Magnesium Sulfate Anhydrous (MgSO₄) 7487-88-9

Magnesium Sulfate Anhydrous (MgSO₄) is a white, highly hygroscopic powder with a molecular weight of 120.37 g/mol. Unlike the heptahydrate form (Epsom salt), it contains no water of crystallization. This gives it strong moisture-absorbing properties, making it an effective desiccant for organic synthesis and laboratory applications.

Anhydrous magnesium sulfate (MgSO₄) contains no crystal water and has approximately 20% magnesium content. It is highly hygroscopic and primarily used as a desiccant. Heptahydrate magnesium sulfate (MgSO₄·7H₂O, Epsom salt) contains seven water molecules and has approximately 9.9% magnesium content. It is the most common form, used for agriculture, bath salts, and pharmaceutical applications where high solubility and ease of handling matter.

Anhydrous magnesium sulfate is one of the most commonly used drying agents in organic chemistry laboratories. It is added directly to organic solutions after extraction to absorb dissolved water. The anhydrous powder forms the heptahydrate as it absorbs moisture, and the hydrated solid can be removed by filtration. It is preferred for its high capacity, fast action, and chemical inertness toward most organic compounds.

Yes, anhydrous magnesium sulfate is an effective high-analysis magnesium fertilizer. It contains approximately 20% magnesium, more than double the concentration of the heptahydrate form. It is used to correct magnesium deficiency in crops where a concentrated magnesium source is needed, and is particularly suitable for soil application or blending into compound fertilizers.

Anhydrous magnesium sulfate must be stored in tightly sealed containers in a cool, dry place. It is highly hygroscopic and will rapidly absorb moisture from the air, converting to the heptahydrate form if left exposed. Keep containers sealed when not in use and protect from humidity. Under proper storage conditions in sealed containers, shelf life is up to 24 months.