Cobalt Hydroxide, Cobaltous Hydroxide, 21041-93-0

Cobalt Hydroxide, Cobaltous Hydroxide, 21041-93-0

COBALT(II) HYDROXIDE

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

CHEMICAL STRUCTURE AND DESCRIPTION:

Cobalt(II) Hydroxide (Co(OH)₂) is the hydroxide salt of cobalt in the +2 oxidation state. The compound consists of a central cobalt ion (Co²⁺) coordinated by two hydroxide ions (OH⁻). The cobalt ion has a 3d⁷ electron configuration with three unpaired electrons, making the compound paramagnetic. The blue-green color is characteristic of cobalt(II) compounds. Cobalt(II) Hydroxide is sparingly soluble in water but readily dissolves in acids. It slowly oxidizes in air to cobalt oxides. It is used as a pigment in ceramics and glass, as a catalyst in organic synthesis and electrochemical applications, and as a precursor for cobalt compounds in lithium-ion batteries. It is also used in laboratory precipitation reactions and analytical chemistry.

Structural Features:

• Central cobalt ion in +2 oxidation state (3d⁷ configuration)

• Two hydroxide ligands

• Layered structure (hydroxide layers)

• Paramagnetic (three unpaired electrons)

• Slowly oxidizes in air (Co(OH)₂ → CoOOH → Co₃O₄)

• Blue-green color (characteristic of cobalt(II) compounds)

2. PHYSICAL AND CHEMICAL PROPERTIES

3. SOLUBILITY PROFILE

4. CHEMICAL PROPERTIES AND REACTIONS

Key Chemical Reactions:

Thermal Decomposition:
Co(OH)₂ → CoO + H₂O (150-200°C)

Acid Dissolution:
Co(OH)₂ + 2HCl → CoCl₂ + 2H₂O

Oxidation (in Air):
4Co(OH)₂ + O₂ → 4CoOOH + 2H₂O (slow)

Ammonia Complex Formation:
Co(OH)₂ + 6NH₃ → Co(NH₃)₆₂

Precipitation Reaction:
Co²⁺ + 2OH⁻ → Co(OH)₂ ↓

5. APPLICATIONS AND INDUSTRIAL USES

6. SPECIFICATIONS (TYPICAL)

7. HANDLING AND STORAGE

Handling Notes:

• Avoid dust formation and inhalation

• Avoid skin and eye contact

• Use in well-ventilated areas

• Wash hands thoroughly after handling

• Keep containers tightly closed when not in use

• Protect from moisture (oxidation risk)

8. SAFETY AND TOXICOLOGY

SPECIAL WARNINGS:

• Cobalt(II) Hydroxide is classified as a suspected carcinogen and reproductive toxicant

• Avoid inhalation of dust

• Avoid contact with skin and eyes

• Use only in well-ventilated areas

• Cobalt compounds may cause allergic skin reactions

• Very toxic to aquatic life; avoid environmental release

• Slowly oxidizes in air; color change may occur during long-term storage

9. FIRST AID MEASURES

Special Notes:

• Cobalt compounds are toxic and may cause allergic reactions

• Medical personnel should be informed about cobalt compound exposure

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

10. TRANSPORT INFORMATION

11. REGULATORY INFORMATION

12. SUMMARY AND CRITICAL WARNINGS

SUMMARY:

Cobalt(II) Hydroxide (Co(OH)₂, CAS 21041-93-0) is a blue-green crystalline solid or powder with a molecular weight of 92.95 g/mol and density of approximately 3.6 g/cm³. It is sparingly soluble in water (Ksp ~2.5 × 10⁻¹⁶) but readily dissolves in acids. It slowly oxidizes in air to cobalt oxides. It is paramagnetic due to unpaired electrons in the cobalt ion.

Its most important applications include use as a blue-green pigment in ceramics and glass, as a catalyst in organic synthesis and electrochemical applications, as a precursor for cobalt compounds in lithium-ion batteries, and as a laboratory reagent in precipitation reactions and analytical chemistry.

The compound is classified as a suspected carcinogen (Category 1B) and reproductive toxicant (Category 1) . It is harmful if swallowed or inhaled, causes skin and eye irritation, may cause allergic skin reactions, and is very toxic to aquatic life. Storage should be in cool, dry, well-ventilated areas, in tightly closed containers, away from moisture and strong acids.

Key Properties:

Key Safety Points:

• CARCINOGEN: Category 1B (suspected carcinogen)

• REPRODUCTIVE TOXIN: Category 1

• HARMFUL: Harmful if swallowed or inhaled (H302, H332)

• IRRITANT: Skin and respiratory irritation (H315, H335)

• SENSITIZER: May cause allergic skin reaction (H317)

• ENVIRONMENTAL: Very toxic to aquatic life (H410)

• PROTECTIVE EQUIPMENT: Gloves, safety goggles, protective clothing, dust mask

CRITICAL WARNINGS:

1. Carcinogenicity and Reproductive Toxicity: Cobalt(II) Hydroxide is classified as Category 1B carcinogen and Category 1 reproductive toxicant. Strict exposure controls are mandatory.

2. Oxidation Sensitivity: Cobalt(II) Hydroxide slowly oxidizes in air to cobalt oxides (CoOOH, Co₃O₄). Color change and chemical transformation may occur during long-term storage. Storage in closed containers under inert atmosphere is recommended.

3. Environmental Hazard: Very toxic to aquatic life with long-lasting effects. Environmental release must be strictly prevented.

4. Acid Reactivity: Reacts with acids to form cobalt salts. Avoid contact with acids.

5. Customs Classification: The correct customs tariff code is 2822.00.00.

6. Regulatory Compliance: REACH, KKDİK, and TSCA registration requirements apply. Not permitted for food, cosmetic, or pharmaceutical applications.

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 Cobalt(II) Hydroxide. This material is strictly for industrial and research use only.