Magnesium sulfate

Magnesium sulfate or magnesium sulphate is a chemical compound, a salt with the formula MgSO₄, consisting of magnesium cations Mg²⁺ (20.19% by mass) and sulfate anions SO2−4. It is a white crystalline solid, soluble in water but not in ethanol.

Magnesium sulfate

Magnesium sulfate hexahydrate
Anhydrous magnesium sulfate
Epsomite (Magnesium sulfate heptahydrate)
Names
IUPAC name Magnesium sulfate
Other names Epsom salt (Magnesium sulfate heptahydrate) English salt Bitter salts Bath salt
Identifiers
CAS Number	7487-88-9 (anhydrous) Y 14168-73-1 (monohydrate) Y 24378-31-2 (tetrahydrate) Y 15553-21-6 (pentahydrate) Y 13778-97-7 (hexahydrate) Y 10034-99-8 (heptahydrate) Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:32599 Y CHEBI:31795 (heptahydrate)
ChEMBL	ChEMBL2021423 N ChEMBL3989857 (heptahydrate)
ChemSpider	22515 Y
DrugBank	DB00653 Y
ECHA InfoCard	100.028.453
EC Number	231-298-2
KEGG	C12505 (heptahydrate)
PubChem CID	24083
RTECS number	OM4500000
UNII	ML30MJ2U7I Y E2L2TK027P (monohydrate) Y SK47B8698T (heptahydrate) Y
CompTox Dashboard (EPA)	DTXSID6042105
InChI InChI=1S/Mg.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 Y Key: CSNNHWWHGAXBCP-UHFFFAOYSA-L Y InChI=1/Mg.8H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 Key: CSNNHWWHGAXBCP-NUQVWONBAQ
SMILES [Mg+2].[O-]S([O-])(=O)=O
Properties
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 (undecahydrate)
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 product (Ksp)	738 (502 g/L)
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)
Structure
Crystal structure	monoclinic (hydrate)
Pharmacology
ATC code	A06AD04 (WHO) A12CC02 (WHO) B05XA05 (WHO) D11AX05 (WHO) V04CC02 (WHO)
Hazards
NFPA 704 (fire diamond)	1 0 0
Related compounds
Other cations	Beryllium sulfate Calcium sulfate Strontium sulfate Barium sulfate Iron(II) sulfate Copper(II) sulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Magnesium sulfate is usually encountered in the form of a hydrate MgSO₄·nH₂O, for various values of n between 1 and 11. The most common is the heptahydrate MgSO₄·7H₂O, known as Epsom salt, which is a household chemical with many traditional uses, including bath salts.

The main use of magnesium sulfate is in agriculture, to correct soils deficient in magnesium (an essential plant nutrient because of the role of magnesium in chlorophyll and photosynthesis). The monohydrate is favored for this use; by the mid 1970s, its production was 2.3 million tons per year. The anhydrous form and several hydrates occur in nature as minerals, and the salt is a significant component of the water from some springs.