Cerium Ce
Ce (element, atomic number 58, USGS PP 1802-A periodic table) · CAS 7440-45-1
Cerium is the element Ce, a gray metal of the lanthanide series with a density of 6.77 g/cm3 and a melting point of 798 °C (Ames Laboratory SDS).
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.
Density
6.77 g/cm3
Melting
798 °C
Strength as rolled
102 MPa
Abundance
66.5 ppm
Recipe, share of the weight
- Ce 100.0%Cerium
Best for
Ceria (cerium oxide) as a UV-blocking, radiation-resistant dopant in solar-cell cover glass (NASA 1973 laboratory test)
Weakest at
Handling: finely divided metal is pyrophoric, and the metal reacts with water and moist air (Ames SDS, CAMEO)
Risk at a glance
- People Low. Flammable solid, category 1
- If it fails Severe. Ignition by friction or in fire
- Corrosion Severe. Cerium is readily oxidized by moist air and reacts vigorously with water, liberating flammable hydrogen.
Quick facts: Ce
| Property | Value | Basis |
|---|---|---|
| Density | 6.75 to 6.77 g/cm³ | 2 sourced values across conditions |
| Yield strength | 91 MPa | 1 sourced value |
| Tensile strength | 102 MPa | 1 sourced value |
| Thermal conductivity | 11.3 W/(m·K) | 1 sourced value |
| Thermal expansion (CTE) | 8 ppm/K | 1 sourced value |
| Melting point | 798 to 799 °C | 2 sourced values across conditions |
| Specific heat | 205 J/(kg·K) | 1 sourced value |
| Electrical resistivity | 8.5e-7 Ω·m | 1 sourced value |
What is the density of Cerium?
Cerium has a density of 6.75 to 6.77 g/cm³. The range covers 2 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 thermal conductivity of Cerium?
Cerium has a thermal conductivity of 11.3 W/(m·K). The source and test conditions are listed in the properties table on this page.
What is the coefficient of thermal expansion of Cerium?
Cerium has a coefficient of thermal expansion of 8 ppm/K. The source and test conditions are listed in the properties table on this page.
What is the melting point of Cerium?
Cerium has a melting point of 798 to 799 °C. The range covers 2 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 yield strength of Cerium?
Cerium has a yield strength of 91 MPa. The source and test conditions are listed in the properties table on this page.
What is Cerium used for?
Uses recorded in the sources include Solar-cell cover glass made from 1.5% ceria-doped Micro-Sheet (cerium oxide dopant); Metal alloys containing cerium, including mischmetal.
Why it exists
Cerium is a reactive rare-earth metal. The SDS treats it as a flammable solid, so the metal is handled under argon and kept away from water. Its main uses in this profile are not as the metal: NASA tested cerium oxide (ceria) as a dopant in solar-cell cover glass in 1973, and it resisted radiation-induced discoloration. PubChem says the metal goes into alloys, polishing agents and glass, and into mischmetal flints for cigarette lighters. Cerium was first identified in 1803.
Where it's used
Solar-cell cover glass
In the 1973 NASA Langley test, 1.5% ceria-doped cover glass was much less sensitive to electron-induced discoloration than undoped glass, and the report calls it comparable to synthetic fused silica. It was a laboratory test, not a flight result.
Alloys and lighter flints
PubChem, citing Ullmann, says cerium is used in metal alloys, polishing agents and glass, and that mischmetal makes flints for cigarette lighters. The source names no aerospace alloy.
Recipe
Ce (element, atomic number 58, USGS PP 1802-A periodic table)
Cerium is a single-element metal (Ce). It is not alloyed in the profile. Its ores are the minerals of the bastnaesite and monazite groups (Wikipedia); USGS reports bastnaesite mined at Mountain Pass, California, and monazite produced from heavy-mineral-sand concentrates in the southeastern United States. No source read gives the reduction process.
| Ingredient | Atoms per unit | Share of the weight | What it does |
|---|---|---|---|
| Cerium Ce | 1 | 100.0% | The whole material. The Ames SDS lists cerium at 100 % in section 3 (ingot, pieces, rod, foil, sheet and target), and the Goodfellow foil is 90 % purity. |
Weight shares are calculated from standard atomic weights.
What it can do
Density
6.77 g/cm3
measured
The Ames Laboratory SDS gives a relative density of 6.77 g/cc. Goodfellow's 90 % foil gives 6.75 g/cm3 at 20 °C.
Melting
798 °C
measured
The Ames SDS gives a melting point of 798 °C, and Goodfellow's foil gives 799 °C.
Strength as rolled
102 MPa
Goodfellow's 90 % purity foil, as rolled, gives 102 MPa tensile and 91 MPa yield. The datasheet does not say whether these are minimum values.
Abundance
66.5 ppm
USGS PP 1802-A gives cerium a crustal abundance of 66.5 ppm.
How it compares
Cerium is a reactive metal rather than a structural one. Its SDS treats it as a flammable solid, and it reacts with water and moist air, which sets it apart from the other metals in this collection. Its space record is as an oxide, ceria, in glass rather than as the metal. This profile has no other metal read in the same run, so the compare rows below give cerium's own values only.
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. Other materials are shown beside it; each was measured under its own conditions, so open its page before comparing closely. Compare every grade in the family.
| Measurement | Ce | Nd | Dy | Gd | La | Pr | Sm | Eu | Tb | Ho | Er | Tm | Yb | Lu | Y | Sc |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Thermal behavior and safety | ||||||||||||||||
| Melting point, cerium (Ames Laboratory SDS)Value printed in a safety data sheet | 798 °C | 1022 °C | 1412 °C | 1313 °C | 920 °C | 931 °C | 1072 °C | 826 °C | 1356 °C | 1461 °C | 1529 °C | 1545 °C | 819 °C | 1663 °C | 1526 °C | 1541 °C |
| Melting point, cerium foil (Goodfellow) | 799 °C3 | 1022 °C | 1412 °C | 1313 °C | 920 °C | 931 °C | 1072 °C | 826 °C | 1356 °C | 1461 °C | 1529 °C | 1545 °C | 819 °C | 1663 °C | 1526 °C | 1541 °C |
| Specific heat capacity, cerium foil (Goodfellow) | 205 J/(kg·K)5 | 190.3 J/(kg·K) | no data | 230 J/(kg·K) | 195.2 J/(kg·K) | 193 J/(kg·K) | no data | no data | 181.9 J/(kg·K) | 164.6 J/(kg·K) | no data | 160 J/(kg·K) | 145 J/(kg·K) | 155 J/(kg·K) | 298.4 J/(kg·K) | 567.7 J/(kg·K) |
| Thermal conductivity, cerium foil (Goodfellow) | 11.3 W/(m·K)6 | 16.5 W/(m·K) | 11 W/(m·K) | 10.5 W/(m·K) | 13.4 W/(m·K) | 12.5 W/(m·K) | 13 W m-1 K-1 | 13.9 W/(m·K) | 11.1 W/(m·K) | 16.2 W/(m·K) | 14.5 W/(m⋅K) | 17 W/(m·K) | 32.9 W/(m·K) | 16.4 W/(m·K) | 17.2 W/(m·K) | 15.8 W/(m·K) |
| Physical and electrical | ||||||||||||||||
| Density, cerium (Ames Laboratory SDS) | 6.77 g/cm³1 | 7.007 g/cm³ | 8.55 g/cm³ | 7.895 g/cm³ | 6.145 g/cm³ | 6.773 g/cm³ | 7353 kg/m3 | 5.264 g/cm³ | 8.229 g/cm³ | 8.795 g/cm³ | 9.065 g/cm³ | 9.321 g/cm³ | 6.977 g/cm³ | 9.842 g/cm³ | 4.469 g/cm³ | 2.989 g/cm³ |
| Density, cerium foil (Goodfellow) | 6.75 g/cm³2 | 7.007 g/cm³ | 8.55 g/cm³ | 7.895 g/cm³ | 6.145 g/cm³ | 6.773 g/cm³ | 7353 kg/m3 | 5.264 g/cm³ | 8.229 g/cm³ | 8.795 g/cm³ | 9.065 g/cm³ | 9.321 g/cm³ | 6.977 g/cm³ | 9.842 g/cm³ | 4.469 g/cm³ | 2.989 g/cm³ |
| Electrical resistivity, cerium foil (Goodfellow) | 85.4 µOhm·cm8 | 643 nΩ·m | no data | 134 µOhm·cm | 615 nΩ·m | 0.7 µΩ·m | 94 µΩ cm | 920 nΩ·m | 1.15 µΩ·m | 814 nΩ·m | 0.86 µΩ⋅m | 142 nΩ·m | 28 µOhm·cm | 68 µΩ·cm | 596 nΩ·m | 562 nΩ·m |
| Vickers hardness, cerium foil (Goodfellow) | 25 to 30 kgf/mm29 | 345 to 745 MPa | 540 MPa | 570 MPa | 491 MPa | 250 MPa | no data | 167 MPa | 863 MPa | 410 to 600 MPa | 430 MPa | 520 MPa | 206 MPa | 85 kgf/mm2 | no data | no data |
| Other measurements | ||||||||||||||||
| Boiling point, cerium (Ames Laboratory SDS)Value printed in a safety data sheet | 3443 °C | 3074 °C | 2562 °C | 3266 °C | 3464 °C | 3512 °C | 1794 °C | 1529 °C | 3123 °C | 2600 °C | 2868 °C | 1950 °C | 1194 °C | 3395 °C | 2930 °C | 2836 °C |
| Boiling point, cerium foil (Goodfellow) | 3426 °C4 | 3074 °C | 2562 °C | 3266 °C | 3464 °C | 3512 °C | 1794 °C | 1529 °C | 3123 °C | 2600 °C | 2868 °C | 1950 °C | 1194 °C | 3395 °C | 2930 °C | 2836 °C |
| Coefficient of thermal expansion, cerium foil (Goodfellow) | 8 ppm/K7 | 6.7 ppm/K | 9.9 ppm/K | 6.4 ppm/K | 5.1 ppm/K | 4.5 ppm/K | 12.7 ppm/K | 35 ppm/K | 10.3 µm/(m·K) | 11.2 ppm/K | no data | 13.3 ppm/K | 25 ppm/K | 12.5 ppm/K | 11.21 ppm/K | 9.97 ppm/K |
| Tensile strength, cerium foil as rolled (Goodfellow) | 102 MPa10 | no data | no data | 193 MPa | no data | no data | no data | no data | no data | no data | no data | 210 MPa | 68.9 MPa | no data | no data | no data |
| Yield strength, cerium foil as rolled (Goodfellow) | 91 MPa11 | no data | no data | 179 MPa | no data | no data | no data | no data | no data | no data | no data | no data | 65.5 MPa | no data | no data | no data |
Why choose it, and why not
Good for
- UV blocking in cover glass: 1.5% ceria in solar-cell cover glass resisted electron-induced discoloration in the 1973 NASA test.
- Alloys and lighter flints: PubChem says cerium is used in metal alloys and in mischmetal flints for cigarette lighters.
Watch out for
- The metal is a flammable solid, reacts with water and moist air, and burns when finely divided (Ames SDS, CAMEO).
- Property values differ between the Ames SDS and Goodfellow, and the Goodfellow values are for a 90 % purity foil.
- Supply data are for all rare earths together, and China produced 270,000 of 390,000 t in 2025 (USGS).
Cerium metal is a reactive, flammable solid that is handled under argon. Its most useful space-related result is the 1973 NASA test of ceria as a UV-blocking dopant in solar-cell cover glass, which is a laboratory test rather than a flight result. The metal's mechanical values come from one 90 % purity foil, so they should not be used for design without a grade-specific datasheet.
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 | Density, cerium (Ames Laboratory SDS) | Value printed in a safety data sheet for cerium ingot, pieces, rod, foil, sheet and target (Ames Laboratory, 99 to 100 % cerium per section 3) | temperature not statedunit in source 6.77 g/cc (Relative Density, Specific Gravity)form solid, various forms | — |
| 2 | Density, cerium foil (Goodfellow) | Value printed in a supplier product datasheet for a 90 % purity foil | temperature 20 °Cpurity 90 %form foil/sheet, as rolledunit in source 6.75@20°C | The 90 % purity foil and the Ames 99 to 100 % metal differ by 0.02 g/cm3 in density, so both are recorded. |
| 3 | Melting point, cerium foil (Goodfellow) | Value printed in a supplier product datasheet for a 90 % purity foil | purity 90 %form foil/sheet, as rolled | The Ames SDS gives 798 °C for the metal, so the two sources differ by 1 °C. |
| 4 | Boiling point, cerium foil (Goodfellow) | Value printed in a supplier product datasheet for a 90 % purity foil | purity 90 %form foil/sheet, as rolled | The Goodfellow and Ames boiling points differ by 17 °C, which is not reconciled. |
| 5 | Specific heat capacity, cerium foil (Goodfellow) | Value printed in a supplier product datasheet for a 90 % purity foil | temperature 25 °Cpurity 90 %unit in source 205@25°C in J K-1 kg-1 | — |
| 6 | Thermal conductivity, cerium foil (Goodfellow) | Value printed in a supplier product datasheet for a 90 % purity foil | temperature 0 to 100 °Cpurity 90 %unit in source 11.3@0-100°C | — |
| 7 | Coefficient of thermal expansion, cerium foil (Goodfellow) | Value printed in a supplier product datasheet for a 90 % purity foil; 10-6 K-1 is the same unit as ppm/K | temperature 0 to 100 °Cpurity 90 %unit in source 8 x10-6 K-1 at 0-100°C | — |
| 8 | Electrical resistivity, cerium foil (Goodfellow) | Value printed in a supplier product datasheet for a 90 % purity foil; kept in the printed unit | temperature 20 °Cpurity 90 %unit in source 85.4@20°C in µOhmcm | — |
| 9 | Vickers hardness, cerium foil (Goodfellow) | Range printed in a supplier product datasheet for a 90 % purity foil | purity 90 %form foil/sheet, as rolledunit in source 25-30 kgf mm-2 | No canonical name exists for hardness in the property file, so vickers_hardness is a new name and is listed in gaps. The unit is kept as printed. |
| 10 | Tensile strength, cerium foil as rolled (Goodfellow) | Value printed in a supplier product datasheet for a 90 % purity foil; the datasheet does not say whether this is a typical or minimum value | temper as rolledpurity 90 %form foil/sheetunit in source 102 MPa | — |
| 11 | Yield strength, cerium foil as rolled (Goodfellow) | Value printed in a supplier product datasheet for a 90 % purity foil; the datasheet does not say whether this is a typical or minimum value | temper as rolledpurity 90 %form foil/sheetunit in source 91 MPa | — |
Corrosion and compatibility
What happens when it meets other materials and environments.
| Environment | Concern | What happens |
|---|---|---|
| Water and moist air at room temperature | severe | Cerium is readily oxidized by moist air and reacts vigorously with water, liberating flammable hydrogen.1 |
| Strong acids | moderate | Contact with acids may evolve hydrogen gas.2 |
| # | Environment | Details | Test conditions |
|---|---|---|---|
| 1 | Water and moist air at room temperature | CAMEO quotes a datasheet that says the metal is readily oxidized by moist air at room temperature and that it will react vigorously with water or moist air, generating flammable and toxic fumes. The Ames SDS lists water, moisture and air as incompatible and says cerium reacts with water under fire conditions to release hydrogen. PubChem gives H261, in contact with water releases flammable gas, from one notification. | temperature room temperatureatmosphere moist air or waterform metal, not stated |
| 2 | Strong acids | The Ames SDS lists strong acids among incompatible materials and says contact with acids may evolve hydrogen gas. No corrosion rate is printed. | acid strong acids, not namedconcentration not stated |
Risks and side effects
Hazards to people, what happens when a cell overheats, and how the material is handled and stored.
For people
The main hazard is fire and reaction with water, not toxicity. The sources give little toxicology data for the metal.
- The metal
- The Ames SDS classes cerium as a flammable solid, category 1, with signal word Danger and H228. PubChem records H228 in 96.4% of reports, and 11 of 502 reports say the substance does not meet GHS criteria.
- Dust and fumes
- Grinding, melting or welding can produce hazardous dust or fumes, and the SDS gives no exposure limit for cerium.
- Toxicity
- The SDS gives 'No data' for acute toxicity and says the toxicological characteristics are not fully known.
If it fails
The sources give three failure routes: ignition by friction or in fire, hydrogen from water or moist air, and hydrogen from acids.
- Fire
- The metal sparks with friction and burns under fire conditions. CAMEO says finely divided metal is pyrophoric.
- Water and moist air
- Cerium is readily oxidized by moist air and reacts vigorously with water, liberating hydrogen. The ERG guide quoted by CAMEO warns that water on a metal fire generates hydrogen, an extremely dangerous explosion hazard.
- Acids
- Contact with acids may evolve hydrogen gas, according to the Ames SDS.
Handling and storage
- Storage
- Store under argon or mineral oil in tightly closed containers, away from water, moisture, acids and oxidizers.
- Fire
- Use a Class D dry powder agent on fires. Do not use water.
- Spills
- Sweep or scoop spills into a closed container and do not use water for clean-up.
Test details
The original wording and numbers from the sources, for readers who want them.
Failure risks
| Failure | Trigger and consequence |
|---|---|
| Ignition by friction or in firecritical severity | Friction or sparks on the metal, or a fire involving cerium; finely divided metal is more reactiveThe Ames SDS says cerium sparks with friction and will burn under fire conditions. CAMEO, citing Bretherick 1979, says finely divided metal powder is pyrophoric, and says reactivity is enhanced by high physical subdivision such as turnings or gritty powder. |
| Hydrogen release on contact with water or moist aircritical severity | Exposure to water, moisture or moist air, or water used on a metal fireThe Ames SDS says cerium reacts with water under fire conditions and liberates hydrogen gas. CAMEO quotes ERG Guide 170: dousing metallic fires with water will generate hydrogen gas, an extremely dangerous explosion hazard, particularly in confined spaces. |
| Hydrogen evolution with acidsmoderate severity | Contact with strong acidsContact with acids may evolve hydrogen gas (Ames SDS section 10). The SDS does not give a rate. |
Side effects on surrounding parts
| Affects | Effect |
|---|---|
| Workers during machining, melting or welding | Subsequent operations such as grinding, melting or welding may produce potentially hazardous dust or fumes that can be inhaled or contact skin and eyes. The Ames SDS says the product as shipped does not present an inhalation hazard. |
Handling and storage
- Store under argon or mineral oil in tightly closed containers, away from water, moisture, acids and oxidizers, and away from sparks, heat and flame (Ames SDS section 7).
- Handle in an enclosed, controlled process under dry argon, in a humidity-controlled atmosphere, with non-sparking tools (Ames SDS sections 7 and 8).
- Fight fires with a Class D dry powder agent. Do not use water (Ames SDS section 5).
- Sweep or scoop spills into a closed container and do not use water for spill clean-up (Ames SDS section 6).
Supply and geography
How common the raw materials are and where they come from.
Cerium crustal abundance
66.5 ppm of the Earth's crust (USGS PP 1802-A Table A1, citing Jefferson Science Associates 2014)
Rare-earth mine production, 2025 (all rare earths together; cerium is not reported separately)
- Top producers (2025)
- China 69.2%, United States 13.1%, Australia 7.4%, Burma 5.6%
- Critical mineral lists
- US: listed
- Recycling
- USGS: limited quantities of rare earths were recovered from batteries, permanent magnets and fluorescent lamps.
- Substitutes
- USGS: substitutes are available for many applications but generally are less effective.
U.S. imports of rare-earth compounds and metals (all rare earths; 2021 to 2024 combined)
- Top producers (2024)
- China 71%, Malaysia 13%, Japan 5%, Estonia 5%
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.
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spore: profile
id: cerium
spore_version: 0.2
family: rare-earth-metals
name: Cerium
abbreviation: Ce
role: rare-earth metal for alloys and lighter flints; cerium oxide (ceria) used as a glass dopant
category: metals
type: heavy-metals
summary: |
Cerium is the element Ce, a gray metal of the lanthanide series with a density of 6.77 g/cm3 and a melting point of 798 °C (Ames Laboratory SDS). It was first identified in 1803 (Wikipedia). USGS puts its crustal abundance at 66.5 ppm. Cerium is mined as part of the rare-earth group, where China produced 270,000 of 390,000 t in 2025 (USGS). The metal is a flammable solid: it sparks with friction, reacts with water and moist air, and needs a Class D extinguisher. In 1973 NASA Langley showed that cerium oxide (ceria) in solar-cell cover glass resisted radiation-induced discoloration under 1 MeV electrons, a laboratory test and not a flight result.
best_for: Ceria (cerium oxide) as a UV-blocking, radiation-resistant dopant in solar-cell cover glass (NASA 1973 laboratory test)
weakest_at: 'Handling: finely divided metal is pyrophoric, and the metal reacts with water and moist air (Ames SDS, CAMEO)'
identity:
formula: Ce (element, atomic number 58, USGS PP 1802-A periodic table)
cas: 7440-45-1
source: pubchem-ce
where: Compound record, CID 23974, molecular weight 140.116 and CAS 7440-45-1 (REST JSON)
tags:
applications:
- solar-arrays
- structures
stresses:
- total-radiation-dose
properties:
- benchmark: density
label: Density, cerium (Ames Laboratory SDS)
value: 6.77
unit: g/cm3
scope: material
conditions:
temperature: not stated
unit_in_source: 6.77 g/cc (Relative Density, Specific Gravity)
form: solid, various forms
method: Value printed in a safety data sheet for cerium ingot, pieces, rod, foil, sheet and target (Ames Laboratory, 99 to 100 % cerium per section 3)
status: ground
source: ames-ce-sds
where: Section 9, Physical and Chemical Properties, row Relative Density (Specific Gravity)
- benchmark: density
label: Density, cerium foil (Goodfellow)
value: 6.75
unit: g/cm3
scope: material
conditions:
temperature: 20 °C
purity: 90 %
form: foil/sheet, as rolled
unit_in_source: 6.75@20°C
method: Value printed in a supplier product datasheet for a 90 % purity foil
status: ground
note: The 90 % purity foil and the Ames 99 to 100 % metal differ by 0.02 g/cm3 in density, so both are recorded.
source: goodfellow-ce-foil
where: Physical Properties table, row Density (6.75@20°C)
- benchmark: melting_point
label: Melting point, cerium (Ames Laboratory SDS)
value: 798
unit: °C
scope: material
conditions:
unit_in_source: 798 oC
method: Value printed in a safety data sheet
status: ground
source: ames-ce-sds
where: Section 9, Physical and Chemical Properties, row Melting Point
- benchmark: melting_point
label: Melting point, cerium foil (Goodfellow)
value: 799
unit: °C
scope: material
conditions:
purity: 90 %
form: foil/sheet, as rolled
method: Value printed in a supplier product datasheet for a 90 % purity foil
status: ground
note: The Ames SDS gives 798 °C for the metal, so the two sources differ by 1 °C.
source: goodfellow-ce-foil
where: Thermal Properties table, row Melting point (799)
- benchmark: boiling_point
label: Boiling point, cerium (Ames Laboratory SDS)
value: 3443
unit: °C
scope: material
conditions:
pressure: not stated
method: Value printed in a safety data sheet
status: ground
source: ames-ce-sds
where: Section 9, Physical and Chemical Properties, row Boiling Point
- benchmark: boiling_point
label: Boiling point, cerium foil (Goodfellow)
value: 3426
unit: °C
scope: material
conditions:
purity: 90 %
form: foil/sheet, as rolled
method: Value printed in a supplier product datasheet for a 90 % purity foil
status: ground
note: The Goodfellow and Ames boiling points differ by 17 °C, which is not reconciled.
source: goodfellow-ce-foil
where: Physical Properties table, row Boiling point (3426)
- benchmark: specific_heat
label: Specific heat capacity, cerium foil (Goodfellow)
value: 205
unit: J/(kg·K)
scope: material
conditions:
temperature: 25 °C
purity: 90 %
unit_in_source: 205@25°C in J K-1 kg-1
method: Value printed in a supplier product datasheet for a 90 % purity foil
status: ground
source: goodfellow-ce-foil
where: Thermal Properties table, row Specific heat (205@25°C)
- benchmark: thermal_conductivity
label: Thermal conductivity, cerium foil (Goodfellow)
value: 11.3
unit: W/(m·K)
scope: material
conditions:
temperature: 0 to 100 °C
purity: 90 %
unit_in_source: 11.3@0-100°C
method: Value printed in a supplier product datasheet for a 90 % purity foil
status: ground
source: goodfellow-ce-foil
where: Thermal Properties table, row Thermal conductivity (11.3@0-100°C)
- benchmark: cte
label: Coefficient of thermal expansion, cerium foil (Goodfellow)
value: 8
unit: ppm/K
scope: material
conditions:
temperature: 0 to 100 °C
purity: 90 %
unit_in_source: 8 x10-6 K-1 at 0-100°C
method: Value printed in a supplier product datasheet for a 90 % purity foil; 10-6 K-1 is the same unit as ppm/K
status: ground
source: goodfellow-ce-foil
where: Thermal Properties table, row Coefficient of thermal expansion (8@0-100°C)
- benchmark: electrical_resistivity
label: Electrical resistivity, cerium foil (Goodfellow)
value: 85.4
unit: µOhm·cm
scope: material
conditions:
temperature: 20 °C
purity: 90 %
unit_in_source: 85.4@20°C in µOhmcm
method: Value printed in a supplier product datasheet for a 90 % purity foil; kept in the printed unit
status: ground
source: goodfellow-ce-foil
where: Electrical Properties table, row Electrical resistivity (85.4@20°C)
- benchmark: vickers_hardness
label: Vickers hardness, cerium foil (Goodfellow)
value: 25
value_high: 30
bound: range
unit: kgf/mm2
scope: material
conditions:
purity: 90 %
form: foil/sheet, as rolled
unit_in_source: 25-30 kgf mm-2
method: Range printed in a supplier product datasheet for a 90 % purity foil
status: ground
note: No canonical name exists for hardness in the property file, so vickers_hardness is a new name and is listed in gaps. The unit is kept as printed.
source: goodfellow-ce-foil
where: Mechanical Properties table, row Hardness - Vickers (25-30)
- benchmark: ultimate_tensile_strength
label: Tensile strength, cerium foil as rolled (Goodfellow)
value: 102
unit: MPa
scope: material
conditions:
temper: as rolled
purity: 90 %
form: foil/sheet
unit_in_source: 102 MPa
method: Value printed in a supplier product datasheet for a 90 % purity foil; the datasheet does not say whether this is a typical or minimum value
status: ground
source: goodfellow-ce-foil
where: Mechanical Properties table, row Tensile strength (102)
- benchmark: yield_strength
label: Yield strength, cerium foil as rolled (Goodfellow)
value: 91
unit: MPa
scope: material
conditions:
temper: as rolled
purity: 90 %
form: foil/sheet
unit_in_source: 91 MPa
method: Value printed in a supplier product datasheet for a 90 % purity foil; the datasheet does not say whether this is a typical or minimum value
status: ground
source: goodfellow-ce-foil
where: Mechanical Properties table, row Yield strength (91)
corrosion:
- environment: Water and moist air at room temperature
headline: Cerium is readily oxidized by moist air and reacts vigorously with water, liberating flammable hydrogen.
effect: CAMEO quotes a datasheet that says the metal is readily oxidized by moist air at room temperature and that it will react vigorously with water or moist air, generating flammable and toxic fumes. The Ames SDS lists water, moisture and air as incompatible and says cerium reacts with water under fire conditions to release hydrogen. PubChem gives H261, in contact with water releases flammable gas, from one notification.
rating: severe
conditions:
temperature: room temperature
atmosphere: moist air or water
form: metal, not stated
source: cameo-ce
where: Reactivity and hazard text (datasheet quote and ERG Guide 170 entries); Ames SDS section 10
- environment: Strong acids
headline: Contact with acids may evolve hydrogen gas.
effect: The Ames SDS lists strong acids among incompatible materials and says contact with acids may evolve hydrogen gas. No corrosion rate is printed.
rating: moderate
conditions:
acid: strong acids, not named
concentration: not stated
source: ames-ce-sds
where: Section 10, Stability and Reactivity (Incompatible Materials; Possibility of Hazardous Reactions)
risks:
hazards:
- text: 'PubChem aggregates ECHA C&L notifications for 502 company reports: H228 flammable solid (Danger) in 96.4% of reports; H302 and H312 at 100% (Warning); H261 and H370 from single notifications with no percentage printed; 11 of 502 reports (2.2%) say the substance does not meet GHS criteria.'
ghs:
- H228
- H261
- H302
- H312
- H370
source: pubchem-ce
where: GHS Classification, aggregated ECHA C&L summary and notification list
- text: 'Ames Laboratory SDS for cerium ingot, pieces, rod, foil, sheet and target: GHS flammable solid, category 1, signal word Danger, H228. Handle under inert gas, protect from moisture, and use a Class D extinguisher.'
ghs:
- H228
source: ames-ce-sds
where: Sections 2 and 5
- text: No OSHA or ACGIH exposure limit is established for cerium (Ames SDS). The SDS gives 'No data' for acute toxicity and says the toxicological characteristics are not fully known.
ghs: []
source: ames-ce-sds
where: Section 8, Exposure Limits; Section 11, Toxicological Information
failure_risks:
- mode: Ignition by friction or in fire
trigger: Friction or sparks on the metal, or a fire involving cerium; finely divided metal is more reactive
consequence: The Ames SDS says cerium sparks with friction and will burn under fire conditions. CAMEO, citing Bretherick 1979, says finely divided metal powder is pyrophoric, and says reactivity is enhanced by high physical subdivision such as turnings or gritty powder.
severity: critical
source: ames-ce-sds
where: Sections 2, 5 and 10; CAMEO reactivity text
- mode: Hydrogen release on contact with water or moist air
trigger: Exposure to water, moisture or moist air, or water used on a metal fire
consequence: 'The Ames SDS says cerium reacts with water under fire conditions and liberates hydrogen gas. CAMEO quotes ERG Guide 170: dousing metallic fires with water will generate hydrogen gas, an extremely dangerous explosion hazard, particularly in confined spaces.'
severity: critical
source: cameo-ce
where: Reactivity and hazard text; ERG Guide 170 entries
- mode: Hydrogen evolution with acids
trigger: Contact with strong acids
consequence: Contact with acids may evolve hydrogen gas (Ames SDS section 10). The SDS does not give a rate.
severity: moderate
source: ames-ce-sds
where: Section 10, Possibility of Hazardous Reactions
side_effects:
- text: Subsequent operations such as grinding, melting or welding may produce potentially hazardous dust or fumes that can be inhaled or contact skin and eyes. The Ames SDS says the product as shipped does not present an inhalation hazard.
affects: Workers during machining, melting or welding
source: ames-ce-sds
where: Section 4, General Measures; Section 11, Likely Routes of Exposure
handling:
- text: Store under argon or mineral oil in tightly closed containers, away from water, moisture, acids and oxidizers, and away from sparks, heat and flame (Ames SDS section 7).
source: ames-ce-sds
where: Section 7, Conditions for Safe Storage
- text: Handle in an enclosed, controlled process under dry argon, in a humidity-controlled atmosphere, with non-sparking tools (Ames SDS sections 7 and 8).
source: ames-ce-sds
where: Section 7, Precautions for Safe Handling; Section 8, Engineering Controls
- text: Fight fires with a Class D dry powder agent. Do not use water (Ames SDS section 5).
source: ames-ce-sds
where: Section 5, Firefighting Measures
- text: Sweep or scoop spills into a closed container and do not use water for spill clean-up (Ames SDS section 6).
source: ames-ce-sds
where: Section 6, Accidental Release Measures
mitigations: []
uses:
- application: solar-arrays
device: Solar-cell cover glass made from 1.5% ceria-doped Micro-Sheet (cerium oxide dopant)
example: NASA Langley irradiated 1.5% ceria-doped cover glass with 1 MeV electrons. The doped glass was much less sensitive to radiation-induced discoloration than undoped cover glass, and the report calls it comparable to synthetic fused silica for this application. This was a laboratory irradiation test, not a flight result.
source: nasa-tn-d7245
where: Abstract and Concluding Remarks (NASA TN D-7245, May 1973)
- application: structures
device: Metal alloys containing cerium, including mischmetal
example: PubChem, citing Ullmann, says cerium is used in metal alloys, in polishing agents and in glass, and that mischmetal is used to make flints for cigarette lighters. The source does not name an aerospace alloy.
source: pubchem-ce
where: Use and Manufacturing, Sources/Uses (Ullmann, cited)
supply:
- subject: Cerium crustal abundance
abundance: 66.5 ppm of the Earth's crust (USGS PP 1802-A Table A1, citing Jefferson Science Associates 2014)
producers: []
critical_lists: []
source: usgs-pp1802a
where: Table A1, Crustal abundances of mineral commodities, row Cerium (Ce)
- subject: Rare-earth mine production, 2025 (all rare earths together; cerium is not reported separately)
producers:
- country: China
share_percent: 69.2
year: 2025
- country: United States
share_percent: 13.1
year: 2025
- country: Australia
share_percent: 7.4
year: 2025
- country: Burma
share_percent: 5.6
year: 2025
critical_lists:
- list: USGS 2025 List of Critical Minerals (cerium named individually)
listed: true
recycling: 'USGS: limited quantities of rare earths were recovered from batteries, permanent magnets and fluorescent lamps.'
substitutes:
- 'USGS: substitutes are available for many applications but generally are less effective.'
source: usgs-mcs2026-rare-earths
where: 'World Mine Production table, 2025 (China 270,000 t, United States 51,000 t, Australia 29,000 t, Burma 22,000 t, world total 390,000 t rounded). Shares are calculated by Space Mushroom from the printed values and are rare-earth oxide equivalent. Recycling; Substitutes. Critical list: usgs-crit2025.'
- subject: U.S. imports of rare-earth compounds and metals (all rare earths; 2021 to 2024 combined)
producers:
- country: China
share_percent: 71
year: 2024
- country: Malaysia
share_percent: 13
year: 2024
- country: Japan
share_percent: 5
year: 2024
- country: Estonia
share_percent: 5
year: 2024
critical_lists: []
source: usgs-mcs2026-rare-earths
where: Import Sources (2021 to 2024) paragraph. The year field is the last year of the range. These are import shares, not production shares.
documents:
- title: 'Safety Data Sheet: Cerium, ingot, pieces, rod, foil, sheet and target (Ames Laboratory, US DOE, Materials Preparation Center)'
type: sds
url: https://www.ameslab.gov/sites/default/files/inline-files/58_Cerium_SDS.pdf
year: 2024
- title: Goodfellow cerium foil/sheet, 50 x 50 mm, 0.25 mm (SKU 1000225237), product datasheet
type: datasheet
url: https://www.goodfellow.com/usa/cerium-foil-1000225237
- title: 'PubChem compound record: Cerium (CID 23974), GHS classification and use summary'
type: database
url: https://pubchem.ncbi.nlm.nih.gov/compound/23974
year: 2026
- title: 'Mineral Commodity Summaries 2026: Rare Earths (USGS)'
type: report
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf
year: 2026
- title: 'Critical Mineral Resources of the United States: An Introduction (USGS Professional Paper 1802-A), Table A1'
type: report
url: https://pubs.usgs.gov/pp/1802/a/pp1802a.pdf
year: 2017
- title: 'NASA Technical Note D-7245: Effect of 1 MeV Electrons on Ceria-Doped Solar Cell Cover Glass (Haynes, Langley Research Center)'
type: report
url: https://ntrs.nasa.gov/citations/19730015355
year: 1973
- title: 'CAMEO Chemicals: Cerium, slabs, ingots or rods (NOAA)'
type: database
url: https://cameochemicals.noaa.gov/chemical/2844
- title: 'Wikipedia: Cerium (history and mineral sources only)'
type: database
url: https://en.wikipedia.org/wiki/Cerium
year: 2026
gaps:
- 'Elastic constants: no Young''s modulus, shear modulus or Poisson''s ratio for cerium was read in a fetched source. Wikipedia prints a Young''s modulus, but the brief limits Wikipedia to composition and history, so it was not used.'
- 'Purity: the Goodfellow properties are for a 90 % purity foil, and the Ames SDS covers the 99 to 100 % metal. The two sets are recorded separately and not reconciled. Goodfellow''s rod datasheet was not found.'
- 'Hardness: Vickers hardness is printed in kgf/mm2 for the 90 % foil. The property file has no canonical name for hardness, so vickers_hardness is a new name.'
- 'Strength: the tensile and yield values are for as-rolled 90 % foil. No grade, temper or minimum-value table for pure cerium was found, and Goodfellow does not say whether the values are typical or minimum.'
- 'Corrosion rate: no quantitative oxidation or corrosion rate for cerium metal in air or humidity was read. A Corrosion Science paper on cerium oxidation in water vapour was seen only in search results and not opened.'
- 'EU critical raw materials list: the European Commission page read here does not name cerium or the light rare earths, so no EU listing is recorded for cerium.'
- 'Production route: no source read gives the reduction or metal-making process for cerium. The recipe names only the ore minerals (bastnaesite and monazite) from USGS and Wikipedia.'
- Supply shares are for all rare earths together (USGS does not report cerium separately). They are rare-earth oxide equivalent and are not a cerium-only share.
- 'Pyrophoric statement: the pyrophoric wording for finely divided metal comes from CAMEO, which cites Bretherick 1979. The Bretherick text was not opened and no measured ignition temperature was found.'
- 'Hazard classification: PubChem gives H261 and H370 from single notifications and H228 in 96.4% of reports, while the Ames SDS gives only H228. The percentages for H261 and H370 are not printed.'
- 'Space use: the only space-related source is a 1973 laboratory irradiation of ceria-doped cover glass (NASA TN D-7245). No flight result and no cerium metal space use was found. No environment tags are set because no source ties cerium to a specific environment.'
- 'Mitigations: no source read gives a mitigation for the water, air or fire hazards beyond the handling steps above.'
- 'Designations: no alloy or grade designation for cerium metal was found in a fetched source. UN 1333 is a transport number, not a designation in the list used for this profile.'
sources:
ames-ce-sds:
title: 'Safety Data Sheet: Cerium (Ames Laboratory, US DOE, Materials Preparation Center)'
id: CAS 7440-45-1, UN 1333
url: https://www.ameslab.gov/sites/default/files/inline-files/58_Cerium_SDS.pdf
year: 2024
kind: datasheet
license: supplier safety data sheet, cited not reproduced
goodfellow-ce-foil:
title: Cerium foil/sheet, 50 x 50 mm, 0.25 mm, as rolled, 90 % purity (Goodfellow product datasheet)
id: SKU 1000225237
url: https://www.goodfellow.com/usa/cerium-foil-1000225237
kind: datasheet
license: supplier web page, cited not reproduced
pubchem-ce:
title: 'PubChem compound record: Cerium (CID 23974), GHS classification and use summary'
id: CID 23974; CAS 7440-45-1
url: https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/23974/JSON
year: 2026
kind: database
license: public domain (NCBI); sections attributed to ECHA, Ullmann and others
usgs-mcs2026-rare-earths:
title: 'Mineral Commodity Summaries 2026: Rare Earths (USGS)'
id: USGS MCS 2026, February 2026
url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-rare-earths.pdf
year: 2026
kind: report
license: public domain (USGS)
usgs-pp1802a:
title: 'Critical Mineral Resources of the United States: An Introduction (Professional Paper 1802-A), Table A1, crustal abundances'
id: USGS PP 1802-A
url: https://pubs.usgs.gov/pp/1802/a/pp1802a.pdf
year: 2017
kind: report
license: public domain (USGS)
usgs-crit2025:
title: About the 2025 List of Critical Minerals (USGS, final list of 60 minerals)
id: Final 2025 List of Critical Minerals, November 2025
url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
year: 2025
kind: web
license: public domain (USGS)
nasa-tn-d7245:
title: Effect of 1 MeV Electrons on Ceria-Doped Solar Cell Cover Glass (NASA Technical Note D-7245, Langley Research Center, Haynes)
id: NASA TN D-7245; L-8785
url: https://ntrs.nasa.gov/citations/19730015355
year: 1973
kind: report
license: public domain (NASA)
cameo-ce:
title: 'CAMEO Chemicals: Cerium, slabs, ingots or rods (NOAA)'
id: CAMEO chemical 2844; UN/NA 1333
url: https://cameochemicals.noaa.gov/chemical/2844
kind: database
license: public domain (NOAA)
wikipedia-ce:
title: Cerium (Wikipedia)
url: https://en.wikipedia.org/wiki/Cerium
year: 2026
kind: web
license: CC BY-SA 4.0 (cited, not reproduced)
license: CC-BY-4.0
updated: '2026-10-26'
review:
status: draft
method: assistant
checked_values: 13
unreachable: 1
caveats: 5
note: 'Read by an AI assistant on 2026-10-26 from the pages and PDFs named in each entry. Unreachable: American Elements cerium page (HTTP 403). Caveats: the Goodfellow values are for a 90 % purity foil, not the 99 to 100 % metal in the Ames SDS; the supply shares are for all rare earths together; the strength values are as-rolled foil with no minimum stated; the boiling point and melting point differ between the Ames SDS and Goodfellow; no corrosion rate for cerium metal was found.'
story:
recipe:
line: Cerium is a single-element metal (Ce). It is not alloyed in the profile. Its ores are the minerals of the bastnaesite and monazite groups (Wikipedia); USGS reports bastnaesite mined at Mountain Pass, California, and monazite produced from heavy-mineral-sand concentrates in the southeastern United States. No source read gives the reduction process.
parts:
- name: Cerium
symbol: Ce
atoms: 1
atomic_weight: 140.116
role: The whole material. The Ames SDS lists cerium at 100 % in section 3 (ingot, pieces, rod, foil, sheet and target), and the Goodfellow foil is 90 % purity.
risk_groups:
- title: For people
level: 1
verdict: Flammable solid, category 1
lead: The main hazard is fire and reaction with water, not toxicity. The sources give little toxicology data for the metal.
points:
- label: The metal
line: The Ames SDS classes cerium as a flammable solid, category 1, with signal word Danger and H228. PubChem records H228 in 96.4% of reports, and 11 of 502 reports say the substance does not meet GHS criteria.
- label: Dust and fumes
line: Grinding, melting or welding can produce hazardous dust or fumes, and the SDS gives no exposure limit for cerium.
- label: Toxicity
line: The SDS gives 'No data' for acute toxicity and says the toxicological characteristics are not fully known.
- title: If it fails
lead: 'The sources give three failure routes: ignition by friction or in fire, hydrogen from water or moist air, and hydrogen from acids.'
points:
- label: Fire
line: The metal sparks with friction and burns under fire conditions. CAMEO says finely divided metal is pyrophoric.
- label: Water and moist air
line: Cerium is readily oxidized by moist air and reacts vigorously with water, liberating hydrogen. The ERG guide quoted by CAMEO warns that water on a metal fire generates hydrogen, an extremely dangerous explosion hazard.
- label: Acids
line: Contact with acids may evolve hydrogen gas, according to the Ames SDS.
- title: Handling and storage
points:
- label: Storage
line: Store under argon or mineral oil in tightly closed containers, away from water, moisture, acids and oxidizers.
- label: Fire
line: Use a Class D dry powder agent on fires. Do not use water.
- label: Spills
line: Sweep or scoop spills into a closed container and do not use water for clean-up.
why: 'Cerium is a reactive rare-earth metal. The SDS treats it as a flammable solid, so the metal is handled under argon and kept away from water. Its main uses in this profile are not as the metal: NASA tested cerium oxide (ceria) as a dopant in solar-cell cover glass in 1973, and it resisted radiation-induced discoloration. PubChem says the metal goes into alloys, polishing agents and glass, and into mischmetal flints for cigarette lighters. Cerium was first identified in 1803.'
uses:
- where: Solar-cell cover glass
line: In the 1973 NASA Langley test, 1.5% ceria-doped cover glass was much less sensitive to electron-induced discoloration than undoped glass, and the report calls it comparable to synthetic fused silica. It was a laboratory test, not a flight result.
- where: Alloys and lighter flints
line: PubChem, citing Ullmann, says cerium is used in metal alloys, polishing agents and glass, and that mischmetal makes flints for cigarette lighters. The source names no aerospace alloy.
can_do:
- label: Density
value: 6.77 g/cm3
benchmark: density
line: The Ames Laboratory SDS gives a relative density of 6.77 g/cc. Goodfellow's 90 % foil gives 6.75 g/cm3 at 20 °C.
- label: Melting
value: 798 °C
benchmark: melting_point
line: The Ames SDS gives a melting point of 798 °C, and Goodfellow's foil gives 799 °C.
- label: Strength as rolled
value: 102 MPa
line: Goodfellow's 90 % purity foil, as rolled, gives 102 MPa tensile and 91 MPa yield. The datasheet does not say whether these are minimum values.
- label: Abundance
value: 66.5 ppm
line: USGS PP 1802-A gives cerium a crustal abundance of 66.5 ppm.
compare: Cerium is a reactive metal rather than a structural one. Its SDS treats it as a flammable solid, and it reacts with water and moist air, which sets it apart from the other metals in this collection. Its space record is as an oxide, ceria, in glass rather than as the metal. This profile has no other metal read in the same run, so the compare rows below give cerium's own values only.
compare_rows:
- label: Density
benchmark: density
- label: Melting point
benchmark: melting_point
- label: Thermal conductivity
benchmark: thermal_conductivity
handling:
- Store under argon or mineral oil in tightly closed containers, away from water, moisture and acids (Ames SDS).
- Handle under dry argon in a controlled process, with non-sparking tools (Ames SDS).
- Use a Class D dry powder agent on a fire. Never use water (Ames SDS).
good_for:
- 'UV blocking in cover glass: 1.5% ceria in solar-cell cover glass resisted electron-induced discoloration in the 1973 NASA test.'
- 'Alloys and lighter flints: PubChem says cerium is used in metal alloys and in mischmetal flints for cigarette lighters.'
watch_out:
- The metal is a flammable solid, reacts with water and moist air, and burns when finely divided (Ames SDS, CAMEO).
- Property values differ between the Ames SDS and Goodfellow, and the Goodfellow values are for a 90 % purity foil.
- Supply data are for all rare earths together, and China produced 270,000 of 390,000 t in 2025 (USGS).
verdict: Cerium metal is a reactive, flammable solid that is handled under argon. Its most useful space-related result is the 1973 NASA test of ceria as a UV-blocking dopant in solar-cell cover glass, which is a laboratory test rather than a flight result. The metal's mechanical values come from one 90 % purity foil, so they should not be used for design without a grade-specific datasheet.
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 |
|---|---|---|---|---|
| Safety Data Sheet: Cerium (Ames Laboratory, US DOE, Materials Preparation Center) | datasheet | 2024 | 13 values | |
| Cerium foil/sheet, 50 x 50 mm, 0.25 mm, as rolled, 90 % purity (Goodfellow product datasheet) | datasheet | 10 values | ||
| PubChem compound record: Cerium (CID 23974), GHS classification and use summary | database | 2026 | 3 values | |
| Mineral Commodity Summaries 2026: Rare Earths (USGS) | report | 2026 | 2 values | |
| Critical Mineral Resources of the United States: An Introduction (Professional Paper 1802-A), Table A1, crustal abundances | report | 2017 | 1 value | |
| About the 2025 List of Critical Minerals (USGS, final list of 60 minerals) | web | 2025 | 0 values | |
| Effect of 1 MeV Electrons on Ceria-Doped Solar Cell Cover Glass (NASA Technical Note D-7245, Langley Research Center, Haynes) | report | 1973 | 1 value | |
| CAMEO Chemicals: Cerium, slabs, ingots or rods (NOAA) | database | 2 values | ||
| Cerium (Wikipedia) | web | 2026 | 0 values |