Magnesium Sulfate


Magnesium Sulfate

Magnesium sulfate is an inorganic salt (chemical compound) containing magnesium, sulfur and oxygen, with the formula MgSO4. It is often encountered as the heptahydrate sulfate mineral epsomite (MgSO4•7H2O), commonly called Epsom salt.

The monohydrate, MgSO4•H2O is found as the mineral kieserite. Anhydrous magnesium sulfate is used as a drying agent. The anhydrous form is hygroscopic (readily absorbs water from the air) and is therefore difficult to weigh accurately; the hydrate is often preferred when preparing solutions (for example, in medical preparations).

Epsom salt has been traditionally used as a component of bath salts. Epsom salt can also be used as a beauty product.

Athletes use it to soothe sore muscles, while gardeners use it to improve crops. It has a variety of other uses: for example, Epsom salt is also effective in the removal of splinters. Epsom salt is used as bath salts and for isolation tanks. Magnesium sulfate is the main preparation of intravenous magnesium.

In gardening and other agriculture, magnesium sulfate is used to correct a magnesium or sulfur deficiency in soil; magnesium is an essential element in the chlorophyll molecule, and sulfur is another important micronutrient.

FormulaMgSO4 Molar mass 120.366 g/mol Melting point 1124 °C IUPAC ID Magnesium sulfate Density2.66 g/cm³ Soluble in Water


  • Epsom salts are used as bath salts
  • Uses in Cosmetics
  • Pharmaceutical application
  • As a Fertilizer
  • Industrial application


Molecular Weight 246.47
Appearance White Crystals
Assay Min 95%
Magnesium as Mg Min 9.8%
Iron (Fe) Max 0.001%
Chloride Max 0.014%
Heavy Metal Content Max 0.0008%
Arsenic (As) Max 0.0002%
Water Insoluble Matters 0.01%