Cerium Hydroxide, Cerous Hydroxide, Cerium (III) Hydroxide, 15785-09-8

CERIUM HYDROXIDE (CERIUM(III) HYDROXIDE) 

Chemical Name: Cerium(III) Hydroxide / Cerous Hydroxide
CAS Number: 15785-09-8
EC Number: 239-898-7
UN Number: 3077 (Environmentally hazardous substance)

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

CHEMICAL STRUCTURE AND DESCRIPTION:

Cerium Hydroxide (Ce(OH)₃) is the hydroxide salt of cerium in the +3 oxidation state. The compound consists of a cerium ion (Ce³⁺) coordinated by three hydroxide ions (OH⁻). It forms a hexagonal crystal structure typical of lanthanide hydroxides. Cerium Hydroxide is practically insoluble in water but readily dissolves in acids, forming cerium salts. It is a key intermediate in the production of high-purity cerium oxide (CeO₂) and other cerium compounds. Due to its ability to form gels, it is also used in various materials science applications.

Structural Features:

• Hexagonal crystal structure (lanthanide hydroxide type)

• Practically insoluble in water

• Readily dissolves in acids

• Thermally decomposes to CeO₂ upon heating

• Can form colloidal suspensions and gels

• Amphoteric character (reacts with both acids and strong bases)

2. PHYSICAL AND CHEMICAL PROPERTIES

Thermal Decomposition Reaction:
2Ce(OH)₃ → 2CeO₂ + 3H₂O (300-400°C)

Cerium Hydroxide is a white, odorless, practically water-insoluble crystalline powder with a density of approximately 3.9 g/cm³. It decomposes upon heating, converting to cerium oxide (CeO₂) in the temperature range of 300-400°C. Its extremely low solubility in water (Ksp ~2.0 × 10⁻²⁰) makes it an ideal precipitant for cerium separation processes. It exhibits amphoteric behavior, dissolving in acids to form cerium salts and showing slight solubility in strong alkalis.

3. SOLUBILITY PROFILE

Cerium Hydroxide is practically insoluble in water and organic solvents. It readily dissolves in dilute and concentrated acids, forming the corresponding cerium(III) salts (chlorides, nitrates, sulfates, etc.). It exhibits amphoteric properties, showing slight solubility in strong alkalis. This solubility profile makes it an ideal intermediate for cerium compound production and purification.

4. CHEMICAL PROPERTIES AND REACTIONS

Cerium Hydroxide is a typical rare earth hydroxide. Its extremely low solubility product constant (Ksp ~2.0 × 10⁻²⁰) makes it readily precipitatable from cerium salt solutions upon addition of alkali. Upon heating, it decomposes to cerium oxide (CeO₂). It exhibits amphoteric behavior, dissolving in acids to form salts and showing slight solubility in concentrated alkalis. Freshly precipitated Ce(OH)₃ forms a gelatinous precipitate that ages to a more crystalline form over time.

Key Chemical Reactions:

Acid Dissolution:
Ce(OH)₃ + 3HCl → CeCl₃ + 3H₂O
Ce(OH)₃ + 3HNO₃ → Ce(NO₃)₃ + 3H₂O

Thermal Decomposition:
2Ce(OH)₃ → 2CeO₂ + 3H₂O (300-400°C)

Reaction with CO₂:
2Ce(OH)₃ + 3CO₂ → Ce₂(CO₃)₃ + 3H₂O

Oxidation:
Ce(OH)₃ + H₂O₂ + 3OH⁻ → Ce(OH)₄ + 3OH⁻

5. SPECIFICATIONS (TECHNICAL AND HIGH PURITY)

Cerium Hydroxide is manufactured in various grades from technical (≥ 98%) to high purity (≥ 99.99%). High purity grades (99.99% and above) are essential for optical, electronic, and research applications where trace impurities significantly affect performance. The loss on ignition corresponds to the water content and conversion to CeO₂. Technical grades are suitable for metallurgical and general industrial applications.

6. APPLICATIONS AND INDUSTRIAL USES

6.1. Cerium Oxide (CeO₂) Production (Most Important Application)

Cerium Hydroxide is the most important intermediate precursor for CeO₂ production. Upon heating, it decomposes to cerium oxide. Its high purity and controlled precipitation properties make it ideal for producing high-purity CeO₂ for optical, catalytic, and electronic applications. The calcination process from hydroxide to oxide allows precise control over particle size and morphology.

CeO₂ Production Pathway:
Ce³⁺ salt solution → Ce(OH)₃ precipitation → Filtration → Calcination (300-400°C) → CeO₂

6.2. Research and Laboratory Applications

6.3. Nanotechnology and Advanced Materials

6.4. Electrochemical Applications

6.5. Ceramics and Glass Applications

6.6. Defense and Specialized Optics

7. ALTERNATIVE / EQUIVALENT PRODUCTS

8. SECTOR SUITABILITY TABLE

9. COMMON NAMES

• Cerium-based precipitant

• White cerium powder

• CeO₂ precursor

• Cerium hydroxide crystal

• Cerium trihydroxide

• Cerous hydroxide

• Rare earth hydroxide

10. PRODUCTION PROCESS

Reaction Equation:
Ce³⁺ + 3OH⁻ → Ce(OH)₃ ↓
or
CeCl₃ + 3NaOH → Ce(OH)₃ ↓ + 3NaCl

Production Types: Technical and high purity grades

Major Producing Countries: China, India, United States, Russia, Japan

Commercial Purity: Ranges from 98% to 99.99%

11. SAFETY AND TOXICOLOGY

SPECIAL WARNINGS: Cerium Hydroxide is generally considered of low toxicity. However, as with all chemicals, appropriate handling procedures should be followed. It may cause irritation to skin, eyes, and respiratory tract. Inhalation of dust should be avoided. The compound is not classified as carcinogenic. Environmental release should be prevented as it is classified as an environmentally hazardous substance (UN 3077) in some formulations.

12. TRANSPORT INFORMATION

Cerium Hydroxide is classified as an environmentally hazardous substance under UN 3077. Release into the environment must be prevented during transport. Proper packaging and labeling are required for international transport.

13. REGULATORY INFORMATION

Cerium Hydroxide is registered in all major industrial markets. KKDİK registration is required for use in Turkey. It is classified under customs tariff code 2846.90.00.00.19. Proper import/export documentation is required for international trade.

14. STORAGE AND HANDLING

Handling Notes:

• Avoid dust formation and inhalation

• Avoid skin and eye contact (use protective gloves and safety goggles)

• Use in well-ventilated areas

• Store away from acids and CO₂ sources

• Prevent environmental release

• Use under fume hood or with adequate ventilation

15. FIRE-FIGHTING MEASURES

Cerium Hydroxide is not a flammable substance. In case of fire, protective clothing and SCBA must be used. Thermal decomposition may release cerium oxide fumes.

16. ACCIDENTAL RELEASE MEASURES

In case of spillage, appropriate personal protective equipment must be worn. Clean up using dry methods. Environmental release must be prevented as it is classified as UN 3077.

17. FIRST AID MEASURES

Special Notes:

• Cerium hydroxides are considered of low acute toxicity

• Medical personnel should be informed about hydroxide salt exposure

• In case of ingestion, do not induce vomiting due to possible aspiration risk

18. RAW MATERIALS AND DOWNSTREAM PRODUCTS

18.1. Raw Materials (Upstream)

18.2. Downstream Products

19. QUALITY CONTROL PARAMETERS

20. SUMMARY AND CRITICAL WARNINGS

SUMMARY:

Cerium Hydroxide (Ce(OH)₃, CAS 15785-09-8) is a white to off-white, practically water-insoluble, crystalline powder. It is the hydroxide salt of cerium in the +3 oxidation state with a molecular weight of 204.13 g/mol. Its density is approximately 3.9 g/cm³ and it decomposes upon heating to cerium oxide (CeO₂) at 300-400°C. The compound has an extremely low solubility in water (Ksp ~2.0 × 10⁻²⁰) but readily dissolves in acids to form cerium salts. It exhibits amphoteric behavior with slight solubility in strong alkalis.

Its most important application is as an intermediate precursor for CeO₂ production. Thermal decomposition of cerium hydroxide yields high-purity cerium oxide, which is used in optics, catalysts, polishing applications, and automotive emissions control. It is also used in research laboratories as a precipitation agent, in nanotechnology for nanoparticle synthesis, in electrochemical applications (supercapacitor electrodes), and in ceramics and glass applications as a refractive index adjuster and surface modifier.

The compound is classified as an environmentally hazardous substance under UN 3077 and is a marine pollutant. While generally considered of low toxicity, it can cause skin, eye, and respiratory tract irritation. It should be stored in cool, dry, well-ventilated areas away from acids and CO₂ sources. Its slightly hygroscopic nature requires protection from moisture during storage. The shelf life is 24-36 months under proper storage conditions.

Key Properties:

Major Application Areas:

Key Safety Points:

• ENVIRONMENTALLY HAZARDOUS: UN 3077

• IRRITANT: Skin, eye and respiratory irritation

• SLIGHTLY HYGROSCOPIC: Protect from moisture

• REACTS WITH ACIDS: Dissolves readily, may generate heat

• REACTS WITH CO₂: Forms carbonate over time

• STORAGE: Cool, dry, well-ventilated, away from CO₂

• PROTECTIVE EQUIPMENT: Gloves, safety goggles, dust mask

• ECOTOXIC: Marine pollutant

CRITICAL WARNINGS:

1. UN 3077 CLASSIFICATION: Cerium Hydroxide is classified as an environmentally hazardous substance under UN 3077. Release into the environment during transport, storage, or disposal must be strictly prevented. It is listed as a marine pollutant.

2. CeO₂ PRECURSOR: This compound is the most important intermediate precursor for cerium oxide production. The quality of the hydroxide directly affects the properties of the final CeO₂ product, including particle size, purity, and surface area. The calcination process (300-400°C) must be carefully controlled.

3. AMPHOTERIC CHARACTER: Cerium Hydroxide exhibits amphoteric behavior, dissolving in acids to form cerium salts and showing slight solubility in strong alkalis. This property is fundamental to its use in precipitation and separation processes.

4. CO₂ SENSITIVITY: Cerium Hydroxide reacts with atmospheric carbon dioxide to form cerium carbonate. Long-term exposure to air can lead to carbonate formation, affecting purity. Store in airtight containers to prevent CO₂ absorption.

5. PRECIPITATION CHEMISTRY: Freshly precipitated Ce(OH)₃ forms a gelatinous precipitate that ages to a more crystalline form over time. This aging process affects filtration efficiency, particle size, and subsequent processing behavior. Control of aging conditions is critical for consistent product quality.

6. THERMAL DECOMPOSITION: Upon heating, Ce(OH)₃ decomposes to CeO₂ with a theoretical weight loss of approximately 20-25% (water release). This decomposition temperature (300-400°C) is lower than that of carbonate or oxalate precursors, making it energy-efficient for CeO₂ production.

7. HANDLING IN DRY CONDITIONS: While only slightly hygroscopic, prolonged exposure to moisture can lead to surface changes and handling difficulties. For moisture-sensitive applications, use in low-humidity environments.

8. CUSTOMS CLASSIFICATION: The correct customs tariff code is 2846.90.00.00.19. Correct classification is essential for international trade, with potential country-specific restrictions for rare earth compounds.

9. Ksp VALUE: The extremely low solubility product (Ksp ~2.0 × 10⁻²⁰) means that precipitation from cerium salt solutions is essentially complete under appropriate pH conditions. This makes the compound ideal for quantitative separation and purification processes.

10. COMPARISON WITH OTHER PRECURSORS: Compared to cerium carbonate or oxalate, cerium hydroxide offers lower calcination temperature and different particle morphology. The choice of hydroxide vs. other precursors depends on specific application requirements, particularly for optical-grade CeO₂ where purity and morphology are critical.

Important Disclaimer: This Technical Data Sheet (TDS) is for informational purposes only. The information provided is based on available data and is believed to be accurate. However, the user is solely responsible for determining the suitability of the product for their specific applications and for complying with all applicable regulations and safety requirements. For complete safety, handling, storage, and regulatory compliance information, always refer to the official Safety Data Sheet (SDS/MSDS) provided by the manufacturer/supplier. Users are responsible for testing the product in their own processes and applications. All local, national, and international regulations must be followed when working with Cerium Hydroxide. Due to its environmental classification and reactivity, a detailed risk assessment and handling procedure should be established prior to use.