Contents

Magnesium bromide

Magnesium bromide^[1]

Identifiers
CAS Number	7789-48-2 (anhydrous) Y 13446-53-2 (hexahydrate) N 75198-45-7 (decahydrate) N
3D model (JSmol)	Interactive image
ChemSpider	74219 Y
ECHA InfoCard	100.029.246
PubChem CID	522691
UNII	2VC6P60SLN Y
CompTox Dashboard (EPA)	DTXSID7064865
InChI InChI=1S/2BrH.Mg/h2*1H;/q;;+2/p-2 Y Key: OTCKOJUMXQWKQG-UHFFFAOYSA-L Y InChI=1/2BrH.Mg/h2*1H;/q;;+2/p-2 Key: OTCKOJUMXQWKQG-NUQVWONBAY
SMILES [Mg+2].[Br-].[Br-]
Properties
Chemical formula	MgBr2 (anhydrous) MgBr2·6H2O (hexahydrate)
Molar mass	184.113 g/mol (anhydrous) 292.204 g/mol (hexahydrate)
Appearance	white hygroscopic hexagonal crystals (anhydrous) colorless monoclinic crystals (hexahydrate)
Density	3.72 g/cm3 (anhydrous) 2.07 g/cm3 (hexahydrate)
Melting point	711 °C (1,312 °F; 984 K) 172.4 °C, decomposes (hexahydrate)
Boiling point	1,250 °C (2,280 °F; 1,520 K)
Solubility in water	102 g/(100 mL) (anhydrous) 316 g/(100 mL) (0 °C, hexahydrate)
Solubility	ethanol: 6.9 g/(100 mL) methanol: 21.8 g/(100 mL)
Magnetic susceptibility (χ)	−72.0·10−6cm3/mol
Structure
Crystal structure	Rhombohedral, hP3
Space group	P-3m1, No. 164
Coordination geometry	octahedral
Thermochemistry
Heat capacity (C)	70 J/(mol·K)
Std molar entropy (S⦵298)	117.2 J/(mol·K)
Std enthalpy of formation (ΔfH⦵298)	−524.3 kJ/mol
Hazards
NFPA 704 (fire diamond)	1 0 0
Safety data sheet (SDS)	External SDS
Related compounds
Other anions	Magnesium fluoride Magnesium chloride Magnesium iodide
Other cations	Beryllium bromide Calcium bromide Strontium bromide Barium bromide Radium bromide
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

Chemical compound

Magnesium bromide is a chemical compoundofmagnesium and bromine, with the chemical formula MgBr₂. It is white and deliquescent crystalline solid. It is often used as a mild sedative and as an anticonvulsant for treatment of nervous disorders.^[2] It is water-soluble and somewhat soluble in alcohol. It can be found naturally in small amounts in some minerals such as: bischofite and carnallite, and in sea water, such as that of the Dead Sea.^[3][4]

Magnesium bromide can be synthesized by treating with magnesium oxide (and related basic salts) with hydrobromic acid.^[4] It can also be made by reacting magnesium carbonate and hydrobromic acids, and collecting the solid left after evaporation.^[3]

As suggested by its easy conversion to various hydrates, anhydrous MgBr₂ is a Lewis acid. In the coordination polymer with the formula MgBr₂(dioxane)₂, Mg²⁺ adopts an octahedral geometry.^[5]

Magnesium bromide is used as a Lewis acid catalyst in some organic synthesis, e.g., in aldol reaction.^[6]Inorganosilicon chemistry, magnesium bromide forms adducts R₂SiXMgBr₂.^[7]

Magnesium bromide also has been used as a tranquilizer.^[3]

Magnesium bromide modifies the catalytic properties of palladium on charcoal.^[8]

Magnesium bromide hexahydrate has properties as a flame retardant. It was found that if 0.125 mol/L of magnesium bromide hexahydrate was added to a cotton material it acted as a flame retardant.^[9]