Epsom salts

Magnesium sulfate

Anhydrous magnesium sulfate
Epsomite (heptahydrate)
Names
IUPAC name Magnesium sulphate
Other names Epsom salt (heptahydrate) English salt Bitter salts Bath salts
Identifiers
CAS Number	7487-88-9 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 (Jmol)	Interactive image
ChEBI	CHEBI:32599 Y
ChEMBL	ChEMBL1200456 N
ChemSpider	22515 Y
DrugBank	DB00653 Y
ECHA InfoCard	100.028.453
E number	E518 (acidity regulators, ...)
PubChem	24083
RTECS number	OM4500000
UNII	ML30MJ2U7I Y
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.H2O4S/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 (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 71 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)
Structure
Crystal structure	monoclinic (hydrate)
Pharmacology
ATC code	A06AD04 (WHO) A12CC02 (WHO) B05XA05 (WHO) D11AX05 (WHO) V04CC02 (WHO)
Hazards
Safety data sheet	External MSDS
NFPA 704	0 1 0
Related compounds
Other cations	Beryllium sulfate Calcium sulfate Strontium sulfate Barium sulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

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. The overall global annual usage in the mid-1970s of the monohydrate was 2.3 million tons, of which the majority was used in agriculture.

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.

It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.

Magnesium sulfate is a common mineral pharmaceutical preparation of magnesium, commonly known as Epsom salt, used both externally and internally. Magnesium sulfate is highly water-soluble and solubility is inhibited with lipids typically used in lotions. Lotions often employ the use of emulsions or suspensions to include both oil and water-soluble ingredients. Hence, magnesium sulfate in a lotion may not be as freely available to migrate to the skin nor to be absorbed through the skin, hence both studies may properly suggest absorption or lack thereof as a function of the carrier (in a water solution vs. in an oil emulsion/suspension). Temperature and concentration gradients may also be contributing factors to absorption.