NAMES
Ceria, ceric oxide, cerium dioxide
All are common names for CeO₂. “Ceria” is especially common in materials science, catalysis and polishing literature.[1]
ELEMENT 58 → OXIDE PLATFORM
CeO₂Cerium oxide / ceria — one formula, many surface chemistries.
CeO₂ is more than a rare-earth oxide. Its cubic fluorite lattice tolerates oxygen loss, its surface can cycle between Ce⁴⁺ and Ce³⁺, and that defect chemistry connects seemingly different technologies: glass polishing, semiconductor CMP, automotive catalysts, solid-oxide electrochemistry, UV-protective coatings and more.[4]
01 / IDENTITY
Start with the facts.
CeO₂ is cerium(IV) oxide, commonly called ceria. PubChem lists CAS 1306-38-3 and a molecular weight of 172.115 g/mol, and notes uses including glass polishing, infrared-filter coatings and catalysis.[1]
CeO₂MOLECULAR FORMULA
172.115g/mol · MOLECULAR WEIGHT
1306-38-3CAS REGISTRY NUMBER
Fm-3mCUBIC FLUORITE SPACE GROUP
≈5.411 ÅEXPERIMENTAL LATTICE CONSTANT
APPEARANCE
Pure ceria is pale yellow
The color is associated with charge transfer; stronger reduction and greater oxygen-vacancy density can shift reduced ceria toward blue or black without requiring a change of the fluorite phase.[6]
WHY IT MATTERS
A defect-tolerant oxide
The fluorite lattice can accommodate oxygen vacancies and associated Ce³⁺ centers, enabling oxygen exchange, redox chemistry and reactivity that can be engineered through composition, morphology and processing.[4]
02 / CRYSTAL
INTERACTIVE-STYLE CSS MODEL
Ce siteO site
STRUCTURE → PROPERTY
Why a crystal structure can determine a market.
A stable fluorite framework can tolerate deviations from perfect CeO₂ stoichiometry. Removing oxygen leaves electrons that can localize on cerium, generating Ce³⁺ sites and oxygen vacancies. These defects are not merely imperfections: they help govern oxygen mobility, adsorption, catalytic barriers, ion conduction and surface reaction chemistry.[4]
Surface planesDifferent facets have different vacancy formation energies and adsorption behavior.
Particle sizeChanges surface-to-volume ratio and the population of surface sites.
DopingCan change vacancy concentration, ionic conductivity and thermal/redox behavior.
Atmosphere / TReactive gases and temperature can rearrange vacancies and polarons dynamically.
03 / VACANCIES
VACANCY EXPLORER
CeO2.00
Move the slider to visualize an ideal charge-balance concept: removing one O²⁻ leaves two electrons, which can convert two Ce⁴⁺ to Ce³⁺. Real CeO₂−x surfaces are more complex; defect clustering, polarons, facets, temperature and atmosphere matter.[4]
x = 0.00IDEAL OXYGEN DEFICIENCY
0%IDEALIZED Ce³⁺ FRACTION ≈ 2x
OxidizedCONCEPTUAL REDOX STATE
Illustrative stoichiometric model only — not an equilibrium calculation, not a specification for commercial ceria.
OXYGEN STORAGE
Store / release oxygen
CeO₂-based materials can reversibly accommodate oxygen deficiency, which is central to oxygen storage capacity (OSC) in automotive emission-control catalysts.[8]
POLARONS
Electrons localize as Ce³⁺
Vacancy formation is tightly coupled to localized electronic states (polarons), influencing transport, adsorption sites and reaction barriers.[4]
DOPING
Defect engineering
Gd, Sm and other dopants are used to increase oxygen-vacancy populations and tune oxide-ion conduction, especially for intermediate-temperature SOFC electrolytes.[14]
04 / POLISHING
Why CeO₂ polishes glass so well.
Ceria is not simply a hard grain scratching a softer surface. Classic and modern CMP literature points to coupled chemical and mechanical removal. CeO₂ can form interfacial Ce–O–Si bonds with silica-containing surfaces, then mechanical action helps break the network and remove material.[9][10]
01 / CONTACTCeria meets hydrated silica
The slurry brings CeO₂ abrasive surfaces into repeated contact with SiO₂-rich glass or dielectric surfaces.
Si–O–Si + HO–surface
→
02 / CHEMICAL COUPLINGCe–O–Si bonds form
Interfacial reaction strains the silica network. Recent reviews describe the classic “chemical tooth” picture and the importance of Ce³⁺-related surface chemistry.
surface–Ce–O–Si–surface
→
03 / REMOVALMechanical tearing releases material
Shear and pressure assist bond rupture and removal of silica-containing fragments, producing chemical–mechanical rather than purely abrasive action.
reaction + shear → removal
1803
Cerium was discovered in oxide form; the name “ceria” traces to Ceres.[18]
1930s
Cerium compounds began to be used as glass polishes; rare-earth polishing expanded industrially thereafter.[11]
2001
A widely cited SiO₂ CMP study found evidence for surface reaction and multiple Si–O–Ce bonds before mechanical removal.[9]
05 / ENGINEERING
“CeO₂ purity” is not enough to predict polishing.
Performance emerges from a system: phase/crystallinity, surface valence, particle-size distribution, morphology, aggregation, slurry chemistry, pad, pressure, speed and the material being polished. A 2016 study found calcination temperature strongly affected crystallinity, Ce³⁺ content and polishing efficiency in its tested powders.[13]
01 · CalcinationControls phase development, crystallinity, crystallite growth, surface area and often surface chemistry.
02 · PSD / D50 / tailD50 alone does not describe oversize tails. Large particles or agglomerates can dominate scratch risk.
03 · Ce³⁺ / vacanciesSurface valence state can influence chemical interaction with silica and polishing behavior.
04 · MorphologySpheres, cubes, rods, porous and core-shell designs change contact geometry and surface exposure.
05 · DispersionAgglomeration, zeta potential, additives and ionic environment determine whether “nano” particles behave nano-scale in slurry.
06 · Slurry chemistrypH, complexants, oxidizers, surfactants and solids loading can shift reaction and transport behavior.
07 · Pad / pressureContact mechanics and hydrodynamics control real contact area, transport and removal rate.
08 · Post-cleanCeria residue can be difficult to remove in advanced CMP, so cleaning chemistry is part of process design.
PROCESS NOTE
Calcination is not a universal “higher is better” variable.
In one controlled glass-polishing study, ceria calcined at 700 °C and above showed good polishing efficiency and the tested 1050 °C sample reached the highest efficiency; the authors linked results to crystallinity and Ce³⁺ content. That should be treated as a study-specific result, not a universal recipe for every precursor, glass, slurry or polishing platform.[13]
06 / APPLICATIONS
One oxide, multiple industries.
Use the tabs to see how the same CeO₂ defect chemistry is exploited differently.
SiO₂ loves ceria chemistry.
CeO₂ is widely used for glass polishing and is a key abrasive for silica dielectric CMP, where its chemical activity and selectivity are useful in processes such as shallow trench isolation (STI).[17]
Optical glass — lenses, prisms and precision glass finishing.
Displays / photomasks — high-flatness glass surfaces.
Semiconductor CMP — silica/dielectric planarization and STI selectivity.
SiC research — CeO₂ composite particles are actively studied to improve chemically assisted removal of very hard SiC wafers.[16]
An oxygen buffer with a reactive surface.
The Ce⁴⁺/Ce³⁺ redox couple and oxygen vacancies allow ceria to take up and release oxygen. This is central to three-way automotive catalysts and also relevant to CO oxidation, water–gas shift, soot/VOC oxidation and other heterogeneous catalytic systems.[7][8]
Oxygen storage capacity (OSC)
Support for precious and transition metals
Dynamic metal–ceria interfaces
Vacancy-driven adsorption and redox pathways
Vacancies become ion highways.
Doping ceria with trivalent or divalent cations creates oxygen vacancies that can strongly increase oxide-ion conductivity. Gd-doped ceria (GDC) and Sm-doped ceria (SDC) are prominent intermediate-temperature SOFC electrolyte materials, though ceria can develop mixed ionic/electronic conduction in reducing atmospheres.[14][15]
GDC — gadolinium-doped ceria
SDC — samarium-doped ceria
Intermediate-temperature SOFCs
Mixed-conduction limitation under reducing conditions
Ceria can manage light as well as surfaces.
CeO₂ absorbs UV and has a relatively high refractive index, motivating research and use in UV-protective and anti-reflective coatings. Surface treatment or doping may be used to manage dispersion and unwanted photocatalytic behavior depending on the formulation.[19][20]
UV-absorbing transparent coatings
High-index thin-film concepts
Infrared-filter / optical coating uses noted by PubChem
Dispersion and surface-functionalization are critical for transparent formulations
Nanoceria is chemically interesting — and risk-sensitive.
Nanoceria is widely researched for redox-active biological and environmental applications, but published toxicology findings vary and depend strongly on particle size, morphology, aggregation, surface charge, coating and valence state. Research interest should not be confused with established medical use.[21]
Gas sensors and redox sensing
Electrocatalysis and oxygen reduction research
Antioxidant / biomedical research
Environmental fate and nano-specific exposure assessment
07 / MANUFACTURING
From rare-earth mineral to controlled abrasive.
Commercial ceria starts with rare-earth feedstocks such as bastnäsite and monazite, followed by separation chemistry and conversion to cerium-rich precursors. For polishing grades, calcination, milling and particle classification are decisive manufacturing steps.[2][11]
01 · ORE / CONCENTRATE
Bastnäsite, monazite and other rare-earth sources.
02 · SEPARATION
Leaching / separation isolates a cerium-rich chemical stream.
03 · PRECURSOR
Carbonate, oxalate, hydroxide or related cerium precursor.
04 · CALCINATION
Thermal conversion develops CeO₂ phase, crystallinity and surface properties.
05 · MILL / CLASSIFY
Particle-size distribution and oversize control are engineered.
06 · POWDER / SLURRY
Dry grade or dispersed formulation for a target application.
RARE-EARTH CONTEXT
Cerium is unusually abundant for a “rare earth.”
USGS lists cerium as the most abundant rare-earth element in Earth’s crust at about 60 ppm and identifies bastnäsite, monazite, loparite and lateritic ion-adsorption clays among principal economic rare-earth sources.[2]
2026 SUPPLY CONTEXT
Rare-earth supply is strategic, but CeO₂ is not the same market as magnet REEs.
USGS 2026 treats rare earths as a group and reports current production, trade and policy conditions. When assessing CeO₂ supply, distinguish high-volume cerium compounds and polishing grades from high-value magnet materials such as Nd-Pr-Dy-Tb.[22]
08 / SAFETY
Bulk chemical identity and nano-risk are not the same question.
PubChem currently shows ceria’s primary hazards as “Not Classified” on its summary page, but that should not replace a supplier SDS, workplace exposure controls or nano-specific assessment for fine powders.[1]
DUST
Control airborne powder
Use the current SDS, appropriate ventilation and dust-control practices. Fine and ultrafine powders warrant stronger attention to inhalation exposure than bulk solid pieces.
NANOCERIA
Physicochemical form matters
Size, morphology, agglomeration, surface charge, coating and surface valence can influence environmental behavior and toxicity; literature remains condition-dependent and sometimes contradictory.[21]
PROCUREMENT
Ask for grade-specific documents
For industrial buying, request the current TDS, COA and SDS for the actual grade. “CeO₂” alone does not define PSD, purity, TREO, surface area, morphology or slurry additives.
09 / FAQ
CeO₂ questions people actually search.
What is CeO₂?
CeO₂ is cerium(IV) oxide, commonly called ceria, ceric oxide or cerium dioxide. PubChem lists formula CeO₂, CAS 1306-38-3 and molecular weight 172.115 g/mol.[1]
Why is cerium oxide used for glass polishing?
Because polishing is chemical–mechanical: ceria can chemically interact with silica-containing surfaces and form Ce–O–Si interfacial bonds, while pressure and shear help remove the reacted surface. Its combination of reactivity and moderate mechanical action can produce high removal rates with controlled surface damage.[9][10]
What is the difference between CeO₂ and CeO₂−x?
CeO₂ describes the ideal stoichiometric oxide. CeO₂−x describes oxygen-deficient ceria. Oxygen removal produces vacancies and is coupled to reduction of some Ce⁴⁺ toward Ce³⁺, changing surface and transport properties.[4]
Does higher CeO₂ purity always mean better polishing?
No. Purity is only one variable. Particle-size distribution, oversize/agglomerates, crystallinity, surface Ce³⁺, morphology, dispersion, slurry chemistry, pad and process conditions all affect performance. A grade must be matched to the substrate and process.
Is CeO₂ used in semiconductor CMP?
Yes. Ceria is a key abrasive for SiO₂ dielectric CMP and is particularly valued for chemical activity and selectivity in applications such as STI. Current research also targets composite particles, surface modification, dispersion stability and post-CMP cleaning.[12][17]
What are oxygen vacancies in ceria?
They are missing oxygen atoms in the lattice. The electrons associated with oxygen removal can localize on Ce ions, generating Ce³⁺ sites. Vacancies and polarons influence oxygen exchange, adsorption, catalysis and ion transport.[4]
What is doped ceria?
Doped ceria replaces a fraction of Ce with other cations. Trivalent dopants such as Gd or Sm create oxygen vacancies for charge compensation and can strongly raise oxide-ion conductivity, which is useful for intermediate-temperature SOFC electrolytes.[14]
Where does cerium come from?
USGS identifies bastnäsite, monazite, loparite and lateritic ion-adsorption clays as principal economic rare-earth sources and notes that cerium is the most abundant rare-earth element in Earth’s crust at about 60 ppm.[2]
10 / SOURCES
Source-led, not keyword-stuffed.
This page synthesizes government data, PubChem and peer-reviewed literature. Claims are paraphrased; links below lead to the underlying sources.
[1] PubChem — Ceria (CID 73963).
pubchem.ncbi.nlm.nih.gov/compound/Ceria
pubchem.ncbi.nlm.nih.gov/compound/Ceria
[2] U.S. Geological Survey — Rare Earths Statistics and Information.
USGS rare-earth statistics
USGS rare-earth statistics
[3] IUCr — CeO₂ fluorite lattice, experimental a = 5.411 Å.
journals.iucr.org
journals.iucr.org
[4] ACS / PMC (2025) — Oxygen vacancies in ceria: formation, behavior and catalytic roles.
PMC12041958
PMC12041958
[5] IUCr (1999) — EXAFS structure of CeO₂.
CeO₂ coordination / Fm-3m
CeO₂ coordination / Fm-3m
[6] PMC (2023) — Doped ceria: preparation, properties and uses.
PMC10468777
PMC10468777
[7] PMC (2022) — CeO₂ catalysts: electronic properties and energy applications.
PMC9772620
PMC9772620
[8] Catalysis Today (2019) — Review of oxygen storage capacity of CeO₂-based materials.
ScienceDirect
ScienceDirect
[9] J. Non-Crystalline Solids (2001) — Mechanism of polishing SiO₂ films by CeO₂.
ScienceDirect
ScienceDirect
[10] Powder Technology (2024) — Review on development of ceria for CMP.
ScienceDirect
ScienceDirect
[11] Journal of Alloys and Compounds (1994) — Cerium-based polishing compounds: discovery to manufacture.
ScienceDirect
ScienceDirect
[12] Journal of Rare Earths (2026) — Ceria nanoparticle synthesis and CMP advances.
ScienceDirect
ScienceDirect
[13] Wear (2016) — Physicochemical characteristics vs glass-polishing efficiency.
ScienceDirect
ScienceDirect
[14] PMC — Rare-earth-doped ceria: structure and defect chemistry.
PMC6220118
PMC6220118
[15] PMC — Tutorial review on SOFC materials and doped ceria electrolytes.
SOFC tutorial review
SOFC tutorial review
[16] ACS Applied Materials & Interfaces (2026) — CeO₂ composite particles for SiC CMP.
ACS AMI
ACS AMI
[17] ACS Applied Materials & Interfaces (2026) — Abrasives for semiconductor CMP.
ACS AMI
ACS AMI
[18] PMC — Environmental geochemistry of cerium.
PMC4344665
PMC4344665
[19] PMC — Oxide nanoparticles for UV-protective coatings.
PMC5074370
PMC5074370
[20] Applied Sciences (2019) — Cerium oxide thin coatings with anti-reflective properties.
MDPI Applied Sciences
MDPI Applied Sciences
[21] PubMed (2020) — Surface properties, environmental transformation and toxicity of nanoceria.
PubMed 32462332
PubMed 32462332
[22] USGS Mineral Commodity Summaries 2026 — Rare Earths.
USGS 2026 PDF
USGS 2026 PDF
EXPOLISH
Commercial CeO₂ questions need grade-level answers.
For product selection, specify the substrate, polishing stage, desired removal rate / finish, equipment, slurry system and target particle-size range. The chemistry is CeO₂; the engineering is the grade.
COMPANY
Hangzhou Explore Polishing Technology Co., Ltd.
BrandEXPOLISH
Chinese Legal Name杭州探索抛光技术有限公司
Unified Social Credit Code91330114MAKJMCT16A
Registration No.330114000734317
EstablishedAugust 7, 2026
CONTACT
CeO₂ / polishing material inquiries
Email[email protected]
Technical Siteceriumoxide.org
Corporate Sitewww.expolish.com
Registered AddressRoom 618, Block B, Building 7, No. 616 Dongwei Road, Hezhuang Subdistrict, Qiantang District, Hangzhou, Zhejiang, China
注册地址浙江省杭州市钱塘区河庄街道东围路616号7幢B座618室
Technical note: this page is an educational and technical reference synthesized from the cited public sources. Commercial specifications must be confirmed against the current TDS, COA and SDS for the exact supplied grade.