Iron III Chloride, Ferric Chloride, Iron 3 Chloride, Ferric Chloride Anhydrous, Iron Trichloride, Ferric Trichloride, Floresmartis, 7705-08-0

IRON(III) CHLORIDE (FeCl₃)

1. Chemical Identity and Material Classification

• Chemical Name: Iron(III) Chloride, Ferric Chloride, Iron Trichloride

• Synonyms: Ferric Trichloride, Flores Martis, Floresmartis, Iron Perchloride

• CAS Number: 7705-08-0 (anhydrous); 10025-77-1 (hexahydrate)

• Molecular Formula: FeCl₃

• Molecular Weight: 162.20 g/mol (anhydrous); 270.30 g/mol (hexahydrate)

• EC Number: 231-729-4

• MDL Number: MFCD00011005

• RTECS Number: LJ9100000

2. Chemical Structure and Molecular Characteristics

• Structure (solid, anhydrous): Layered structure (BiI₃ type) – hexagonal crystal system

• Structure (gas phase, >400°C): Dimeric (Fe₂Cl₆) – two FeCl₄ tetrahedra sharing an edge

• Coordination geometry (solid): Octahedral (each Fe surrounded by 6 Cl)

• Oxidation state of iron: +3 (stable, strong oxidizer)

• Fe–Cl bond length (solid): ~2.45 Å

• Magnetic moment (solid): 5.90 μB (high-spin d⁵ configuration)

3. Physical Properties

3.1 General Physical Properties (Anhydrous)

3.2 Thermal Properties

4. Solubility Behavior (g/100 g solvent, 20°C unless noted)

5. Aqueous Solution Chemistry

6. Production Methods

6.1 Direct Chlorination of Iron (Industrial Standard – Anhydrous)

• Reaction: 2Fe (s) + 3Cl₂ (g) → 2FeCl₃ (s)

• Process: Iron turnings or scrap in vertical reactor → chlorine gas passed upward → exothermic reaction at 500–700°C → FeCl₃ vapor condensed

• Yield: ~95–98%

• By-products: None (closed system)

• Energy requirement: Highly exothermic (ΔH = -800 kJ/mol)

6.2 Hydrochloric Acid Method (Solution Production)

• Reaction (step 1): Fe + 2HCl → FeCl₂ + H₂

• Reaction (step 2): 2FeCl₂ + Cl₂ → 2FeCl₃

• Process: Iron filings + HCl → FeCl₂ solution → chlorination with Cl₂ gas → FeCl₃ solution

• Typical concentration achieved: Up to 60% w/w FeCl₃ solution

6.3 One-Step Chlorination (Wet Process)

• Reaction: 2Fe + 3Cl₂ → 2FeCl₃ (in water medium)

• Process: Chlorine gas bubbled through water containing iron turnings

• Advantage: Direct production of solution without separate FeCl₂ step

6.4 From Iron Oxide (Alternative)

• Reaction: Fe₂O₃ + 6HCl → 2FeCl₃ + 3H₂O

• Application: Where high-purity iron oxide is available

7. Redox Properties and Etching Mechanism (PCB Industry)

7.1 Standard Reduction Potentials

7.2 Copper Etching Reaction (PCB Etching)

• Reaction: 2FeCl₃ + Cu → 2FeCl₂ + CuCl₂

• Net ionic: 2Fe³⁺ + Cu (s) → 2Fe²⁺ + Cu²⁺

• Standard cell potential: E°cell = 0.43 V (thermodynamically favorable)

• Reaction rate: Fast (seconds to minutes depending on concentration and temperature)

• By-product: CuCl₂ (soluble)

7.3 Etching Parameters (Typical)

8. Electrochemical Parameters (Corrosion and Etching)

9. Application Areas – PCB Etching and Metal Processing

9.1 Printed Circuit Board (PCB) Etching (Primary Application)

9.2 Water and Wastewater Treatment

9.3 Heavy Metal Removal from Wastewater

• Mechanism: Co-precipitation with Fe(OH)₃

• Target metals: Arsenic (As), chromium (Cr), lead (Pb), cadmium (Cd)

• Removal efficiency: >95% for arsenic at Fe:As ratio of 10:1

9.4 Chlorination and Organic Synthesis Catalyst

10. Application Areas – Other Industries

10.1 Dye and Textile Industry

10.2 Photography and Printing

10.3 Pharmaceutical and Nutritional

10.4 Mining and Metallurgy

10.5 Construction

11. Comparison with Other Etchants/Coagulants

12. Product Forms and Specifications

12.1 Available Forms

12.2 Quality Specifications (Anhydrous, Technical Grade)

12.3 Quality Specifications (Aqueous Solution, 40% w/w)

13. Analytical Methods

13.1 Iron(III) Determination (Redox Titration – Iodometric)

13.2 Iron(II) Determination (Titration with KMnO₄)

13.3 Iron Determination (ICP-OES or AAS)

14. Safety and Toxicology

15. Safety Precautions and Personal Protective Equipment (PPE)

• Hazards:

  • Corrosive – causes severe skin burns and eye damage

  • Harmful if swallowed (H302)

  • Reacts with water (exothermic)

  • Decomposes at high temperature to toxic Cl₂ gas

• Reactivity:

  • Incompatible with: strong oxidizing agents, alkali metals (K, Na – explosive mixtures), water (exothermic)

  • Corrosive to most metals (especially stainless steel at high concentrations)

  • Compatible storage materials: glass, PTFE, polypropylene, PVC (for limited time), Hastelloy C

• PPE (mandatory):

  • Chemical-resistant gloves (nitrile, neoprene, or PVC; minimum 0.4 mm thickness, EN 374)

  • Chemical splash goggles (EN 166) or full face shield

  • Protective clothing (apron or suit, acid-resistant)

  • Rubber boots (for large spills)

  • Respiratory protection (if dust or mist present – P2 filter)

• Engineering controls:

  • Local exhaust ventilation (LEV) for powder handling or heated solutions

  • Eyewash stations and safety showers within immediate vicinity

• First aid:

  • Inhalation: Remove to fresh air; if breathing difficulty, administer oxygen; seek medical attention

  • Skin contact: Remove contaminated clothing; wash with copious water for at least 15 minutes; seek medical attention

  • Eye contact: Rinse with water for 15–20 minutes, lifting eyelids; seek immediate medical attention

  • Ingestion: Rinse mouth; do NOT induce vomiting; give milk or water; seek immediate medical attention

16. Environmental Fate and Disposal

17. Storage and Shelf Life

• Storage conditions:

  • Cool, dry, well-ventilated area (10–30°C)

  • Keep tightly closed in original packaging (anhydrous is highly hygroscopic)

  • Store away from water, moisture, and incompatible materials (alkali metals, oxidizers)

  • Store away from combustible materials (can support combustion)

  • Do not store near food or feed

  • Use corrosion-resistant shelving (plastic-coated or stainless steel)

• Shelf life:

  • Anhydrous (sealed): 24 months (if kept dry – otherwise deliquesces rapidly)

  • Hexahydrate (sealed): 36 months

  • Solution (40%, pH <1): 12 months (may precipitate Fe(OH)₃ if pH rises)

• Degradation indicator:

  • Anhydrous: Formation of yellow/brown liquid (deliquescence – water absorption)

  • Solution: Formation of reddish-brown precipitate (Fe(OH)₃)

18. Transport Information

19. Synonyms, Standards Compliance, and Why Choose Iron(III) Chloride?

Synonyms

• English: Ferric chloride, Iron trichloride, Ferric trichloride, Flores martis, Iron(III) chloride

• Other languages:

  • Turkish: Demir(III) klorür, Ferrik klorür

  • German: Eisen(III)-chlorid

  • French: Chlorure de fer(III)

  • Spanish: Cloruro férrico

Standards Compliance

Why Choose Iron(III) Chloride? (Technical Summary)

• High copper etching rate (10–30 μm/min): Fastest among common PCB etchants

• Low cost: Economical for large-scale PCB manufacturing and water treatment

• Regenerable etching bath: Fe²⁺ can be reoxidized to Fe³⁺ with Cl₂, H₂O₂, or electrolysis

• Effective coagulant for water treatment: Wide pH range (5–8), excellent phosphate removal

• Strong Lewis acid catalyst: Used in organic synthesis (chlorination, Friedel-Crafts)

• Highly soluble (up to 92 g/100 mL water): Allows concentrated solutions for high reaction rates

• Well-established production: Global availability, multiple grades (anhydrous, hexahydrate, solution)

• Versatile oxidizer: Used for desulfurization of gases, metal leaching, and wastewater treatment

• Limitation note: Highly corrosive – requires specialized handling equipment (glass-lined, Hastelloy C, or PVC/PP for solutions). Hygroscopic – anhydrous form deliquesces rapidly in air. Generates iron-containing sludge in water treatment (disposal required).

20. Sectoral Suitability Summary Table

This TDS is prepared in compliance with ISO 11014-1 format and is intended for PCB manufacturing engineers, water treatment specialists, chemical process engineers, laboratory technicians, and procurement professionals. Certificates of Analysis (CoA), Safety Data Sheets (SDS), etching rate test reports, and sample validation reports are available upon request.