Magnesium Sulfate

magnesium sulfate [mag′nē·zē·əm ′səl‚fāt]

(inorganic chemistry)

MgSO₄Colorless crystals with a bitter, saline taste; soluble in glycerol; used in fireproofing, textile processes, ceramics, cosmetics, and fertilizers.

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Magnesium Sulfate 

MgSO₄, a salt; colorless crystals. Density, 2.66 g/cm³. Decomposes into MgO, SO₂, and O₂ at 1100°-1200°C.

Solubility in water, 25.2 percent (by weight) at 20°C. It forms crystalline hydrates with one, two, three, four, five, six, seven, and 12 water molecules; the crystallization of MgSO₄.7H₂O from aqueous solutions takes place at room temperature. Magnesium sulfate occurs naturally as kieserite, MgSO₄.H₂O, and epsomite MgSO₄«7H₂O (Epsom salt). It interacts with salts of alkali metals to form double salts, among them langbeinite, K₂SO₄.2MgSO₄; astrakanite, Na₂SO₄.MgSO₄.4H₂O; polyhalite, K₂SO₄.MgSO₄.2CaSO₄.2H₂O; and kainite, KCL MgSO₄.3H₂O (all of which occur in nature).

Magnesium sulfate is extracted from natural ocean brines and solid salt deposits. It is used to prepare SO₂ in the production of H₂SO₄, and also in the manufacture of magnesia cement, in the textile industry as a filler and mordant, in the paper industry as a filler, and in agriculture.

In medicine, magnesium sulfate serves as a tranquilizer, antispasmodic, laxative, and cholagogue. It is available in prepared solution (for intramuscular or intravenous injection) or in powder form.