Magnesium bromide

Magnesium bromide[1]
Identifiers
CAS Number	7789-48-2 (anhydrous) ; 13446-53-2 (hexahydrate) ; 75198-45-7 ;
3D model (JSmol)	Interactive image;
ChemSpider	74219 ;
ECHA InfoCard	100.029.246
PubChem CID	522691;
UNII	2VC6P60SLN ;
CompTox Dashboard (EPA)	DTXSID7064865 ;
	InChI InChI=1S/2BrH.Mg/h21H;/q;;+2/p-2 Key: OTCKOJUMXQWKQG-UHFFFAOYSA-L ; InChI=1/2BrH.Mg/h21H;/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)	−72.0·10−6 cm3/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 (So298)	117.2 J·mol−1·K−1
Std enthalpy of; formation (ΔfH⦵298)	-524.3 kJ·mol−1
Hazards
Safety data sheet	External SDS
NFPA 704 (fire diamond)	0 1 0
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).
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	Infobox references

Magnesium bromide (MgBr₂) is a chemical compound of magnesium and bromine that is white and deliquescent. 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]

Synthesis

Magnesium bromide can be synthesized by reacting hydrobromic acid with magnesium oxide and crystallizing the product.[4] It can also be made by reacting magnesium carbonate and hydrobromic acids, and collecting the solid left after evaporation.[3]

Uses

Magnesium bromide is used as a catalyst for many reactions, the first being a solvent-free one-pot synthesis of dihydropyrimidinones, which are often used in the pharmaceutical world in medications such as calcium channel blockers and HIVgp-120-CD4 inhibitors.[5] It also has been used as a tranquilizer.[3] Magnesium bromide in combination with CH₂Cl₂ catalyzes a reaction that causes specific symmetry and chiral centers through hydrogenation of alkenes.[6] Magnesium bromide when bonded to other functional groups has shown more practical uses other than catalyzing reactions. When bonded to an ethyl group it is used for regiospecific analysis of triglycerols.[7] Magnesium bromide hexahydrate is being worked with to be used 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.[8] Magnesium bromide was used to synthesize the first stable magnesium silylenoid. A silylenoid is a compound that contains R₂SiM_X (M is metal and R is an organic moiety). Traditionally only lithium, potassium, and sodium could be used. The magnesium silylenoid is synthesized through the addition of magnesium bromide to lithium lithium methyl bromosilylenoid. The magnesium atom replaces the lithium in the complex and has a bromide attached to it. This complex is stable at room temperature.[9]

References

Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, Florida: CRC Press. pp. 4–67. ISBN 0-8493-0594-2.
Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8
Gruyter, W. Concise Encyclopedia Chemistry, Walter de Gruyter & Company: Berlin, 1993; 612
Lewis, R.J. Hawley’s Condensed Chemical Dictionary, 15th ed.; John Wiley &Sons Inc.:New York, 2007; 777
Salehi, Hojatollah; Guo, Qing‐Xiang (2004). "A Facile and Efficient One‐Pot Synthesis of Dihydropyrimidinones Catalyzed by Magnesium Bromide Under Solvent‐Free Conditions". Synthetic Communications. 34 (1): 171. doi:10.1081/SCC-120027250.
Bouzide, Abderrahim (2002). "Magnesium Bromide Mediated Highly Diastereoselective Heterogeneous Hydrogenation of Olefins". Organic Letters. 4 (8): 1347–50. doi:10.1021/ol020032m. PMID 11950359.
Ando, Y; Tomita, Y; Haba, Y. Preparation of Ethyl Magnesium Bromide for Regiospecific Analysis of Triacylglycerols Journal of Oleo Science, 2008, 57, 459
Mostashari, S. M.; Fayyaz, F. (2008). "XRD characterization of the ashes from a burned cellulosic fabric impregnated with magnesium bromide hexahydrate as flame-retardant". Journal of Thermal Analysis and Calorimetry. 92 (3): 845. doi:10.1007/s10973-007-8928-4.
Lim, Young Mook; Cho, Hyeon Mo; Lee, Myong Euy; Baeck, Kyoung Koo (2006). "A Stable Magnesium Bromosilylenoid: Transmetalation of a Lithium Bromosilylenoid by Magnesium Bromide". Organometallics. 25 (21): 4960. doi:10.1021/om060589w.

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[hand-1] Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, Florida: CRC Press. pp. 4–67. ISBN 0-8493-0594-2.

[2] Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8

[ReferenceA-3] Gruyter, W. Concise Encyclopedia Chemistry, Walter de Gruyter & Company: Berlin, 1993; 612

[l-4] Lewis, R.J. Hawley’s Condensed Chemical Dictionary, 15th ed.; John Wiley &Sons Inc.:New York, 2007; 777

[5] Salehi, Hojatollah; Guo, Qing‐Xiang (2004). "A Facile and Efficient One‐Pot Synthesis of Dihydropyrimidinones Catalyzed by Magnesium Bromide Under Solvent‐Free Conditions". Synthetic Communications. 34 (1): 171. doi:10.1081/SCC-120027250.

[6] Bouzide, Abderrahim (2002). "Magnesium Bromide Mediated Highly Diastereoselective Heterogeneous Hydrogenation of Olefins". Organic Letters. 4 (8): 1347–50. doi:10.1021/ol020032m. PMID 11950359.

[7] Ando, Y; Tomita, Y; Haba, Y. Preparation of Ethyl Magnesium Bromide for Regiospecific Analysis of Triacylglycerols Journal of Oleo Science, 2008, 57, 459

[8] Mostashari, S. M.; Fayyaz, F. (2008). "XRD characterization of the ashes from a burned cellulosic fabric impregnated with magnesium bromide hexahydrate as flame-retardant". Journal of Thermal Analysis and Calorimetry. 92 (3): 845. doi:10.1007/s10973-007-8928-4.

[9] Lim, Young Mook; Cho, Hyeon Mo; Lee, Myong Euy; Baeck, Kyoung Koo (2006). "A Stable Magnesium Bromosilylenoid: Transmetalation of a Lithium Bromosilylenoid by Magnesium Bromide". Organometallics. 25 (21): 4960. doi:10.1021/om060589w.