Magnesium chloride (chemical formula: MgCl₂) is a typical ionic halide compound, consisting of one magnesium ion and two chloride ions. It is naturally present in seawater, salt lake brines, and is a by-product of salt production. This substance is highly soluble in water and prone to deliquescence. It usually exists in nature in the form of hexahydrate (MgCl₂·6H₂O).

CAS Number: 7786-30-3

EINECS Number: 232-094-6

Molecular formula:

Hydrate-free substance: MgCl₂

Hexahydrate: MgCl₂·6H₂O

Molecular weight:

Dry substance: 95.21 - 95.2

Hexahydrate: 203.31

Physical and chemical parameters

Due to the significant differences in properties between anhydrous magnesium chloride and hexahydrate magnesium chloride, the following lists the key parameters respectively:

Main advantages and features

• High solubility and reactivity: Magnesium chloride has an extremely high solubility in water (approximately 400g/L), making it an ideal raw material for salt water preparation and a chemical reaction medium.

• Hygroscopicity: Anhydrous magnesium chloride has extremely strong hygroscopic properties and is commonly used as a desiccant or to control humidity through absorption.

• Thermal decomposition characteristics: When heated, magnesium chloride hexahydrate does not simply melt but undergoes a gradual hydrolysis process, releasing hydrogen chloride gas, and ultimately decomposes into magnesium oxide or chlorinated magnesium oxide. This characteristic makes it highly applicable in the field of refractory material binders.

• Safety: Non-flammable, but it has a slight irritant effect on the eyes and respiratory tract. The median lethal dose (LD50) for rats via oral ingestion is approximately 2800mg/kg, which indicates it is a relatively low-toxic substance.

Main purpose

Magnesium chloride is a fundamental raw material in the fields of chemical engineering, construction materials, food, and environmental protection.

Industrial and chemical raw materials: Used for the production of metallic magnesium (by electrolytic melting of anhydrous magnesium chloride), potassium magnesium fertilizer, magnesium fluoride and other magnesium-based chemicals.

Environmental protection and road maintenance: As a de-icing agent and dust suppressant, it utilizes its hygroscopic property to keep the road surface moist. Additionally, due to its lower corrosiveness to metals compared to sodium chloride, it is widely used in certain areas.

Building materials industry: It is the core raw material for producing magnesite products (such as fireproof boards, ventilation ducts, manhole covers, and floors), which react with magnesium oxide (MgO) and water to form chloromagnesium oxide cement with high strength and rapid setting.

Food industry: Used as a food additive.

• Bean product coagulant: The main component of "salt brine" used in making traditional tofu.

• Nutritional fortifier: Used in dairy products and infant foods to supplement magnesium (limit: 3000 - 7000 mg/kg for dairy products).

Other applications:

• Refrigeration: Prepared as chilled brine, used as an indirect cooling medium.

• Fire extinguisher: Used for preparing fire-fighting agents.

• Medicine: As an excipient for medicinal purposes or used in the preparation of disinfectants.

Specification standards (taking the hexahydrate as an example)

The common indicators for analytical purity (AR) and chemical purity (CP) in industry are as follows:

Storage and Transportation Recommendations

• Storage conditions: It must be stored in a cool, dry, and well-ventilated warehouse, avoiding direct sunlight. Due to its high susceptibility to moisture absorption, the packaging must be tightly sealed to prevent moisture absorption and clumping.

• Isolation requirements: It should be stored separately from oxidants and must not be mixed together.

• Operational protection: Operators must wear dust masks, chemical safety goggles and rubber protective clothing to prevent dust inhalation.