How to Write Magnesium Chloride: A Comprehensive Guide for Industrial Buyers

For procurement managers, chemical engineers, and logistics coordinators sourcing magnesium chloride, precision in written communication is non-negotiable. A single missing detail in how you write magnesium chloride — whether it’s the hydration state, CAS number, or purity base — can lead to receiving hexahydrate flakes when your process demands anhydrous powder, or industrial-grade material when food-grade is required. In this guide, we break down exactly how to correctly write magnesium chloride in purchase orders, safety data sheets, technical specifications, and regulatory filings, ensuring your sourcing is error-free and your operations run smoothly.

Why the Correct Notation of Magnesium Chloride Matters in Industrial Procurement

Magnesium chloride isn’t a single, monolithic chemical. It exists as anhydrous MgCl₂ (a highly hygroscopic powder), as the hexahydrate MgCl₂·6H₂O (crystalline flakes), and as liquid brine solutions at various concentrations. Each form has distinct physical properties, handling requirements, and end-use suitability. When buyers simply write “magnesium chloride” on a purchase order, suppliers are left to guess. That guesswork can result in:

• Receiving hexahydrate flakes for a magnesium metal production line that requires anhydrous powder, leading to moisture contamination and off-spec metal.
• Using technical-grade hexahydrate in food coagulation (tofu production) where only food-grade material with E511 certification is permitted.
• Ordering brine when a fireproofing board manufacturer needs dry powder for precise dry-mix formulations.

Precision in writing magnesium chloride specifications eliminates these risks. It aligns technical, commercial, and regulatory expectations, and it positions you as a meticulous, knowledgeable buyer in the eyes of reliable suppliers like Hailei Chemical’s magnesium chloride product line.

Understanding the Chemical Identity: How to Write Magnesium Chloride in Different Forms

The Molecular Formula: MgCl₂ and Hydration States

The backbone of any correct magnesium chloride notation is the chemical formula. For the anhydrous form, simply write MgCl₂. This denotes one magnesium atom bonded to two chlorine atoms. When water molecules are incorporated into the crystal structure, the formula changes. The most common industrial form is hexahydrate, written as:

MgCl₂·6H₂O (note the interpunct ·, not a full stop or x).

Never write “MgCl2*6H2O” or “MgCl2.6H2O” in formal documentation — the interpunct is the IUPAC standard. If your system cannot insert the interpunct, the text alternative “magnesium chloride hexahydrate” is acceptable. For procurement clarity, always pair the formula with the full chemical name: magnesium chloride hexahydrate (MgCl₂·6H₂O).

Common Trade Names, Synonyms, and CAS Numbers

To avoid ambiguity, always include the appropriate CAS registry number. This is critical because many intermediates in the magnesium chloride production chain have similar names. The key CAS numbers are:

• Anhydrous magnesium chloride: 7786-30-3
• Magnesium chloride hexahydrate: 7791-18-6

For food-grade applications, also include the E number E511. On a purchase order, writing “Magnesium Chloride Hexahydrate (CAS 7791-18-6), E511 food grade” leaves zero room for misinterpretation. Similarly, in shipping documents, using the proper UN number (not required as magnesium chloride is not classified as hazardous for transport under UN Model Regulations) and the correct technical name aligns with international trade compliance.

How to Write Magnesium Chloride Specifications for Purchase Orders and RFQs

This is where the phrase “how to write magnesium chloride” becomes most practical. A well-structured specification line item transforms a vague request into a tight commercial requirement. Below is a template adaptable for different procurement scenarios.

For hexahydrate flakes (de-icing, dust control, industrial uses):

Magnesium Chloride Hexahydrate Flakes, MgCl₂·6H₂O, CAS 7791-18-6. Purity: 46.0% MgCl₂ minimum (as MgCl₂ on dry basis). Insoluble matter: ≤0.1%. pH (5% solution): 7.0–9.0. Particle size: 90% passing 4.75 mm. Packaging: 1000 kg big bag with PE liner. Origin: China.

For anhydrous powder (metal production, chemical synthesis):

Magnesium Chloride Anhydrous Powder, MgCl₂, CAS 7786-30-3. Purity: ≥98% MgCl₂. Moisture: ≤0.5%. Iron (Fe): ≤20 ppm. Heavy metals (as Pb): ≤10 ppm. Particle size: -80 mesh. Packaging: 25 kg vacuum-sealed PE bags in steel drums.

For liquid brine (dust control, antifreeze):

Magnesium Chloride Brine, aqueous solution. Specific gravity at 20°C: 1.30–1.33 g/cm³, corresponding to approx. 29–32% MgCl₂ by weight. pH (neat): 6.0–8.0. Clarity: clear to slightly hazy, free of suspended solids. Delivery: bulk tanker ISO container.

Notice how each line item defines the form, analytical benchmark, and packaging. This level of detail directly impacts price, logistics, and fitness-for-purpose. When you request a quote from Hailei Chemical’s magnesium chloride sales team, these written specs allow them to match the exact stock or production batch to your needs without back-and-forth clarification.

Writing Magnesium Chloride in Safety Data Sheets and Regulatory Documents

Regulatory writing demands absolute nomenclature discipline. The product identifier on the SDS (Safety Data Sheet) must match the label and shipping papers. For magnesium chloride hexahydrate, the SDS Section 1 should read: Product name: Magnesium Chloride Hexahydrate; Chemical formula: MgCl₂·6H₂O; CAS No: 7791-18-6; EC No: 232-094-6. If you are authoring internal SDS documents for your own branded formulations, copying these identifiers from your supplier’s technical data sheet ensures GHS compliance.

For GHS hazard classification, magnesium chloride hexahydrate is not classified as hazardous, but it’s still essential to write the full chemical name. Abbreviating to “MgCl solution” on a customs declaration can trigger hold-ups. On import documents, always include both the commercial name and the IUPAC designation. For shipments to the EU under REACH, the written substance name must correspond to the registered tonnage band and end-use descriptor you have communicated.

Common Mistakes When Writing Magnesium Chloride and How to Avoid Them

Even experienced buyers can slip into these costly ambiguities. Here are the most frequent pitfalls and their corrections:

• Mistake 1: Writing only “magnesium chloride” without hydration state. Fix: Always specify hexahydrate or anhydrous. The price differential can exceed 30%, and their applications rarely overlap.
• Mistake 2: Using “MgCl” instead of MgCl₂. MgCl suggests a monovalent compound that doesn’t exist; it can be misread as a typo for an unrelated chemical.
• Mistake 3: Specifying purity as “46%” without defining the basis. 46% MgCl₂ in hexahydrate flakes is standard; anhydrous material is >98% min. A 46% purity spec on anhydrous would indicate severely off-spec material.
• Mistake 4: Omitting the CAS number on regulatory forms. Customs and safety databases index chemicals by CAS. Without it, your shipment may be classified incorrectly or delayed.
• Mistake 5: Describing “magnesium chloride brine” without concentration. Brine density / %MgCl₂ directly dictates anti-icing performance and freezing point depression. A 30% brine and a 15% brine behave very differently.

Application-Specific Notation: Tailoring Magnesium Chloride Descriptions to End Use

How you write magnesium chloride also depends on the application your procurement team is serving. Aligning written specifications with end-use requirements ensures you get material that solves the operational problem, not just a generic chemical.

De-icing and Dust Control

For winter road maintenance, the specification should reference the relevant national standards (e.g., ASTM D632 for liquid de-icers). Write: Magnesium chloride hexahydrate flakes, 46% MgCl₂ min, suitable for production of 30% aqueous solution for de-icing, meeting PNS 97 Type I requirements. For dust control, the brine is often the final product applied directly. Specify specific gravity and total chlorides. Our hexahydrate flakes dissolve readily into consistent brine, an important quality parameter to include.

Fireproofing Board Manufacturing

Manufacturers of magnesium oxide (MgO) boards need magnesium chloride as a binder. Here, the written requirement must go beyond basic purity and address elements that affect board strength and durability. Typically: Magnesium chloride hexahydrate flakes, MgCl₂ min 46.0%, Sodium (Na) max 0.15%, Potassium (K) max 1.0%, CaCl₂ max 0.8%, insoluble max 0.1%. The alkali ion content is critical because it influences the molar ratio of MgO to MgCl₂ and the formation of the 5-phase crystal structure. A savvy buyer writes these trace element limits directly into the RFQ to ensure board quality.

Food Coagulant (Tofu Production)

When specifying magnesium chloride as a coagulant (nigari), the written description must include the food-grade certification. Write: Magnesium chloride hexahydrate, E511, food grade, FCC compliant, CAS 7791-18-6, heavy metals (as Pb) max 5 mg/kg, arsenic max 2 mg/kg, sulfate max 0.15%. The physical form is typically flakes or a concentrated liquid. Always reference the applicable food chemicals standard to demonstrate compliance awareness.

Magnesium Metal Production

For electrolytic production of magnesium metal, anhydrous magnesium chloride is the feedstock. The written specification drives the highest purity demands: Magnesium chloride anhydrous, MgCl₂ min 98%, MgO max 0.5%, moisture max 0.5%, Fe max 0.05%, no visible discoloration. The oxide level is tightly controlled because MgO doesn’t dissolve in the molten salt electrolyte and causes sludge. Knowing how to write magnesium chloride specs this precisely immediately signals to the supplier that you are a technical end-user, enabling better price and quality support from a producer like Hailei Chemical, an experienced exporter of high-grade magnesium chloride.

Integrating Magnesium Chloride Written Specifications into Quality Agreements

Beyond the purchase order, long-term supply agreements often include a quality annex. This is where the detailed written description becomes legally binding. The annex should include:

• Product name, synonyms, CAS, and molecular formula.
• Test parameters, spec limits, and the analytical method (e.g., titration, ICP-OES).
• Sampling procedure (number of samples per batch, composite method).
• Acceptable shelf life and storage condition requirements.
• Certificate of Analysis (CoA) format — exactly what data points will be reported.

By writing magnesium chloride into the QA agreement with rigorous detail, you build a quality assurance firewall that protects your production line from lot-to-lot variability.

How to Write Magnesium Chloride on Labels and Shipping Marks

International shipping requires clear, standardised marks. For magnesium chloride hexahydrate flakes packed in 25 kg bags, the printed label should read:

MAGNESIUM CHLORIDE HEXAHYDRATE FLAKES
MgCl₂·6H₂O, CAS 7791-18-6
Net Weight: 1000 kg
Batch No: HC20240815
Country of Origin: China
Manufacturer: Weifang Hailei Fine Chemical Co., Ltd.

For liquid brine ISO tanks, the placard should state “Magnesium Chloride Solution, X%” with the appropriate % filling. Getting this right eliminates demurrage charges from misdeclared cargo.

Conclusion: Precision in Writing Magnesium Chloride Is a Procurement Multiplier

Mastering how to write magnesium chloride is a small investment that pays large dividends: shorter sourcing cycles, reduced risk of reject material, and smoother cross-border transactions. Whether you are drafting an RFQ, a technical data sheet, or a regulatory filing, the principles are the same — include the full chemical name, correct formula notation (with hydration state), the relevant CAS number, and analytical boundaries that match your application. As a responsible supplier, Hailei Chemical encourages this level of precision because it enables us to deliver exactly the product you need, when you need it.

Ready to put your precise magnesium chloride specification into action? Contact our team today for a customized quote on magnesium chloride hexahydrate flakes, anhydrous powder, or brine solutions. Let us match your written requirements with a reliable, cost-effective supply from our ISO-certified production facilities.