Terbium Nitrate Pentahydrate, Terbium Nitrate Hydrate, 57584‑27‑7

Terbium Nitrate Pentahydrate, Terbium Nitrate Hydrate, 57584‑27‑7

TERBIUM(III) NITRATE PENTAHYDRATE 

Chemical Name: Terbium(III) Nitrate Pentahydrate / Terbium Trinitrate Pentahydrate
CAS Number: 57584-27-7
EC Number: 260-808-2
HS Code: 283429

1. PRODUCT IDENTIFICATION AND CHEMICAL IDENTITY

2. CHEMICAL STRUCTURE AND EXPLANATION

Chemical Structure and Bonding:

Terbium(III) Nitrate Pentahydrate is an ionic compound composed of one Terbium (Tb³⁺) cation and three Nitrate (NO₃⁻) anions. Terbium is in the +3 oxidation state (trivalent) in this compound. The molecule contains five molecules of water of crystallization. The characteristic light green color is due to the Tb³⁺ ion's f-f electronic transitions. Terbium is particularly known for its intense green luminescence, which makes it valuable for phosphor applications.

Molecular Formula Representation:

Tb(NO₃)₃·5H₂O

This formula indicates the following structure:

• 1 Terbium ion (Tb³⁺): Central metal atom.

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

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

Crystal Structure and Ionic Arrangement:

In the crystal structure, the Tb³⁺ ion is coordinated by oxygen atoms from nitrate groups and water molecules (typically 8-9 coordinate). Nitrate ions act as bridges between terbium centers. The five 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:

        Tb³⁺   NO₃⁻   H₂O
          \     /       /
           Tb(NO₃)₃ · 5H₂O
          /     \       \
        NO₃⁻   NO₃⁻   H₂O

(An ionic crystal lattice composed of 1 Tb³⁺ ion, 3 NO₃⁻ ions, and 5 water molecules)

Structural Properties:

Dehydration (Loss of Water upon Heating):

Terbium Nitrate Pentahydrate loses water sequentially when heated:

Tb(NO₃)₃·5H₂O → Tb(NO₃)₃·xH₂O → Tb(NO₃)₃ (anhydrous)

At higher temperatures, the nitrate groups decompose to form terbium oxide (Tb₄O₇ or Tb₂O₃) and nitrogen oxides (NOx).

3. PHYSICAL AND CHEMICAL PROPERTIES

Important Physical Notes:

• Terbium Nitrate has a characteristic light green color due to the Tb³⁺ ion's f-f electronic transitions. This green color is the basis for its use in green phosphors.

• 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.

• Terbium is known for its intense green luminescence, which is critical for phosphor and display technologies.

4. CHEMICAL PROPERTIES AND REACTIONS

Important Reactions:

1. Thermal Decomposition:

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

First, dehydration:
Tb(NO₃)₃·5H₂O → Tb(NO₃)₃ + 5H₂O (approximately 60-200°C)

Then, thermal decomposition:
4 Tb(NO₃)₃ → Tb₄O₇ + 12 NO₂ + O₂ (high temperature, >600°C)

2. Reaction with Bases (Precipitation):

Terbium hydroxide precipitates, which can be used as an intermediate in terbium oxide production.

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

3. Dissolution and Hydrolysis in Water:

Hydrolysis of terbium ions causes the solution to become acidic.

Tb³⁺ + H₂O ⇌ Tb(OH)²⁺ + H⁺

4. Oxidation to Tb⁴⁺:

Tb³⁺ can be oxidized to Tb⁴⁺ under strong oxidizing conditions:

Tb³⁺ → Tb⁴⁺ + e⁻

This property is important for certain optical and catalytic applications.

5. Precipitation with Oxalate:

2 Tb(NO₃)₃ + 3 (NH₄)₂C₂O₄ → Tb₂(C₂O₄)₃ ↓ + 6 NH₄NO₃

5. APPLICATIONS AND INDUSTRIAL USES

5.1. Phosphors and Luminescent Materials (Most Important Application)

Terbium compounds are critical for green phosphors used in displays, lighting, and various optical applications. The characteristic green emission of Tb³⁺ is widely utilized in consumer electronics and lighting technologies.

5.2. Optical Materials and Specialty Glass

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:

Terbium(III) Nitrate Pentahydrate (Tb(NO₃)₃·5H₂O, CAS 57584-27-7) is an inorganic salt composed of one Terbium (Tb³⁺) and three Nitrate (NO₃⁻) ions, containing five molecules of water of crystallization. It appears as a light green crystalline solid, is highly soluble in water and ethanol, and is hygroscopic (moisture-absorbing). The characteristic light green color is due to the Tb³⁺ ion's f-f electronic transitions.

Its most critical application is as a precursor for green phosphors used in displays (CRT, plasma, LED), fluorescent lamps, and scintillators. Terbium's intense green luminescence makes it essential for consumer electronics and lighting technologies. It is also used in optical materials, 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 five molecules of water of crystallization. Different hydration states 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 phosphor, optical, and catalyst applications. Even trace amounts of other rare earth elements (particularly gadolinium, europium, dysprosium) can significantly affect luminescent properties, green emission color, or catalytic activity. Purity specifications must be carefully verified for critical applications.

6. Color Stability and Optical Properties: The green luminescence of terbium compounds depends on the oxidation state (Tb³⁺) and the local crystal environment. Oxidation to Tb⁴⁺ can change the color and optical properties. Care must be taken during processing to maintain the desired oxidation state for phosphor applications. Residual nitrate can quench luminescence and should be completely decomposed.

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. Terbium 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 Phosphor Applications: The green emission from Tb³⁺ is due to the ⁵D₄ → ⁷F₅ transition. This emission is highly efficient and temperature-stable. However, the luminescence efficiency depends on the host crystal structure. Synthesis conditions (temperature, atmosphere, dopant concentration) must be carefully controlled to achieve optimal luminescent properties. Residual nitrate may affect phosphor performance and should be completely decomposed during synthesis.

12. Special Warning for Tb⁴⁺/Tb³⁺ Redox: Terbium can exist in both Tb³⁺ and Tb⁴⁺ oxidation states. For most phosphor applications, Tb³⁺ is desired. Strong oxidizing conditions during synthesis or processing can convert Tb³⁺ to Tb⁴⁺, reducing luminescence efficiency. Care must be taken to maintain the Tb³⁺ state.

13. Critical Raw Material Status: Terbium is a relatively rare and expensive rare earth element. Efficient use, recovery, and recycling of terbium-containing materials from waste phosphors, displays, and other sources should be considered to ensure sustainable supply. The nitrate form is particularly useful for solution-based processing and recovery methods.

14. Storage Warning: Due to the high cost and critical nature of terbium compounds, special attention should be paid to proper storage and inventory management. Minimize exposure to air and moisture to prevent degradation and loss of product. Color changes may indicate product degradation.

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 Terbium(III) Nitrate Pentahydrate.