Gadolinium Nitrate, Gadolinium Trinitrate, Gadolinium Nitrate Hydrate, 94219‑55‑3

Gadolinium Nitrate, Gadolinium Trinitrate, Gadolinium Nitrate Hydrate, 94219‑55‑3

GADOLINIUM(III) NITRATE (HYDRATE) 

Chemical Name: Gadolinium(III) Nitrate / Gadolinium Trinitrate
CAS Number: 94219-55-3
EC Number: 305-872-3
HS Code: 283429

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

2. CHEMICAL STRUCTURE AND EXPLANATION

Chemical Structure and Bonding:

Gadolinium(III) Nitrate is an ionic compound composed of one Gadolinium (Gd³⁺) cation and three Nitrate (NO₃⁻) anions. Gadolinium is in the +3 oxidation state (trivalent) in this compound. The molecule contains a variable number of water molecules of crystallization (typically 6 molecules - hexahydrate).

Molecular Formula Representation:

Gd(NO₃)₃·6H₂O (hexahydrate form)

This formula indicates the following structure:

• 1 Gadolinium ion (Gd³⁺): Central metal atom.

• 3 Nitrate groups (NO₃⁻): Trigonal planar anions.

• 6 Water molecules (H₂O): Water of crystallization bound to the crystal lattice.

Crystal Structure and Ionic Arrangement:

In the crystal structure, the Gd³⁺ ion is coordinated by oxygen atoms from nitrate groups and water molecules (typically 9-coordinate). Nitrate ions act as bridges between gadolinium centers. The six water molecules are part of the crystal structure and impart specific thermal stability and solubility characteristics to the compound. Upon heating, these water molecules are sequentially removed (dehydration), eventually forming the anhydrous form.

Simplified Ionic Representation:

        Gd³⁺   NO₃⁻   H₂O
          \     /       /
           Gd(NO₃)₃ · 6H₂O
          /     \       \
        NO₃⁻   NO₃⁻   H₂O

(An ionic crystal lattice composed of 1 Gd³⁺ ion, 3 NO₃⁻ ions, and 6 water molecules)

Structural Properties:

Dehydration (Loss of Water upon Heating):

Gadolinium Nitrate Hydrate loses water sequentially when heated:

Gd(NO₃)₃·6H₂O → Gd(NO₃)₃·xH₂O → Gd(NO₃)₃ (anhydrous)

At higher temperatures, the nitrate groups decompose to form gadolinium oxide (Gd₂O₃) and nitrogen oxides (NOx).

3. PHYSICAL AND CHEMICAL PROPERTIES

Important Physical Notes:

• Gadolinium Nitrate is highly hygroscopic and rapidly absorbs moisture from the air, requiring special packaging and storage conditions.

• It has a low melting point (~60°C); when heated, it dissolves in its own water of crystallization, forming a clear liquid.

• It has high solubility in water and ethanol, making it suitable for various applications.

• It is not a strong oxidizer but exhibits oxidizing properties due to nitrate ions. Contact with organic materials should be avoided.

• High purity grades (≥ 99.9%) are available in rare earth element purity.

4. CHEMICAL PROPERTIES AND REACTIONS

Important Reactions:

1. Thermal Decomposition:

This reaction is the primary method used for producing gadolinium oxide.

First, dehydration:
Gd(NO₃)₃·6H₂O → Gd(NO₃)₃ + 6H₂O (approximately 60-200°C)

Then, thermal decomposition:
4 Gd(NO₃)₃ → 2 Gd₂O₃ + 12 NO₂ + 3 O₂ (high temperature, >600°C)

2. Reaction with Bases (Precipitation):

Gadolinium hydroxide precipitates, which can be used as an intermediate in gadolinium oxide production.

Gd(NO₃)₃ + 3 NaOH → Gd(OH)₃ ↓ + 3 NaNO₃

3. Dissolution and Hydrolysis in Water:

Hydrolysis of gadolinium ions causes the solution to become acidic.

Gd³⁺ + H₂O ⇌ Gd(OH)²⁺ + H⁺

4. Precipitation with Ammonia:

Gd(NO₃)₃ + 3 NH₃ + 3 H₂O → Gd(OH)₃ ↓ + 3 NH₄NO₃

5. Precipitation with Oxalate:

2 Gd(NO₃)₃ + 3 (NH₄)₂C₂O₄ → Gd₂(C₂O₄)₃ ↓ + 6 NH₄NO₃

5. APPLICATIONS AND INDUSTRIAL USES

5.1. Nuclear Technology (Most Important Application)

Gadolinium compounds are used as control rod materials in nuclear reactors due to their high neutron absorption cross-section. Gadolinium Nitrate is a precursor for these applications.

5.2. Medical Imaging (MRI Contrast Agents)

Gadolinium-based contrast agents are widely used in magnetic resonance imaging (MRI). Gadolinium Nitrate is a precursor for the synthesis of these contrast agents.

5.3. Optical and Phosphor Materials

Gadolinium compounds are used in phosphors and luminescent materials due to their special optical properties.

5.4. Advanced Ceramics and Materials

5.5. Laboratory and Research

5.6. Electronics

6. SECTORAL SUITABILITY TABLE

7. SAFETY AND TOXICOLOGY

Safety Precautions:

• Keep away from heat, sparks, and open flames.

• Store separately from combustible materials.

• Avoid dust formation.

• Work in well-ventilated areas.

• Use protective gloves, safety goggles, and dust mask.

• Wash hands thoroughly after handling.

• In case of eye contact, rinse with plenty of water for at least 15 minutes and seek medical attention.

• Avoid contact with organic materials.

8. STORAGE AND HANDLING

9. TRANSPORT AND REGULATORY INFORMATION

10. QUALITY AND PURITY

11. RAW MATERIALS AND DOWNSTREAM PRODUCTS

11.1. Raw Materials (Upstream)

11.2. Downstream Products

12. FIRST AID MEASURES

13. FIREFIGHTING MEASURES

14. ACCIDENTAL RELEASE MEASURES

15. SUMMARY AND CRITICAL WARNINGS

SUMMARY:

Gadolinium(III) Nitrate (Gd(NO₃)₃·xH₂O, CAS 94219-55-3) is an inorganic salt composed of one Gadolinium (Gd³⁺) and three Nitrate (NO₃⁻) ions, containing a variable number of water molecules of crystallization (typically hexahydrate). It appears as a white crystalline solid, is highly soluble in water and ethanol, and is hygroscopic (moisture-absorbing). It has a low melting point (~60°C) and dissolves in its own water of crystallization when heated.

Its most critical application areas include use as a neutron absorber in nuclear reactors, synthesis of MRI contrast agents for medical imaging, and production of phosphor and optical materials. It is also used in advanced ceramics, as a catalyst, and as a laboratory reagent.

Under GHS classification, it is an oxidizer and harmful (H272, H302, H315, H319). Due to nitrate ions, it exhibits oxidizing properties and must be kept away from organic/reducing substances. Due to its hygroscopic nature, it must be stored in a cool, dry environment in tightly closed packaging. Appropriate Personal Protective Equipment (PPE) must be used during handling to avoid inhalation of dust and contact with skin/eyes.

Key Properties:

CRITICAL WARNINGS:

1. Oxidizing Property: Exhibits oxidizing properties due to nitrate ions. Contact with organic materials, reducing agents, and combustible materials must be avoided. May intensify fire (H272). Therefore, it must be stored separately and away from combustible and reducing materials.

2. Hygroscopic Property and Moisture Sensitivity: Highly hygroscopic and rapidly absorbs moisture from the air. Storage and weighing operations must not be performed in humid environments. After opening, the container must be quickly resealed and storage under an inert atmosphere (nitrogen, argon) is preferred. Moisture absorption compromises weighing accuracy and stoichiometry.

3. Low Melting Point and Thermal Instability: Melts at approximately 60°C by dissolving in its own water of crystallization. This is an important property to consider during thermal processes. At higher temperatures, nitrate groups decompose, releasing toxic nitrogen oxides (NO, NO₂). Thermal processes should be conducted in well-ventilated areas or under fume hoods.

4. Hydrated Structure and Stoichiometry: The product may contain a variable number of water molecules of crystallization (typically 6H₂O). Different hydrate forms have different molecular weights. The hydration state (xH₂O) must be considered when ordering and using the product. This difference must be taken into account in stoichiometric calculations.

5. Structure and Purity: High purity (≥ 99.9%) is critical for nuclear, medical, and optical applications. Impurities from other rare earth elements (terbium, europium, samarium) directly affect the performance of end products.

6. Dust Control: The powder form can irritate the lungs if inhaled. Dust control measures must be implemented in the work area (closed systems, local exhaust ventilation) and appropriate respiratory protection (dust mask or N95/FFP2) must be used.

7. Aqueous Solution Acidity: Aqueous solutions are acidic due to hydrolysis. Appropriate protective equipment should be used when working with acidic solutions, and base solutions should be available for neutralization.

8. Environmental Precautions: As a water-soluble salt, release into the environment (particularly water sources) must be prevented. Gadolinium compounds may exhibit toxic effects in aquatic environments. Waste solutions must not be discharged into sewers and must be disposed of according to local regulations.

9. Regulatory Compliance: Registration and notification requirements under REACH and KKDİK must be observed. It is classified as Class 5.1 (Oxidizing substance) under ADR/IMDG/IATA, requiring special labeling and documentation during transport. Use in food, cosmetics, and textile sectors is strictly prohibited.

10. Special Warning for MRI Contrast Agents: Gadolinium Nitrate is a precursor used in the synthesis of MRI contrast agents. However, free gadolinium ions are toxic, so in final contrast agents, gadolinium is present in the form of chelate complexes (e.g., DTPA, DOTA). This product is not for direct medical use; it is intended only for synthesis purposes.

11. Special Warning for Nuclear Applications: Gadolinium compounds used in nuclear reactors must be of extremely high purity (nuclear grade) and with a specific isotopic composition (natural gadolinium or isotopically enriched). Compliance with these requirements must be separately confirmed with the supplier.

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 Gadolinium(III) Nitrate.