Characteristic
Magnesium sulfate is an inorganic salt with the formula MgSO4(H2O)x where 0≤x≤7. It is often encountered as the heptahydrate sulphate mineral epsomite (MgSO4·7H2O), commonly called Epsom salt.
Chemical formula:MgSO4
Molar mass:120.366 g/mol (anhydrous) 138.38 g/mol (monohydrate) 174.41 g/mol (trihydrate) 210.44 g/mol (pentahydrate) 228.46 g/mol (hexahydrate) 246.47 g/mol (heptahydrate)
Appearance:white crystalline solid
Odor:odorless
Density:2.66 g/cm3 (anhydrous) 2.445 g/cm3 (monohydrate) 1.68 g/cm3 (heptahydrate) 1.512 g/cm3 (11-hydrate)
Melting point:anhydrous decomposes at 1,124°C monohydrate:decomposes at 200°C heptahydrate decomposes at 150°C undecahydrate decomposes at 2°C
Solubility in water: anhydrous 26.9 g/100 mL (0 °C) 35.1 g/100 mL (20 °C) 50.2 g/100 mL (100 °C)
heptahydrate 113 g/100 mL (20 °C)
Solubility:1.16 g/100 mL (18°C, ether) slightly soluble in alcohol, glycerol insoluble in acetone
Magnetic susceptibility (χ):−50·10−6 cm3/mol
Refractive index (nD):1.523 (monohydrate) 1.433 (heptahydrate)
Crystal structure:monoclinic (hydrate)
Application
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.