Praseodymium Nitrate Tetrahydrate, Praseodymium Nitrate Hydrate, Praseodymium Trinitrate Tetrahydrate, 15878‑77‑0

Praseodymium Nitrate Tetrahydrate, Praseodymium Nitrate Hydrate, Praseodymium Trinitrate Tetrahydrate, 15878‑77‑0

PRASEODYMIUM(III) NITRATE TETRAHYDRATE 

Chemical Name: Praseodymium(III) Nitrate Tetrahydrate / Praseodymium Trinitrate Tetrahydrate
CAS Number: 15878-77-0
EC Number: 239-988-9
HS Code: 283429

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

2. CHEMICAL STRUCTURE AND EXPLANATION

Chemical Structure and Bonding:

Praseodymium(III) Nitrate Tetrahydrate is an ionic compound composed of one Praseodymium (Pr³⁺) cation and three Nitrate (NO₃⁻) anions. Praseodymium is in the +3 oxidation state (trivalent) in this compound. The molecule contains four molecules of water of crystallization. The characteristic green color is due to the Pr³⁺ ion's f-f electronic transitions in the visible region.

Molecular Formula Representation:

Pr(NO₃)₃·4H₂O

This formula indicates the following structure:

• 1 Praseodymium ion (Pr³⁺): Central metal atom.

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

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

Crystal Structure and Ionic Arrangement:

In the crystal structure, the Pr³⁺ ion is coordinated by oxygen atoms from nitrate groups and water molecules (typically 9-coordinate). Nitrate ions act as bridges between praseodymium centers. The four 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:

        Pr³⁺   NO₃⁻   H₂O
          \     /       /
           Pr(NO₃)₃ · 4H₂O
          /     \       \
        NO₃⁻   NO₃⁻   H₂O

(An ionic crystal lattice composed of 1 Pr³⁺ ion, 3 NO₃⁻ ions, and 4 water molecules)

Structural Properties:

Dehydration (Loss of Water upon Heating):

Praseodymium Nitrate Tetrahydrate loses water sequentially when heated:

Pr(NO₃)₃·4H₂O → Pr(NO₃)₃·xH₂O → Pr(NO₃)₃ (anhydrous)

At higher temperatures, the nitrate groups decompose to form praseodymium oxide (Pr₆O₁₁ or Pr₂O₃) and nitrogen oxides (NOx).

3. PHYSICAL AND CHEMICAL PROPERTIES

Important Physical Notes:

• Praseodymium Nitrate has a characteristic green color due to the Pr³⁺ ion's f-f electronic transitions.

• It 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 green liquid.

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

• It 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 praseodymium oxide.

First, dehydration:
Pr(NO₃)₃·4H₂O → Pr(NO₃)₃ + 4H₂O (approximately 60-200°C)

Then, thermal decomposition:
4 Pr(NO₃)₃ → Pr₆O₁₁ + 12 NO₂ + O₂ (high temperature, >600°C)

2. Reaction with Bases (Precipitation):

Praseodymium hydroxide precipitates, which can be used as an intermediate in praseodymium oxide production.

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

3. Dissolution and Hydrolysis in Water:

Hydrolysis of praseodymium ions causes the solution to become acidic.

Pr³⁺ + H₂O ⇌ Pr(OH)²⁺ + H⁺

4. Precipitation with Ammonia:

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

5. Oxidation to Pr⁴⁺:

Pr³⁺ can be oxidized to Pr⁴⁺ under strong oxidizing conditions:

Pr³⁺ → Pr⁴⁺ + e⁻

This property is important for certain optical and catalytic applications.

6. Precipitation with Oxalate:

2 Pr(NO₃)₃ + 3 (NH₄)₂C₂O₄ → Pr₂(C₂O₄)₃ ↓ + 6 NH₄NO₃

5. APPLICATIONS AND INDUSTRIAL USES

5.1. Optical Glass and Materials (Most Important Application)

Praseodymium compounds are widely used in optical glass production for their distinctive green coloration and high refractive index properties. Praseodymium-doped glasses are used in specialty optics and lighting applications.

5.2. Phosphors and Luminescent Materials

Praseodymium compounds are used in phosphors and luminescent materials for their green emission and unique optical properties.

5.3. Catalyst Applications

5.4. Advanced Ceramics and Materials

5.5. Rare Earth Synthesis and Laboratory

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:

Praseodymium(III) Nitrate Tetrahydrate (Pr(NO₃)₃·4H₂O, CAS 15878-77-0) is an inorganic salt composed of one Praseodymium (Pr³⁺) and three Nitrate (NO₃⁻) ions, containing four molecules of water of crystallization. It appears as a green crystalline solid, is highly soluble in water and ethanol, and is hygroscopic (moisture-absorbing). The green color is characteristic of Pr³⁺ ions.

Its most critical application is in optical glass production for green coloration and specialty optical properties. It is also used in phosphors and luminescent materials (green emission), catalysts, advanced ceramics, and as a laboratory reagent for rare earth chemistry research.

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. The green color may fade or change if the compound absorbs significant moisture.

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: Contains four molecules of water of crystallization. Different hydrate forms have different molecular weights. The specific hydrate form must be confirmed when ordering and using the product. Stoichiometric calculations must account for the water content.

5. Structure and Purity: High purity (≥ 99.9%) is critical for optical, phosphor, and catalyst applications. Even trace amounts of other rare earth elements (particularly neodymium, lanthanum, cerium) can affect optical properties, green coloration, or catalytic performance. Purity specifications must be carefully verified for optical applications.

6. Color Stability and Optical Properties: The green color of praseodymium compounds depends on the oxidation state (Pr³⁺). Oxidation to Pr⁴⁺ can change the color and optical properties. Care must be taken during processing to maintain the desired oxidation state for optical applications.

7. 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.

8. 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.

9. Environmental Precautions: As a water-soluble salt, release into the environment (particularly water sources) must be prevented. Praseodymium 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.

10. 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.

11. Special Warning for Optical Glass Applications: For optical glass production, the nitrate decomposition conditions (temperature, atmosphere, heating rate) are critical to achieve the desired coloration and optical properties. Incomplete nitrate decomposition can cause bubbles or discoloration in the glass. The presence of other rare earth impurities can shift the green color or reduce optical clarity.

12. Special Warning for Phosphor Applications: The green emission from Pr³⁺ depends on the host crystal structure and local environment. Synthesis conditions must be carefully optimized to achieve efficient luminescence. Residual nitrates can quench luminescence and should be completely decomposed during synthesis.

13. Recycling and Waste: Praseodymium is a critical raw material. Recovery and recycling of praseodymium from waste optical glasses, phosphors, and other materials should be considered to ensure sustainable supply and reduce environmental impact.

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 Praseodymium(III) Nitrate Tetrahydrate.