MGBR2 Lewis Structure: Drawings, Hybridization, Shape, Charges, Pairs


In this article, we will discuss the mgbr2 lewis structure and its hybridization, shapes, formal charges, and uses.

MgBr2 is a chemical compound in which a magnesium atom is bonded with two bromine atoms with a molecular weight of 184.113 g/mol and exists as a white crystalline salt.

How to draw the MGBR2 lewis structure?

Before starting with the mgbr2 lewis structure, one should be familiar with the term, i.e., valence electrons.

MGBR2 valence electrons

 Valence electrons are those who are available to participate in bond formation.

Let’s count the valence electrons first; Magnesium belongs to the alkaline earth’s metals, having an atomic number (Z= 12) and atomic mass of 24.305 u. The electronic configuration of magnesium is Mg = [Ne] 3s2 It refers to that only two electrons are available for the bonding.

Likewise, the bromine atom belongs to the halogen family with an atomic number of 35 and an atomic mass of 79.904 u. The electronic configuration of magnesium is Br = [Ar] 4s²3d¹⁰4p⁵

 5 electrons are present for bond overlapping.

Total number of electrons in MgBr2 =  2 + 7*2 =  16

  1. Back to the mgbr2 lewis structure, now we have valence electron count = 16
  2. The arrangement of the atoms is based upon the electronegative parameter since magnesium is more electropositive and hence placed at the center and both bromine atoms at the periphery.
  3. As per the sigma bonding rule, first, we draw a single bond between the atoms and then assign the rest of the electron pairs. Now, following all the rules, we get a pictorial picture of the Mgbr2 lewis structure as shown:

MGBR2 lewis structure octet rule

It is very important for any lewis structure that it follows the octet rule as it says that every atom after participating in bond formation must have 2, 4 or 8 electrons in its outmost shell which is the indication of the stability of the structure

Let’s see whether the MgBr2 lewis structure is obeying the octet rule or not?

As it can be observed from the lewis structure of MgBr2, magnesium has a total of 4 electrons and each bromine atom has 8 electrons in its electronic arrangement after bonding. Hence, MgBr2  is obeying the octet rule.

MGBR2 lewis structure resonance

Generally, resonance structures are nothing; they just represent the delocalization of electrons from one orbit to another. However, there is one condition, i.e., there must be vacant orbitals, but in the case of MgBr2, after the bond formation, all the orbitals get fulfilled and leave no space for electrons to move.

MGBR2 lewis structure lone pairs

Let’s count how many nonbonding electrons are present on magnesium and bromine atoms. One can easily predict how many lone pairs are carried by the atom involved in the bonding.

As it is clear that the two black dots of Mg represent the valence electrons of the Mg. Now those dots that are directed towards the outside will consider lone pairs. Since Mg has no lewis dots hence it has no lone pair whereas both the bromine atoms indicate the presence of 6 lone pairs.

Hence, we got a conclusion

Lone pair on mg atom = 0

Lone pair on Br atom = 6

MGBR2 lewis structure formal charge

Calculation of formal charge for a magnesium atom

Valence electrons = 2 ( as belong to second group)

Unbonded electron count = 0

Bonded electrons = 4

F.C =  2 – 0 –  4/2 =  0

Calculation of formal charge for bromine atom

Total valence count = 7

Unbonded electron count = 6

Bonded electrons = 2

F.C = 7 -6 – 2/2 =  0

Hence total formal charge  on MgBr2 = 0

MgBr2 hybridization

MgBr2 is a typical ionic compound and before the formation of MgBr2, two electrons of the magnesium atom contributed to form MgBr2. The SP type hybridization is involved in which one orbital and one p orbital contributed during the overlapping of bonding orbitals.

MGBR2 lewis structure shape

MgBr2 possesses a linear molecular geometry according to VSEPR theory; In MgBr2, there are two Mg-Br bonds with magnesium placed between the two bromine atoms generating Br-Mg-Br-like structures with the angle of 1800.

MGBR2 lewis structure angle

 Since MgBr2 has a linear structure hence according to postulates of VSPER theory it has an angle of 1800.

MgBr2 uses

  1. Magnesium bromide is used in the synthesis of dihydropyrimidinones as a catalyst which is quite popular in the pharmaceutical world as a calcium channel blocker. In the world of chemistry, MgBr2 is known as a popular lewis acid that is used in numerous organic reactions.
  2. Apart from acting as a catalyst, Magnesium bromide, when combined with an organic group such as ethyl ( C2H5MgBr2), is used for the stereospecific analysis of triglycerols.
  3. It is direct medicinal uses such as acting as a mild sedative and also used as an anticonvulsant for the cure of various mental disorders.
  4. Magnesium bromide as magnesium bromide hexahydrate is being used as a flame retardant.
  5. The major application of MgBr2 is the synthesis of the Grignard reagent. When MgBr2 reacts with methyl in the presence of ether, the formation of CH3MgBr2 takes place, which is called the Grignard reagent.
  6. More uses can be find out at Wikipedia

Frequently asked questions:

Is mgbr2 ionic or covalent?

Covalent compounds are those which involved sharing of electrons whereas ionic compounds according to definitions are those which involve either complete loss of electrons or gain of electrons during bond formation.

By definition, it is clear that MgBr2 is ionic in nature as its formation of it, involves the removal of two electrons from the orbitals of bromine atoms.

Is mgbr2 a strong electrolyte?

 MgBr2 is a strong electrolyte because it is a good conductor of electricity also.

Why is mgbr2 a strong electrolyte?

Strong electrolytes are those which completely dissociate in the solution to give ions. Since MgBris completely dissociated in the given solution to give ions. Hence, it is considered a strong electrolyte.

How to prepare Grignard reagent from  the MgBr2?

Grignard reagents are usually prepared by the mixing of magnesium turnings with an organic halide ( CH3Cl, CH3Br) in the presence of ether. Anhydrous conditions during the whole process are required. 

  

How mgbr2 is synthesized?

Magnesium bromide can be synthesized by reacting magnesium oxide and hydrobromic acid with and crystallizing the product.

What is the solubility of mgbr2 in water?

Mgbr2 is soluble and has a solubility of around 102g/100ml.

What is the melting and boiling point of mgbr2?

Mgbr2 has a boiling point of around 1158o C and a melting point of around 7110 C

Pomila Sharma

Hello...Myself is Pomila Sharma. I have done my master's in Chemistry with a specialization in synthetic organic chemistry. I have published 4 research articles. I am very passionate about the chemistry world. I believe it's all about chemistry so let’s explore it together. LinkedIn link: https://www.linkedin.com/in/pomila008

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