FeCl₂ (Iron(II) Chloride) Comprehensive Guide: Properties, Applications, and Reliable Sources for Purchase in 2026
FeCl₂ (Ferrous Chloride, CAS 7758-94-3) is a divalent iron salt that is highly soluble in water and commonly exists as a pale green solution with a commercial concentration of 15–30%. FeCl₂ is widely used in industrial wastewater treatment (flocculation, heavy metal removal, phosphorus control), the textile and dyeing industry (dye fixative, dyeing catalyst), electroplating (Cr⁶⁺ removal), Fenton systems (advanced oxidation), and as an intermediate in chemical synthesis. Loc Thien Chemicals—a FeCl₂ manufacturer with 6 warehouses nationwide and a fleet of specialized tanker trucks—supplies industrial-grade FeCl₂ along with a Certificate of Analysis (COA) and Material Safety Data Sheet (MSDS) for each shipment.
This article is a comprehensive guide to FeCl₂ for plant operators and industrial chemical buyers: physical and chemical properties, technical specifications, 5 main applications, the flocculation mechanism, a comparison of powder and liquid forms, safe storage, and reputable suppliers.
5 Key Points to Remember:
- FeCl₂ (CAS 7758-94-3) — a pale green solution that is highly soluble in water and readily oxidizes to Fe³⁺ if not stored in a sealed container.
- 5 key applications: wastewater treatment, textile dyeing, electroplating, Fenton process, chemical synthesis — always require a jar test before scaling up to production.
- Not a 1:1 substitute for FeCl₃: FeCl₂ contains Fe²⁺ (reducing agent, Fenton reaction), while FeCl₃ contains Fe³⁺ (stronger flocculation in many water systems).
- 15–30% liquid form is the most common, available in 30L cans, 200L drums, 1,000L tanks, or tank trucks.
- B2B Purchases: Get a quote within 15 minutes via our hotline at 0979 891 929; COA/MSDS provided per batch.
What is FeCl₂? Physical and Chemical Properties
FeCl₂ (Iron(II) Chloride, Ferrous Chloride) is an inorganic salt compound consisting of Fe²⁺ and two Cl⁻ ions, with the formula FeCl₂ and CAS number 7758-94-3. This chemical is highly soluble in water and exists in three forms: the anhydrous form (white/light gray powder), the tetrahydrate form FeCl₂·4H₂O (light green crystals), and a commercial liquid solution ranging from 15–30% (characteristic pale green color). In the Vietnamese market, FeCl₂ is primarily supplied as a solution and is used in the wastewater treatment, textile dyeing, electroplating, and chemical synthesis industries.
Physical Properties
Anhydrous FeCl₂ has a molar mass of ~126.75 g/mol; the FeCl₂·4H₂O form has a molar mass of ~198.81 g/mol, a density of 1.93 g/cm³, and a melting point of 105°C. The compound is highly soluble in water and is strongly hygroscopic—the crystals readily dissolve, and the solution gradually darkens due to the oxidation of Fe²⁺ to Fe³⁺ when left exposed to air. The color of the solution serves as a quick indicator of quality: pale green indicates that Fe²⁺ is still in good condition; dark brown indicates significant oxidation.
Chemical Properties
FeCl₂ exhibits all the properties of an iron(II) salt: it is soluble in water, forming a slightly acidic solution; it is a strong reducing agent; and it is easily oxidized to Fe³⁺. Characteristic reaction with alkali: FeCl₂ + 2NaOH → Fe(OH)₂↓ + 2NaCl — a bluish-white precipitate that rapidly turns reddish-brown upon exposure to air. It is precisely the reducing power of Fe²⁺ that forms the basis for three key industrial applications: the reduction of Cr⁶⁺ to Cr³⁺ in electroplating wastewater treatment, acting as a catalyst in the Fenton reaction with H₂O₂ to generate ·OH radicals, and serving as a reducing agent in organic synthesis.
| Criterion | FeCl₂ (Iron II) | FeCl₃ (Iron III) |
|---|---|---|
| Iron state | Fe²⁺ | Fe³⁺ |
| CAS Number | 7758-94-3 | 7705-08-0 |
| Solution Color | Pale green | Brown / yellowish-brown |
| Primary Role | Flocculation, reduction, Fenton reaction | Strong flocculation |
| Optimal flocculation pH | 7.0–9.0 | 5.5–8.0 |
| Is 1:1 substitution possible? | No — jar test required | No |
FeCl₂ Technical Specifications Table
The table below summarizes the technical specifications for FeCl₂ in solution—the form most widely used in industry. The data for each batch is verified by the accompanying Certificate of Analysis (COA).
| Category | Technical Specifications |
|---|---|
| Product Name | FeCl₂ (Ferrous Chloride) |
| Chemical Formula | FeCl₂ (anhydrous) / FeCl₂·4H₂O (hydrated) |
| CAS Number | 7758-94-3 |
| Molar Mass | ~126.75 g/mol (anhydrous) / ~198.81 g/mol (4H₂O) |
| Appearance | Pale green, transparent liquid |
| Commercial Concentration | 15–30% w/w FeCl₂ (as specified in the COA for each batch) |
| Density | ~1.15–1.35 g/mL depending on concentration |
| Solution pH | Slightly acidic (pH ≈ 2–4) |
| Solubility | Completely soluble in water |
| Packaging | 30L plastic cans · 200L drums · 1,000L IBC tanks · Tank trucks |
| Documentation | COA · MSDS/SDS · VAT invoice |
5 Main Applications of FeCl₂
Each of the applications listed below requires jar-test to verify dosage and efficacy before production-scale deployment.
1. Industrial Wastewater Treatment
FeCl₂ is a common coagulant in industrial wastewater treatment systems. The Fe²⁺ ion hydrolyzes to form Fe(OH)₂ flocs with a large surface area, which adsorb and carry away suspended particles, a portion of the COD, and color from the wastewater. In addition to flocculation, FeCl₂ reduces toxic Cr⁶⁺ to the less toxic Cr³⁺—which is particularly important for electroplating wastewater. For textile and dyeing wastewater and phosphorus-rich wastewater, FeCl₂ is often considered in combination with PAC or FeCl₃ to optimize costs and sludge volume.
2. Textile and Dyeing Industry
In textile dyeing, FeCl₂ plays a dual role: as a mordant that fixes dyes to fabric fibers and as a catalyst that improves colorfastness. When combined with tannins, FeCl₂ forms stable black and blue-black complexes on cellulose fibers (cotton, linen, hemp). For synthetic fibers, FeCl₂ strengthens the dye-fiber bond, reducing color fading after multiple wash cycles. Dosage must be strictly controlled—excess Fe²⁺ causes color dulling on light-colored fabrics.
3. The Electroplating Industry
FeCl₂ is used in the wastewater treatment step following chrome plating: Fe²⁺ reduces Cr⁶⁺ (soluble chromate/dichromate, which is highly toxic) → Cr³⁺ (which readily precipitates as Cr(OH)₃ when the pH is raised). The molar ratio of Fe²⁺ to Cr⁶⁺ and the pH are established by each plant’s SOP based on actual testing. Additionally, FeCl₂ is used in formulas for cleaning metal surfaces prior to plating.
4. The Fenton System — Advanced Oxidation
The Fenton system (Fe²⁺ + H₂O₂) is an effective AOP method for treating wastewater containing organics that are difficult to biodegrade, such as azo dyes, pharmaceutical residues, and pesticides. Fe²⁺ catalyzes the decomposition of H₂O₂ to form ·OH radicals (oxidation potential 2.80 V)—which attack non-selectively, break aromatic rings, and mineralize pollutants. Three key parameters: the Fe²⁺:H₂O₂ ratio, pH (2.5–4.0), and reaction time. “Off-the-shelf” formulas are often unsuitable—jar tests or pilot studies are required for each facility.
5. Chemical Synthesis
FeCl₂ is an intermediate in the synthesis of organoiron compounds, as a polymerization catalyst, and in the production of iron oxide pigments and magnetic materials. The reducing properties of Fe²⁺ are utilized in the synthesis of pharmaceutical intermediates (reduction of nitro groups to amines). FeCl₂ is also a precursor for the production of other iron salts and certain surface treatment chemicals.
The Flocculation Mechanism of FeCl₂ in Wastewater Treatment
FeCl₂ coagulates through the formation of Fe(OH)₂ precipitates in three stages: hydrolysis, flocculation, and sedimentation. First, Fe²⁺ undergoes hydrolysis and reacts with natural alkalinity (HCO₃⁻, CO₃²⁻) or added alkali (NaOH, Ca(OH)₂): Fe²⁺ + 2OH⁻ → Fe(OH)₂↓. Fe(OH)₂ colloidal particles have a large surface area and carry a positive charge—they adsorb negatively charged colloidal particles (clay, colloidal organic matter, microorganisms) through charge neutralization and bridging mechanisms. Finally, the neutralized particles flocculate into large sediment flocs and settle by gravity, making them easy to separate by sedimentation or flotation.
Comparison of FeCl₂ vs. PAC vs. FeCl₃: FeCl₂ (pH 7.0–9.0) offers the advantage of reducing properties for wastewater containing Cr⁶⁺ or requiring Fe²⁺ for the Fenton process. PAC forms flocs quickly and produces less sludge, but it lacks reducing properties and typically has a higher cost per kilogram of active ingredient. FeCl₃ has stronger flocculation and a wider pH range (5.5–8.0) but cannot replace Fe²⁺ in reduction and Fenton applications. The final choice depends on jar tests and total operating costs.
FeCl₂ in Powder and Liquid Forms — Pros and Cons
FeCl₂ powder: high active ingredient concentration (60–100%); reduces long-distance shipping costs; remains stable when sealed. Disadvantages: requires a mixing tank, stirring, and labor to dissolve; prone to absorbing moisture and clumping if the packaging is left open.
Liquid FeCl₂ (15–30%): The most common form—direct metering pump, reducing labor and errors. Disadvantages: higher shipping costs (since it includes water), and requires storage tank space. Plants consuming >5–10 metric tons/month should opt for tanker trucks to optimize logistics.
| Criterion | FeCl₂ powder | FeCl₂ liquid (15–30%) |
|---|---|---|
| Active Ingredient Content | High (60–100%) | 15–30% |
| Shipping Costs | Lower | Higher |
| Ready to Use | Must be dissolved | Direct injection |
| Storage | Prone to moisture absorption and caking | Stable in sealed containers |
| Packaging | 25-kg bags | 30-L cans, 200-L drums, 1,000-L tanks, tanker trucks |
Storage and Safety Instructions
FeCl₂ is a corrosive chemical—full PPE is required: chemical-resistant goggles, butyl/neoprene gloves, chemical-resistant coveralls, and safety shoes. If it comes into contact with skin or eyes: rinse with clean water for at least 15 minutes; seek medical attention if irritation persists. Ingestion causes damage to the gastrointestinal mucosa and affects the liver and kidneys—seek emergency medical attention immediately. Refer to the MSDS/SDS for the shipment for all emergency situations.
Key storage principle: limit exposure to air to prevent Fe²⁺ from oxidizing to Fe³⁺. Store in sealed HDPE or composite containers in a dry, cool, shaded area, away from direct sunlight. Absolute incompatibilities: alkali metals/alkaline earth metals, strong bases (NaOH, KOH), strong oxidizing agents (concentrated H₂O₂, KMnO₄, HNO₃) — risk of exothermic reactions or the formation of toxic chlorine gas. Check the color periodically: light green = good; dark brown = requires reevaluation.
Lộc Thiên — FeCl₂ Manufacturer
Loc Thien Chemicals is a manufacturer of FeCl₂ with a nationwide infrastructure, serving hundreds of factories in key industrial parks. Its capabilities are substantiated by concrete evidence:
1. Network of 6 warehouses nationwide: Warehouse 1 — Mỹ Xuân, Bà Rịa–Vũng Tàu; Warehouse 2 — Long Thành, Đồng Nai; Warehouse 3 — Tân Đông Hiệp B Industrial Park, Dĩ An, Bình Dương; Warehouse 4 — Hòa Khánh Industrial Park, Đà Nẵng; Warehouse 5 — Ô Mô Industrial Park, Can Tho; Warehouse 6 — Dai Dong - Hoan Son Industrial Park, Bac Ninh. This network ensures fast delivery to all industrial parks across the three regions.
2. A fleet of 20 specialized tanker trucks: We actively transport liquid FeCl₂ directly to customers’ storage tanks. The tanker trucks undergo regular maintenance and meet chemical transport safety standards.
3. COA/MSDS for Each Batch: Each batch shipped from the factory is accompanied by a COA (actual concentration, specific gravity, pH, appearance, impurities) and an MSDS/SDS. Compare the COA with the product’s appearance upon receipt—a light green color is an indicator of quality.
4. Technical Consulting: Assistance with selecting FeCl₂/FeCl₃, advice on coagulation based on actual wastewater characteristics, and guidance on comparative jar tests. Customers with long-term contracts receive periodic quality inspections between batches.
Frequently Asked Questions About FeCl₂
Is FeCl₂ toxic? What precautions should be taken when handling it?
FeCl₂ is corrosive and toxic if it comes into direct contact with the skin or is ingested. Skin: irritation, rash, itching. Eyes: burning pain, corneal damage. Ingestion: damage to the gastrointestinal mucosa; effects on the liver and kidneys. Always wear full PPE and consult the MSDS for the shipment.
What’s the quickest way to tell FeCl₂ and FeCl₃ apart?
Based on color: FeCl₂ is pale green (Fe²⁺), while FeCl₃ is brown or yellowish-brown (Fe³⁺). They can also be distinguished by their CAS numbers (7758-94-3 vs. 7705-08-0) or by the NaOH reaction: FeCl₂ → forms a blue-white precipitate that turns brown; FeCl₃ → forms a reddish-brown precipitate immediately.
Where can I buy FeCl₂ at a good price and with consistent quality?
Purchase from manufacturers or suppliers that provide a Certificate of Analysis (COA) and Material Safety Data Sheet (MSDS) for each batch, with clearly identified warehouses and the capacity to deliver to industrial parks. Loc Thien Chemicals — 6 warehouses nationwide, 20 dedicated tanker trucks — supplies liquid FeCl₂ (15–30%) with COA/MSDS; receive a B2B quote within 15 minutes via our hotline at 0979 891 929.
Can FeCl₂ be used to treat wastewater from the textile and dyeing industry?
Yes, in two roles: (1) flocculation to remove suspended solids, COD, and color from residual dyes; (2) as a source of Fe²⁺ for the Fenton reaction to oxidize azo dyes and refractory organic compounds. Dosage and pH must be determined via jar testing on actual samples—there is no universal formula.
How much does FeCl₂ cost? Is the price publicly listed?
The price of FeCl₂ is not publicly listed because it depends on concentration, quantity, packaging type (cans, drums, IBCs, or tank trucks), and shipping distance. To receive an accurate quote within 15 minutes, contact our hotline at 0979 891 929 or visit our website at hoachatlocthien.com.
Get a FeCl₂ quote in 15 minutes
Do you need FeCl₂ for wastewater treatment, textile dyeing, electroplating, or chemical synthesis? Get a quick, accurate quote with all necessary documentation.
Hotline: 0979 891 929 | Website: hoachatlocthien.com
Have the following ready: desired concentration · estimated quantity · delivery location · packaging specifications.
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LOC THIEN INVESTMENT AND DEVELOPMENT CO., LTD.
- Address: 452/6B Provincial Road 10, Binh Tri Dong Ward, Binh Tan District, Ho Chi Minh City
- Phone: 028 6269 5669 - 028 6269 5662
- Hotline: 0979 891 929
- Website: hoachatlocthien.com