Cerium dioxide
[CAS# 1306-38-3]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Oxides of rare earth metals, yttrium or scandium
• Name: Cerium dioxide
• Synonyms: Cerium(IV) oxide
• Molecular Formula: CeO₂
• Molecular Weight: 172.11
• CAS Registry Number: 1306-38-3
• EC Number: 215-150-4
• SMILES: O=[Ce]=O

Properties

• Density: 7.132
• Melting point: 2600 ºC
• Water solubility: insoluble

Safety Data

• Hazard Symbols: GHS07;GHS08 Warning
• Hazard Statements: H302-H373-H413
• Precautionary Statements: P260-P264-P270-P273-P301+P317-P319-P330-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Acute toxicity	Acute Tox.	4	H302
Acute toxicity	Acute Tox.	3	H331
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	1	H330

Discovory and Applicatios

Cerium dioxide was first isolated and characterized in the early 19th century, when cerium metal was discovered. It is primarily extracted from cerium minerals through purification processes. The compound exists in a variety of forms, including nanocrystalline powders and bulk materials, each of which exhibits unique physical and chemical properties that are critical to its applications. Cerium dioxide is a versatile oxide with a fluorite crystal structure in which the cerium ion exists in the +4 oxidation state. This structure gives ceria its exceptional catalytic, optical, and electronic properties. It is insoluble in water, but dissolves in acids to form cerium salts, which can be used in aqueous environments for a variety of chemical reactions and applications.

The primary use of ceria is in catalysis, where its unique redox properties facilitate a wide range of catalytic reactions. Ceria-based catalysts are used in automotive catalytic converters to reduce harmful emissions by converting carbon monoxide (CO) and hydrocarbons (HC) into less toxic compounds. In addition, ceria can be used in industrial processes, such as fuel refining, to improve efficiency and reduce environmental impact.

The optical properties of ceria make it valuable in a variety of technological applications. Ceria nanoparticles are used as UV absorbers in sunscreen formulations and cosmetics to protect the skin from harmful UV radiation. Ceria-based electrolytes and electrodes are integral components of SOFCs, enabling efficient conversion of chemical energy into electrical energy at low operating temperatures. Ceria's refractive index and transparency in the visible and near-infrared regions make it suitable for optical coatings, lenses, and glass polishing.

In biomedical and environmental sciences, ceria shows promising applications: ceria nanoparticles are used as contrast agents in medical imaging techniques, including magnetic resonance imaging (MRI) and fluorescence imaging, due to their biocompatibility and ability to enhance imaging resolution. Ceria nanoparticles exhibit catalytic activity in water treatment processes, promoting the degradation of organic pollutants and contaminants in aquatic environments.

Ceria's nanoscale properties drive innovation in materials science: ceria nanoparticles are used in nanotechnology for their unique mechanical, electrical, and thermal properties, helping to advance advances in sensors, energy storage devices, and nanocomposites. Ceria-based ceramics and coatings have enhanced mechanical strength, thermal stability, and corrosion resistance, making them ideal for high-temperature applications in the aerospace, automotive, and semiconductor industries.

References

2009. Cerium oxide nanoparticles prepared in self-assembled systems. Advances in Colloid and Interface Science, 147-148.
DOI: 10.1016/j.cis.2008.10.004

2016. Cerium Oxide Nanoparticles: A Potential Medical Countermeasure to Mitigate Radiation-Induced Lung Injury in CBA/J Mice. Radiation Research, 185(5).
DOI: 10.1667/rr14261.1

2016. Single particle ICP-MS method development for the determination of plant uptake and accumulation of CeO2 nanoparticles. Analytical and Bioanalytical Chemistry, 408(20).
DOI: 10.1007/s00216-016-9565-1