tritium-breeding pebble in a helium-cooled pebble bed blanket, per Hanaor et al. (2014).
Melting point
1255 to 1258 °C
Melts at 1255 to 1258 °C, depending on the source. Wikipedia and the 2014 study print 1258 °C.
Pebble stiffness
90 GPa
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.
How it compares
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.
The same measurements for each material, so you can compare them. Each row names the key condition under the value; the full conditions and methods are in the numbered notes under Technical details. Compare every grade in the family.
| Measurement | Li4SiO4 |
|---|---|
| Capacity and energy | |
| Critical failure energy per unit area of melt-spray pebble | 0.02 kJ/m29 |
| Thermal behavior and safety | |
| Congruent melting temperature | 1258 °C2 |
| Congruent melting temperature of monoclinic Li4SiO4 | 1258 °C3 |
| Melting point, supplier SDS physical data | 1255 °C4 |
| Melting point, trade listing | 1256 °C5 |
| CO2 uptake of sol-gel Li4SiO4 nanoparticle sorbent | 6.9 mmol CO2/g sorbent10 |
| Physical and electrical | |
| Density, trade listing | 2.39 g/cm³6 |
| Other measurements | |
| Molar mass | 119.8 g·mol−11 |
| Young's modulus of melt-spray pebble | 90 GPa7 |
| Poisson's ratio of melt-spray pebble | 0.25 -8 |
| Conversion of lithium orthosilicate in CO2 sorbent test | 82.4 %11 |
| Purity, industrial grade listing | 99.99 %12 |
Why choose it, and why not
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 for
- 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.
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.
Technical details
For scientists and researchers. Everything above comes from the record below: every number with its method, its conditions and its source.
Notes
The method, full conditions and any caveat for the numbered rows above.
| # | Measurement | Method | Conditions | Caveat |
|---|---|---|---|---|
| 1 | Molar mass | Molar mass as printed in the infobox of the Wikipedia article on lithium orthosilicate | formula Li4SiO4cas 13453-84-4 | — |
| 2 | Congruent melting temperature | Melting temperature stated in the Wikipedia article text (printed as 1,258 °C) | process congruent melting, as the Wikipedia article describes it | — |
| 3 | Congruent melting temperature of monoclinic Li4SiO4 | Stated in the introduction of Hanaor et al. (2014) | phase monoclinic Li4SiO4, melting congruently at this temperature | — |
| 4 | Melting point, supplier SDS physical data | Physical data block on the ChemicalBook safety data sheet page | grade lithium orthosilicate, CAS 13453-84-4, as listed on the SDS page | Hanaor et al. (2014) cite earlier studies that describe a peritectic decomposition at 1255 °C rather than congruent melting. |
| 5 | Melting point, trade listing | Melting point on a trade listing for lithium orthosilicate (printed as 1256 Degree Celsius) | grade industrial grade, 99.99% purity as listed | A trade listing, not a test report. |
| 6 | Density, trade listing | Density on a trade listing for lithium orthosilicate (printed as 2.390) | grade industrial grade, white powder, 99.99% purity as listed | Trade listing only. No absolute density for pure Li4SiO4 from a peer-reviewed source was found in the sources opened. |
| 7 | Young's modulus of melt-spray pebble | Value given as the pebble input to the contact analysis (Eq. 2); not measured in this paper | form melt-spray pebbles of Li4SiO4 (OSi), 250 µm to 800 µm diameter in the study | — |
| 8 | Poisson's ratio of melt-spray pebble | Value given as the pebble input to the contact analysis; not measured in this paper | form same melt-spray pebbles as the Young's modulus row | — |
| 9 | Critical failure energy per unit area of melt-spray pebble | Value the authors assumed and fitted to crush-load data; not measured directly | form melt-spray pebble, fitted to crush-load data for a 500 µm pebble | — |
| 10 | CO2 uptake of sol-gel Li4SiO4 nanoparticle sorbent | Uptake reported in the abstract of the 2017 sol-gel study (printed as 6.9 mmol of CO2/g sorbent) | temperature 700 °Cco2 pressure 0.6 atm CO2measurement thermogravimetric analysisform sol-gel nanoparticles | A result for a nanoparticle sorbent, not for the bulk powder. |
| 11 | Conversion of lithium orthosilicate in CO2 sorbent test | Conversion reported in the abstract of the sol-gel study | temperature 700 °Cco2 pressure 0.6 atm CO2form sol-gel nanoparticles | A sorbent result for nanoparticles. |
| 12 | Purity, industrial grade listing | Purity stated in the product title of a trade listing | grade industrial grade, as listed | Listing specification, not a measured value. |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The supplier SDS classifies lithium orthosilicate as harmful if swallowed and as an irritant (H302, H315, H319, H335).
- Swallowing
- The SDS lists H302, harmful if swallowed, and advises calling a poison centre or doctor if you feel unwell.
- Skin and eyes
- H315 causes skin irritation and H319 causes serious eye irritation. The SDS advises washing with soap and water and rinsing the eyes thoroughly.
- Dust
- Avoid forming dust and aerosols, and avoid contact with skin and eyes.
In service
These results come from firing tests and pebble tests in the laboratory, not from field incidents.
- Lithium loss
- Lithium sublimes during high-temperature firing, particularly above 800 °C. The abstract ties a lithium deficiency in the region of 5% to this loss.
- Pebble strength
- Melt-spray pebbles of 250 µm to 800 µm were crush-tested. Transparent pebbles fail at much lower load than opaque ones.
Handling and storage
- Storage
- Keep the powder in a dry area at room temperature, and keep the container closed.
- Dust
- Avoid forming dust and aerosols.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Lithium loss from the silicate during high-temperature firingmoderate severity | Firing above 800 °C in the synthesis of lithium-bearing ceramic breeder materialsThe 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. |
| Pebble crushing with size-dependent strengthmoderate severity | Uniaxial compression of melt-spray pebbles of 250 µm to 800 µm diameterTransparent pebbles fail at much lower load than opaque ones, and voids left during solidification lower the mechanical strength of the pebble. |
Handling and storage
- Avoid contact with skin and eyes and avoid forming dust and aerosols (ChemicalBook SDS, Section 7).
- Keep in a dry area at room temperature (ChemicalBook SDS, Section 7).
Mitigations
- Store the powder dry and keep the container closed, as the SDS advises.
Supply and geography
How common the raw materials are and where they come from.
Lithium
- Top producers (2025)
- Australia, China, Chile, Zimbabwe, Argentina
- Critical mineral lists
- US: listed
- 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.
Silicon
- Top producers (2025)
- China
- Critical mineral lists
- US: listed
- Recycling
- USGS silicon chapter: recycling is insignificant.
- Substitutes
- USGS: gallium arsenide and germanium are the principal substitutes for silicon in semiconductor and infrared applications.
Documents
Datasheets, safety data sheets, papers and standards you can open.
Full record
The complete spore, as stored. Free to reuse under CC-BY-4.0. Images keep the licence shown with each one.
Show the full YAML
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.
References
Every number above carries a reference number. Click one to see the source and where in it the value comes from.
| # | Source | Type | Year | Used for |
|---|---|---|---|---|
| Lithium orthosilicate (Wikipedia article) | web | 2 values | ||
| ChemicalBook: Lithium orthosilicate, safety data sheet and physical data | datasheet | 5 values | ||
| TradeIndia: Lithium Orthosilicate, CAS 13453-84-4, product listing | web | 3 values | ||
| Solution based synthesis of mixed-phase materials in the Li2TiO3-Li4SiO4 system | paper | 2014 | 4 values | |
| Size dependent crush analysis of lithium orthosilicate pebbles | paper | 2014 | 4 values | |
| Sol-gel Synthesis of Li4SiO4 Nanoparticles for CO2 Capture at High Temperature (Chemical Engineering Transactions) | paper | 2 values | ||
| Li4SiO4 Doped-Li7P2S8I solid electrolytes with high lithium stability synthesised using liquid-phase shaking | paper | 1 value | ||
| Mineral Commodity Summaries 2026, Lithium | report | 2026 | 1 value | |
| Mineral Commodity Summaries 2026, Silicon | report | 2026 | 1 value | |
| About the 2025 List of Critical Minerals (USGS) | web | 2025 | 0 values |