硫酸镁(脱水)

Magnesium sulfate (agriculture) Magnesium sulfate (or magnesium sulphate, Epsom salt ,Bitter salt ) is a chemical compound containing magnesium ,sulfur and oxygen,with the formula Mgso4. In its hydrated form ,the PH is 6.0(5.5-6.5).It is often encountered as the heptahydrate ,Mgso4·7H2O, commonly called Epsom salt. Anhydrous magnesium sulfate is used as a drying agent .Since the anhydrous form is hygroscopic (readily absorbs water from the air )and is therefore difficult to weigh accurately, the hydrate is often prefered when reparing solutions ,for example ,in medical preparations ,Epsom salt has been traditionally used as a component of bath salts . Anhydrous magnesium sulfate is commonly used as a desicant in organic synthesis due to its affinity for water. During work-up ,an organic phase is saturated with magnesium sulfate until it no longer forms clumps .The inorgaic sulfate salts such as sodium sulfate and calcium sulfate may also be used in the same way. Molecular MgSO4Molar mass120.415g/molAppearancewhite powderDensity2.66g/cm3Melting point1124.c(anhydrous,decomp)Solubility in water26.9g/100ml(o.c) 25.5g/100ml(20.c) solubility0.0116 g/100 mL (18 °C, ) slightly soluble inalcohol insoluble in acetone(heptahydrate)(Refractive index)1.523 (monohydrate) 1.433 (heptahydrate)StructureCrystal structuremonoclinic (hydrate)