Magnesium Bromide(MgBr2) Properties(25 Facts You Should Know)

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MgBr2 is a halogenated magnesium complex with two Bromine atoms. Let us discuss some more facts about MgBr2 in this article.

MgBr2 has trigonal omega structure. MgBr2 is highly hygroscopic and has a hexagon shape. MgBr2 is prepared by the reaction of hydrobromic acid with magnesium oxide. MgBr2 is electrolytic as it conducts electricity in the molten state.

The following article will discuss some more basic facts about MgBr2, like the IUPAC name, molar mass, molar density, melting point, and crystal structure.

Magnesium Bromide IUPAC Name

The IUPAC name of MgBr2 is Magnesium Dibromide.

Magnesium Bromide Chemical Formula

The chemical formula for Magnesium Bromide is MgBr2. The atomic symbol for Magnesium is Mg, and for Bromide, it is Br. The ratio of Magnesium ion and Bromide ion in MgBr2 is 1:2.

Magnesium Bromide CAS Number

7789-48-2 is the CAS number of Magnesium Bromide.

Magnesium Bromide Chemspider ID

74219 is the Chemspider ID of Magnesium Bromide.

Magnesium Bromide Chemical Classification

The chemical classification of MgBr2 is given below:

  • MgBr2 is a lewis acid.
  • MgBr2 is an ionic compound.
  • MgBr2 is an inorganic magnesium salt.
  • MgBr2 is an magnesium halide.
  • MgBr2 is an inorganic bromide.

Magnesium Bromide Molar Mass

The molar mass of Magnesium Bromide is 184.113 g/mol. The compound consists of one magnesium cation with an atomic mass of 24.305u, and the atomic mass for bromide is 79.9 g/mol. The total molar mass is calculated by adding the mass of one magnesium ion and two bromide ions i,e; 24.305 + (2*79.9) = 184.113 g/mol.

Magnesium Bromide Color

The color of Magnesium Bromide is white or off-white.

Magnesium Bromide Molar Density

The molar density of Magnesium Bromide is 0.020 mol/cm3, as the density of MgBr2 is 3.72 g/cm3. To calculate the molar density, the density is divided by the molar mass as 3.72/184.113 = 0.020 mol/cm3.

Magnesium Bromide Melting Point

The melting point of Magnesium Bromide is 711o C or 1,312o F or 984 K. The melting point of MgBr2 is extremely high due to its crystalline structure and strong ionic forces, which bind the atoms very strongly with each other.

Magnesium Bromide Boiling Point

The boiling point of Magnesium Bromide is 1,412o C or 2,574o F, or 1,685 K. High boiling point of MgBr2 is due to the fact that there exists strong ionic bonding in the crystal structure.

Magnesium Bromide State At Room Temperature

Magnesium Bromide exists as a very deliquescent crystalline solid at room temperature as the melting and boiling points of the crystal are above 500o C. The ionic bonds are so strong that it remains in the solid form at room temperature as it requires a lot of energy to break these bonds.

Magnesium Bromide Ionic Bond

The Magnesium Bromide compound consists of two ionic bonds. Both the bromide ions share charges with the central magnesium metal and form two ionic bonds as they are oppositely charged. Magnesium ions donate their two electrons to two bromide ions, and bond formation occurs.

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Bonding in MgBr2

Magnesium Bromide Ionic Radius

The ionic radius of the Mg-Br bond in the Magnesium Bromide structure is 2.70Ao. Ionic radius is calculated for those compounds in which bond formation occurs based on charged ions. Atoms donate and accept electrons, and thus the formation of ionic bonds takes place.

Magnesium Bromide Electronic Configurations

The electronic configuration describes the system of electron distribution in an atom’s shells. Let us have a look at the electronic configuration of Magnesium Bromide in detail.

The electronic configuration of Mg and Br is [Ne]3s2 and [Ar] 3d10 4s2 4p6, respectively. Magnesium ion contains 2 valence electrons, and bromide ion contains 7 valence electrons. Each bromide ion contains three lone pairs and one bond pair, while each magnesium ion consists of only two bonding electrons.

MgBr2 Oxidation State

The oxidation state of magnesium ions in Magnesium Bromideis +2, while the oxidation state of two bromide ions is -1. The magnesium ions donate one electron each to two bromide ions and gain a +2 charge. At the same time, the bromide ions accept an electron from the magnesium ion and acquire a -1 charge.

MgBr2 Acidity

Magnesium Bromide is a weak lewis acid. The two bromide ions pull out the electron density from the magnesium ions. Hence, it can accept electrons due to its electropositive nature.

Is Magnesium Bromide Odourless?

Magnesium Bromide is an odorless compound.

Is Magnesium Bromide Paramagnetic?

Paramagnetism is a property of compounds, metals, or ions that contain unpaired electrons in their valence shell. Let us discuss if Magnesium Bromide is paramagnetic or not.

Magnesium Bromide is non-paramagnetic as it does not contain any unpaired electrons. The valence shell of magnesium consists of two paired electrons donated to form ionic bonds with two bromide ions, and the valence shell of magnesium becomes empty.

Magnesium Bromide Hydrates

The anhydrous form of magnesium bromide is less stable than the hydrated form, which behaves as a weak lewis acid. The magnesium bromide hydrates are –

  • Magnesium Dibromide Hexahydrate (MgBr2.6H2O)
  • Magnesium Dibromide Decahydrate(MgBr2.6H2O)

Magnesium Bromide Crystal Structure

Magnesium Bromide exists in a rhombohedral crystal-type structure with P-3m1, No.164, as the space group. The MgBr2 structure exists in layered 2D form. The crystal structure is similar to the CdI2 crystal system. The lattice parameters of MgBr2 are a = 3.88Ao , b = 3.88Ao , c = 7.03Ao , α = 90.00 º, β = 90.00 º and ɣ = 120.00 º.

Magnesium Bromide Polarity and Conductivity

  • Magnesium Bromide is a polar molecule. The molecular geometry of MgBr2 is bent. The direction of the dipole is from Mg+2 to Br–.
  • Magnesium Bromide conducts electricity in a liquid or molten state only. MgBr2 is highly soluble in water. In the liquid state, the compound dissociates into ions and conducts electricity.

Magnesium Bromide Reaction With Acid

Magnesium Bromide is an acid, and though weak, its reaction with acid is not much pronounced. The Grignard reagent is a well-known reagent used to interconvert several organic compounds.

Magnesium Bromide Reaction With Base

Magnesium Bromide reacts with a base like sodium carbonate(Na2CO3) to produce a white precipitate of magnesium carbonate(MgCO3) and sodium bromide(NaBr) salt.

MgBr2 (aq) + Na2CO3 (aq) = MgCO3 (s) + 2NaBr (aq)

Magnesium Bromide Reaction With Oxide

Magnesium Bromide reacts with several oxides to form magnesium oxide and corresponding salt. For example, when MgBr2 reacts with sodium oxide(Na2O), it produces magnesium oxide and sodium bromide salt.

MgBr2 + Na2O = MgO + NaBr

Magnesium Bromide Reaction With Metal

Magnesium Bromide is used in the presence of metal as a catalyst in many organic reactions. Grignard reagent, a well-known reagent, is used to interconvert several organic compounds.

Conclusion

Magnesium Bromide is present in many natural minerals, such as bischofite, seawater, natural springs, and carnallite. Magnesium Bromide is used as a catalyst in some reactions. Magnesium bromide is used as a reagent in many organic reactions. Magnesium Bromide is used in the manufacturing of nanowires and superconductors.