BrO2- lewis structure, Characteristics:13 Facts You Should Know


This article contains the BrO2- lewis structure, mode of hybridization, bond angle, and many more detailed facts.

In the BrO2- lewis structure molecule is bent shaped but due to the presence of two pairs of lone pair geometry is tetrahedral. The central Br atom sp3 hybridized with bond angle 1090 with no deviation from the ideal bond length. Two Oxygen atoms bind with Br via a double bond single bond.

Bromite is an oxoanion of Br. The Br-O bond length is around 178 pm for a single bond and 153 pm for a double bond and the molecule is asymmetric so it has some dipole moment and it is a polar molecule.

1.    How to draw BrO2- lewis structure?

Lewis structure or lewis dot structure helps us to find the number of electrons involved in the bond formation or the number of lone pairs available in a molecule.

BrO2- lewis structure
BrO2- Lewis Stucture

In BrO3- lewis structure, the total electrons involved is 7+ (6*2)+1 = 20, where 1 is for negative charge and the electrons needed 8+(8*2)= 24, So the bonding electrons will be 24- 20= 4 electrons and the number of the total bond will be 4/2 =2 bonds. So, in the BrO2- there will be at least two sigma bonds present.

To draw the BrO2- lewis structure we need to calculate the total valence electrons of individual atoms that is Br and O and they are added together. Now we have to find the central atom based on its less electronegativity. Compare between Bromine and O, Br is less electronegative than O so, Br is the central atom here.

Now Bromine and O are connected via covalent bonds. Two Oxygen are getting connected with Br via a single bond and one oxygen is attached via a double bond to complete the octet.

Lone pairs are assigned to the central Br and the negative charge is on one of the Oxygen atoms which is connected through a single bond only.

2.    BrO2- lewis structure shape

In the BrO2- lewis structure the electron density lies around the central Br atom only.

From the BrO2- lewis structure it is evident that the molecule is bent shape like a water molecule with two lone pairs present over the Br atoms only. Considering the lone pair, it will adopt tetrahedral geometry as is evident from its bond angle data.

Unlike water here one double bond is present and due to the more electronegative atom is present so the bond angle is near about 1090 in its tetrahedral geometry.

3.    BrO2- valence electrons

In the BrO2- lewis structure Br and O contain valence electrons in their valence shell.

BrO2- Valence Electrons

In the BrO2- lewis structure the central Br are connected with two O atoms via a single bond and a double bond respectively. There are two lone pairs are present over the Br atom and a negative charge is present in the oxygen atom which connected through a single bond only.

From the electronic configuration of Bromine and O, we know that there are seven and six electrons present in their valence shell of them respectively. Among seven electrons Br used 3 electrons for bond formation and four electrons exist as two pairs of lone pairs.

One oxygen gets seven electrons in its valence shell due to a negative charge over it.

In the BrO2- lewis structure total valence electrons are = 7+7+6=20 electrons.

4.    BrO2- lewis structure formal charge

Considering the same electronegativity for all atoms in a molecule to find the charge accumulated by them is called a formal charge.

The formula we can use to calculate the formal charge, F.C. = Nv – Nl.p. -1/2 Nb.p.

In the BrO2- lewis structure there are two types of Oxygen atoms present one is bearing a negative charge and one is forming a double bond so their formal charge will be different.

Formal charge accumulated by Br = 7-4-(6/2) = 0

The formal charge accumulated by O containing double bond = 6-4-(4-2) = 0

The formal charge accumulated by O bearing negative charge  = 6-6-(2/2) = -1

Bromite anion is also containing a negative charge and it is also derived from its formal charge also. The formal; charge also satisfies the number of ionic species.

5.    BrO2- lewis structure lone pairs

Electrons present in the valence shell or outermost orbitals of an atom in a molecule but not involving direct bond formation are called lone pairs.

BrO2- Lone Pairs

From the BrO2- lewis structure Br and O both are P block elements and they are from group VIIA and VIA respectively. That means Br has seven and O has six electrons in their valence shell.

Out of seven electrons of Br in BrO2- lewis structure three electrons participate in bond formation and the rest of the two electrons are present as two pairs of lone pairs.

For O which formed a double bond with Br having four electrons left in its valence shell which exists as lone pairs and for that o which contains negative charge has six electrons in its valence shell and they present as three pairs of lone pairs.

So, the total number of lone pairs available in BrO2- lewis structure which is not involved in bond formation is, 2+2+3 =7 pairs of lone pairs which means 14 electrons.

6.    BrO2- lewis structure octet rule

Every atom in bromite tries to complete its valence shell by accepting or donating a suitable number of electrons and adopting the nearest noble gas configuration in accordance to octet rule.

BrO2- Octet

From the BrO2- lewis structure it is evident that out of seven electrons of Br in its valence shell it formed 3 bond pairs and there will be two lone pairs present on it.

Br is a group VIIA element so it has seven electrons in its valence shell where four electrons are present as lone pairs and Br shares two electrons with two O atoms to form two sigma bonds which mean four electrons are involved in the bond pair.

O is a group VIA element so it has six electrons in its valence shell and out of six electrons four electrons are present as lone pairs and the rest of the four electrons are involved in bond formation with Br via sharing electrons with Br. This way O complete its octet.

Now one Oxygen atom which forms only a single bond with Bromine has six electrons as lone pairs and shares two electrons with Br to form a sigma bond and complete its octet too via adopting a negative charge.

7.    BrO2- lewis structure bond angle

In the Bromite structure, Br and two O form a particular bond angle in the perfect arrangement of the molecule to stabilize the molecule.

BrO2- Bond Angle

From the BrO2- lewis structure molecular shape is bent. From the VSEPR (Valence Shell Electrons Pair Repulsion) theory, we can be told that the bent-shaped molecule has a bond angle lower than 1200.

The geometry of the molecule is tetrahedral due to the presence of two lone pairs over the Br atom. So, the bond angle is expected to be 109.50 and the Br-O-Br bond angle in bromite is 1090 which is the almost ideal bond angle for tetrahedral geometry.

This data govern that there is no reason for deviation of bond angle from its ideal value because Br is large and there will be only two O atoms present so the chance of lone pair repulsion is minimized here but due to some electronegativity, there is some sort of bond angle.

8.    BrO2- lewis structure resonance

In BrO2- lewis structure it can adopt many skeleton structures where the electronic clouds of the molecule can be delocalized, the process is called resonance.

BrO2- Resonating Structure

In BrO2- lewis structure it is possible to adopt all the above structures.

Structures I and II are similar and they are the highest contributor to the resonance of Bro2- lewis structure because they have a higher number of covalent bonds and electronegative atom O gets a negative charge.

Structure III is less contributor as it carries a lower number of the covalent bond and electronegative atom Br gets a positive charge which is a destabilization factor.

9.    BrO2- hybridization

In BrO3- lewis structure the molecule is sp3 hybridized where two orbitals of Br and O atoms of different energy undergo mixing to give a new hybrid orbital of equivalent energy.

For bromite ions, hybridization is calculated by the formula,

H = 0.5(V+M-C+A), where H= hybridization value, V is the number of valence electrons in the central atom, M = monovalent atoms surrounded, C=no. of cation, A=no. of the anion.

In BrO3- lewis structure, Br has four electrons as lone pairs and two electrons are involved for two sigma bond formation with two O atoms.

So, the central atom Br is, ½(6+2+0+0)= 4 (sp3 hybridized)

Structure  Hybridization value State of hybridization of central atom  Bond angle
Linear       2sp /sd / pd    1800
Planner trigonal 3  sp2     1200
Tetrahedral    4sd3/ sp3    109.50
Trigonal bipyramidal 5sp3d/dsp3    900 (axial), 1200(equatorial)
Octahedral6sp3d2/ d2sp3       900
Pentagonal bipyramidal7sp3d3/d3sp3    900,720

                    If the hybridization value is 4 then we can told that the central atom should be sp3 hybridized.

BrO2- Hybridization

From the box diagram of BrO2- lewis structure it is evident that we consider only sigma bonding in hybridization, not the π bond.

Br has five electrons in its 4p orbital in the ground state, In the excited state, it transferred one electron to its 4d orbital and for two sigma bonds with two unpaired electrons present in the 4p orbital. So, for Br, there are two lone pairs one in 4s and the other in 4p orbital, and two bond pairs in 4p orbitals are involved in hybridization.

So here one 4s and three 4p orbitals are undergoing mixing to give an sp3 hybrid orbital.

Again, from hybridization, we can say that if the molecule is sp3 hybridized then the central atom makes 109.50 with other substituents and the bond angle of BrO2- is around 1090 which is match its hybridization value also.

 So, we can say that hybridization and VSEPR theory can predict the same result for the bond angle of a molecule, where one can predict the bond angle from the structure and one can from its hybridization value.

10.    BrO2- solubility

The solubility of bromite ion depends on the temperature and particular solution.

In the BrO2- lewis structure there is one negative charge present to make the molecule more anionic and for this reason, it can ionizable in water and gets soluble in it. The lone pair also help to be soluble in the solution to coordinate with the solution.

11.      Is BrO2- ionic?

From the BrO2- lewis structure we can say that it has some ionic character along with the covalent character. According to Fajan’s rule, all the covalent molecules have some ionic character and it depends on their ionic potential and polarizability. Br has less tendency to polarize small anions like oxygen so it has lower polarizability and lower value of ionic character.

Also, Br has higher ionic potential for its electronegativity so the molecule possesses some ionic character, and also the molecule is charged so it has ionic nature in it.

12.    Is BrO2- acidic or basic?

It is a conjugate base of Bromous acid so generally, it is basic. The counter ion H+ can be attached to the BrO2- lewis structure which gives the Bromous acid.

So, we can say that on ionized Bromous acid we get bromite as the counter anion, and it is a conjugate base of the respective acid. As Bromous acid is a weaker acid so its conjugate base bromite is stronger.

13.    Is BrO2- polar or nonpolar?

Due to the bent shape of the bromite ion, it is a polar molecule.

BrO2- Dipole Moment

From the BrO2- lewis structure it is evident that the molecule is a bent shape and the dipole moment acts from Br to O (as the dipole moment acts from more electronegative substituents to less electronegative substituents). There will be some resultant dipole moment shown in the BrO2- lewis structure so the molecule is polar.

Conclusion

From the above discussion of BrO2- lewis structure we can conclude that it is bent shape but with the presence of lone pair, it adopts tetrahedral geometry with bond angle 1090. There is no deviation factor is present for bond angle. Due to its bent shape, it has a dipole moment and makes the molecule polar. Bromite is a stronger conjugate base of a weak acid.

Biswarup Chandra Dey

Chemistry is not all about reading line by line and memorize, it is a concept to understand in easy way and here I am share with you the concept about chemistry which I learn because knowledge is worth to share it.

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