Magnesium bromide

Last updated
Magnesium bromide [1]
Magnesium-bromide-xtal-layer-3D-bs-17.png
Magnesium-bromide-xtal-3D-bs-17.png
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.029.246 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/2BrH.Mg/h2*1H;/q;;+2/p-2 Yes check.svgY
    Key: OTCKOJUMXQWKQG-UHFFFAOYSA-L Yes check.svgY
  • InChI=1/2BrH.Mg/h2*1H;/q;;+2/p-2
    Key: OTCKOJUMXQWKQG-NUQVWONBAY
  • [Mg+2].[Br-].[Br-]
Properties
  • MgBr2 (anhydrous)
  • MgBr2·6H2O (hexahydrate)
Molar mass 184.113 g/mol (anhydrous)
292.204 g/mol (hexahydrate)
Appearancewhite 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)
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)
−72.0·10−6 cm3/mol
Structure
Rhombohedral, hP3
P-3m1, No. 164
octahedral
Thermochemistry
70 J/(mol·K)
Std molar
entropy
(S298)
117.2 J·mol−1·K−1
−524.3 kJ·mol−1
Hazards
NFPA 704 (fire diamond)
1
0
0
Safety data sheet (SDS) External SDS
Related compounds
Other anions
Other cations
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Magnesium bromide is a chemical compound of magnesium 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]

Contents

Synthesis

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]

Uses

Magnesium bromide is used as a Lewis acid catalyst in some organic synthesis, e.g., in aldol reaction. [6] In organosilicon 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]

Related Research Articles

<span class="mw-page-title-main">Bromine</span> Chemical element, symbol Br and atomic number 35

Bromine is a chemical element with the symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig and Antoine Jérôme Balard, its name was derived from the Ancient Greek βρῶμος (bromos) meaning "stench", referring to its sharp and pungent smell.

<span class="mw-page-title-main">Magnesium chloride</span> Inorganic salt: MgCl2 and its hydrates

Magnesium chloride is an inorganic compound with the formula MgCl2. It forms hydrates MgCl2·nH2O, where n can range from 1 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of which occur in nature, have a variety of practical uses. Anhydrous magnesium chloride is the principal precursor to magnesium metal, which is produced on a large scale. Hydrated magnesium chloride is the form most readily available.

<span class="mw-page-title-main">Hydrogen bromide</span> Chemical compound

Hydrogen bromide is the inorganic compound with the formula HBr. It is a hydrogen halide consisting of hydrogen and bromine. A colorless gas, it dissolves in water, forming hydrobromic acid, which is saturated at 68.85% HBr by weight at room temperature. Aqueous solutions that are 47.6% HBr by mass form a constant-boiling azeotrope mixture that boils at 124.3 °C. Boiling less concentrated solutions releases H2O until the constant-boiling mixture composition is reached.

<span class="mw-page-title-main">1,4-Dioxane</span> Chemical compound

1,4-Dioxane is a heterocyclic organic compound, classified as an ether. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. The compound is often called simply dioxane because the other dioxane isomers are rarely encountered.

In polyatomic cations with the chemical formula PR+
4
. These cations have tetrahedral structures. The salts are generally colorless or take the color of the anions.

<span class="mw-page-title-main">Aluminium bromide</span> Chemical compound

Aluminium bromide is any chemical compound with the empirical formula AlBrx. Aluminium tribromide is the most common form of aluminium bromide. It is a colorless, sublimable hygroscopic solid; hence old samples tend to be hydrated, mostly as aluminium tribromide hexahydrate (AlBr3·6H2O).

<span class="mw-page-title-main">Lithium bromide</span> Chemical compound

Lithium bromide (LiBr) is a chemical compound of lithium and bromine. Its extreme hygroscopic character makes LiBr useful as a desiccant in certain air conditioning systems.

<span class="mw-page-title-main">Hypobromous acid</span> Chemical compound

Hypobromous acid is a weak, unstable acid with chemical formula of HOBr. It is mainly produced and handled in an aqueous solution. It is generated both biologically and commercially as a disinfectant. Salts of hypobromite are rarely isolated as solids.

The Schlenk equilibrium, named after its discoverer Wilhelm Schlenk, is a chemical equilibrium taking place in solutions of Grignard reagents and Hauser bases

<span class="mw-page-title-main">Grignard reagent</span> Organometallic compounds used in organic synthesis

A Grignard reagent or Grignard compound is a chemical compound with the general formula R−Mg−X, where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride Cl−Mg−CH3 and phenylmagnesium bromide (C6H5)−Mg−Br. They are a subclass of the organomagnesium compounds.

<span class="mw-page-title-main">Titanium tetrabromide</span> Chemical compound

Titanium tetrabromide is the chemical compound with the formula TiBr4. It is the most volatile transition metal bromide. The properties of TiBr4 are an average of TiCl4 and TiI4. Some key properties of these four-coordinated Ti(IV) species are their high Lewis acidity and their high solubility in nonpolar organic solvents. TiBr4 is diamagnetic, reflecting the d0 configuration of the metal centre.

<span class="mw-page-title-main">Calcium bromide</span> Chemical compound

Calcium bromide is the name for compounds with the chemical formula CaBr2(H2O)x. Individual compounds include the anhydrous material (x = 0), the hexahydrate (x = 6), and the rare dihydrate (x = 2). All are white powders that dissolve in water, and from these solutions crystallizes the hexahydrate. The hydrated form is mainly used in some drilling fluids.

<span class="mw-page-title-main">Allyl bromide</span> Chemical compound

Allyl bromide (3-bromopropene) is an organic halide. It is an alkylating agent used in synthesis of polymers, pharmaceuticals, synthetic perfumes and other organic compounds. Physically, allyl bromide is a colorless liquid with an irritating and persistent smell, however, commercial samples are yellow or brown. Allyl bromide is more reactive but more expensive than allyl chloride, and these considerations guide its use.

The Kulinkovich reaction describes the organic synthesis of cyclopropanols via reaction of esters with dialkyldialkoxytitanium reagents, generated in situ from Grignard reagents bearing hydrogen in beta-position and titanium(IV) alkoxides such as titanium isopropoxide. This reaction was first reported by Oleg Kulinkovich and coworkers in 1989.

<span class="mw-page-title-main">Strontium bromide</span> Chemical compound

Strontium bromide is a chemical compound with a formula SrBr2. At room temperature it is a white, odourless, crystalline powder. Strontium bromide imparts a bright red colour in a flame test, showing the presence of strontium ions. It is used in flares and also has some pharmaceutical uses.

Methylmagnesium chloride is an organometallic compound with the general formula CH3MgCl. This highly flammable, colorless, and moisture sensitive material is the simplest Grignard reagent and is commercially available, usually as a solution in tetrahydrofuran.

<span class="mw-page-title-main">Barium bromide</span> Chemical compound

Barium bromide is the chemical compound with the formula BaBr2. It is ionic in nature.

<span class="mw-page-title-main">Nickel(II) bromide</span> Chemical compound

Nickel(II) bromide is the name for the inorganic compounds with the chemical formula NiBr2(H2O)x. The value of x can be 0 for the anhydrous material, as well as 2, 3, or 6 for the three known hydrate forms. The anhydrous material is a yellow-brown solid which dissolves in water to give blue-green hexahydrate (see picture).

Dimethylmagnesium is an organomagnesium compound. It is a white pyrophoric solid. Dimethylmagnesium is used in the synthesis of organometallic compounds.

Samarium(III) bromide is a crystalline compound of one samarium and three bromine atoms with the chemical formula of SmBr3. Samarium(III) bromide is a dark brown powder at room temperature. The compound has a crystal structure isotypic to that of plutonium(III) bromide.

References

  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
  3. 1 2 3 Gruyter, W. Concise Encyclopedia Chemistry, Walter de Gruyter & Company: Berlin, 1993; 612
  4. 1 2 Lewis, R.J. Hawley’s Condensed Chemical Dictionary, 15th ed.; John Wiley &Sons Inc.:New York, 2007; 777
  5. Fischer, Reinald; Görls, Helmar; Meisinger, Philippe R.; Suxdorf, Regina; Westerhausen, Matthias (2019). "Structure–Solubility Relationship of 1,4‐Dioxane Complexes of Di(hydrocarbyl)magnesium". Chemistry – A European Journal. 25 (55): 12830–12841. doi:10.1002/chem.201903120. PMC   7027550 . PMID   31328293.
  6. Evans, David A.; Tedrow, Jason S.; Shaw, Jared T.; Downey, C. Wade (2002). "Diastereoselective Magnesium Halide-Catalyzed anti-Aldol Reactions of Chiral N-Acyloxazolidinones". Journal of the American Chemical Society. 124 (3): 392–393. doi:10.1021/ja0119548. PMID   11792206.
  7. 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.
  8. Bouzide, Abderrahim (2002). "Magnesium Bromide Mediated Highly Diastereoselective Heterogeneous Hydrogenation of Olefins". Organic Letters. 4 (8): 1347–50. doi:10.1021/ol020032m. PMID   11950359.
  9. 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. S2CID   94416902.