BrF2 Lewis Structure,Characteristics:13 Must To Know Facts


We will discuss about drawing Lewis structure of BrF2, resonance, shape, formal charge, angle, octet rule, lone pairs of BrF2 Lewis structure. Valence electron, hybridization, solubility, covalent nature and polarity of BrF2 is also explained.

BrF2 is also termed as Bromo difluoride. Bromine atom has got two fluorine atoms around it in BrF2 ion Lewis structure. They form covalent compound by sharing electron between the Bromine (Br) atom and each Fluorine (F) atom. The Fluorine atoms have 3 lone pairs of electrons.

How to draw BrF2 Lewis structure?

Lewis structure of BrF2 can be drawn as shown below:

Step 1:  Take the count of valence electrons

Bromine and Fluorine are the group of halogen which comes in the 17th group of periodic table and they have got 7 valence electrons each.

Number of electrons in outermost valence shell of Bromine atom in BrF2 = 7

Number of electrons in outermost valence shell of Fluorine atom in BaF2 = 7

Bromo difluoride has got two fluorine atom making total valence electrons availability as 7+7(2) = 21.

Valence electron of Bromine and Fluorine from Shutterstock

Step 2: Choose least electronegative atom and insert in the center of the molecule.

The value of electronegativity decreases from top to bottom down the group in the periodic table. Hence, electronegative value of bromine is less compared to the electronegative value of fluorine.

Due to its least electronegativity, Bromine atom is kept in the center of the molecule and is surrounded by two fluorine atoms.

Bromine is kept in center is surrounded by two fluorine atom
Bromine is kept in center is surrounded by two fluorine atom

Step 3: To represent a bond between the atoms put two electrons

Put two electrons between each bromine atom and fluorine atom such that bonds are formed between each atoms in a BrF2 molecule.

Two electron are placed between each Bromine and Fluorine atom
Two electron are placed between each Bromine and Fluorine atom

Step 4: To complete the octet, the remaining non-bonded electrons are distributed among the atoms.

There are total 21 valence electrons are present in the BrF2 molecule. Out of these, four electrons are used to make bond with the bromine-fluorine atoms and remaining 17 electrons are non-bonded electrons.

Each fluorine atom takes six electrons each from non-bonded electrons and two electron from single bond formed with bromine to complete the octet. Since there is two Fluorine atoms present in the BrF2 molecule, it takes 12 non-bonded electrons.

The remaining 5 non-bonded electrons left to be kept on the central atom that is Bromine atom and also four electrons are used to form the single bond with the fluorine atoms. Therefore bromine acquires a total nine electrons and forms an expanded octet.

BrF2 Lewis structure resonance:

It is not possible to write the resonance structure for the Bromo fluoride Lewis structure because due to complete octet configuration of Fluorine and expanded octet configuration of Bromine.

In BrF2, electrons surrounding the bromine central atom must be expanded beyond an octet that is nine electrons in its valence shell. Bromine exceed the octet rule by using their empty 4d orbitals to accommodate additional electrons. Therefore it will not form a bond using its own lone pair electron.

Octet for two fluorine atom is complete and it cannot accommodate extra electrons.

BrF2 Lewis structure shape:

BrF2 Lewis structure do not have any shape because the central bromine atom is surrounded by 4.5 regions of electron density – two single bonds and 2.5 lone pairs, which means that its steric number will be equal to 4.5 which is a decimal digit.

The 5 non-bonded electrons of the central bromine atom shows high repulsion in between them and also these non-bonded electron are odd in nature therefore shape of bromo difluoride do not show any shape.

BrF2 Lewis structure formal charge:

The charge which is assigned to bromine and fluorine atoms to have two atoms in a molecule equally sharing electrons  between them.

Formal charge of the BrF2 Lewis structure is nothing but

Formal charge= [Free state valence electrons count]-{[total lone pair electrons count] + 1/2[total bonding electrons count]}

For Bromine we see it as below:

Number of valence electrons in Bromine =7

Total number of lone pair electrons = 5

Total number of bonding electrons = 4

Formal charge of Bromine= 7-{5+1/2(4)}

                                        = 0

Formula charge on bromine atom in Bromo fluoride Lewis structure is 0

For fluorine:

Number of valence electrons in fluorine =7

Total number of lone pair electrons in fluorine=6

Total number of bonding electrons = 2

Formal Charge of fluorine=7-{6+1/2(2)}

                                      =0

The fluorine atom in BrF2 Lewis structure has a formal charge of 0.

BrF2 Lewis structure angle:

BrF2 Lewis structure do not have any angle. Since they do not have particular shape due to the presence of odd number of non-bonded electron therefore it is not possible to predict the angle.

BrF2 Lewis structure octet rule:

In BrF2 Lewis structure, Fluorine atom has total eight electron in its outermost shell therefore it has complete octet configuration. Bromine atom deviate from the octet rule by having more than eight electron in its outermost shell. Therefore bromine atom has expanded octet.

BrF2 Lewis structure lone pair:

Lone pair electrons are those electrons which does not involve in bonding process.

Lone pair electron of Bromine in Bromo fluoride Lewis structure = 2 paired electron and one unpaired electron.

Lone pair electron of fluorine in Bromo fluoride Lewis structure = 3

BrF2 valence electron:

Electronic configuration of bromine is [Ar] 4s2 3d10 4p5

Number of outermost electrons which are present in Bromine is seven. Hence it is seen that the outermost electrons are present in 4s and 4p orbital.

Electronic configuration of fluorine is 1s22s22p5

Outermost electron present in the fluorine is 7

Two fluorine atoms present in the Bromo difluoride therefore, the total number of valence electrons of BaF2 is 7+7(2) =21.

BrF2 hybridization:

The electronic configuration of Bromine atom in the valence shell is 4s2 4p5. In the ground state of Br atom we see that there are only one unpaired electron and to form BrF2, 2 unpaired electrons are needed. In the excited state one electron from 4p orbital of the Bromine atom is excited to 4d orbital making a total 3 unpaired electrons.

Pairing happens for two fluorine atoms with help of two electrons by leaving one unpaired electron. The unpaired electron present in the 4d orbital is highly unstable and it is not exist.

Three possible ways of BrF2 become stable molecule

  1. By losing one electron it forms sp3 hybridization with two lone pair of electron.
  2.  BrF2 can bond with another fluorine atom to form BrF3 molecule which attain sp3d hybridization
  3. By gaining one electron BrF2 can form BrF2 which attain sp3d hybridization

BrF2 Solubility:

Hydration energy of the BrF2 is low therefore solubility is also decreases. BrF2 is interhalogen compound, on hydrolysis they convert into fluoro ion and Bromo oxyfluoride ions.

How BrF2 is less soluble in water?

Hydrolysis of interhalogen compounds produces a halide ion derived from smaller halogen that is from fluorine and oxyfluoride ion from the larger halogen that is from the Bromine.

Why BrF2 is less Soluble in water?

As we move down the group, the size of the atom increases due to the addition of extra valence shell. Greater the size of the bromine ion, lower will be the hydration energy this is because larger atom cannot accommodate a large number of water molecules around.

Is BrF2 ionic?

BrF2 is not ionic compound but it is covalent in nature.

Why BrF2 is not ionic?

In ionic compounds complete transfer of electron takes place and metal atom donate the electron and this electron is accepted by the non-metal atom in ionic compound.

But in BrF2, complete transfer of electron is not takes place instead of, sharing of electron is found in this molecule therefore BrF2 is a covalent compound and also it is inter-halogen compound therefore ionic bond is not present.

How BrF2 is not ionic?

BrF2 is covalent in nature because electronegativity value of Bromine is 2.96 and electronegativity value of fluorine is 3.98, the difference between electronegativity of Bromine and Fluorine in BrF2 molecule is 1.02 lesser than 1.5 which comes under covalent character.

Is BrF2 acidic or basic?

It will hard to determine the acidic and basic nature of BrF2 molecule.

Why it is hard to determine the acidic or basic character of BrF2?

Bromine atom has 2 lone pair of electrons and one unpaired electron.  Hence it is hard to determine acidic or basic nature of the molecule.

How it is hard to determine the acidic or basic character of BrF2?

Lewis acid are electron pair acceptor. If BrF2 accepts one electron then it forms BrF3which is a Lewis acid whereas, if it loses one electron it acts as a Lewis base.

Is BrF2 polar or nonpolar?

It is hard to determine the polar and nonpolar nature of BrF2.

Why it is hard to determine the polarity of BrF2?

Polarity of the molecule depends upon its shape and polarity of the bond. For polar covalent molecule the value of the electronegative has to vary from 0.5 to 2.0.

How it is hard to determine the polarity of BrF2?

BrF2 molecule does not have any shape and the electronegative value of Bromo difluoride is 1.02. Therefore it is hard to determine the polar and nonpolar nature of BrF2.

Summary:

In this article we studied the how to draw the Lewis structure for Bromo difluoride, resonance structure, valence electron, lone pair of electron. sp3dhybridization, polarity of the molecule, solubility property and acidic property is also studied.   

Supriya Upadhya

I am Post Graduate in Organic chemistry with good understanding of Chemistry concepts and worked as Junior research fellow in synthesis of anti cancer agent. Also worked on Anti-Microbial Polymer synthesis as part of Post graduate thesis. Linkedin profile: https://www.linkedin.com/in/supriya-upadhya-1223a716a/

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