13 Facts On Ibr2- Lewis Structure, Characteristics

The Ibr2- is a polyhalide that has two distinct halogens in negatively charged polyhalide ions. Let us discuss some facts about the ibr2-lewis structure in detail below.

Ibr2- is called iodine dibromide ions which consist of bromine and iodine, both are halogens that are classified in group 17 of the periodic table. These are additionally known as interhalogen compounds since they contain two halogens.

The Ibr2- which dissociates into an ion and linear fragments, photodissociates at a wavelength of roughly 400 nm. Iodine dibromide ions are used in the special titration of idometry. Let us discuss further lewis structure of ibr2 and its other facts below.

How to draw Ibr2- lewis structure?

Ibr2- lewis structure consists of iodine and bromine with a single bond in between these two halogens. Let us look at the following step to draw ibr2- lewis structure.


This phase requires us to determine the ibr2-lewis structure’s total valence electrons.

The ibr2- lewis structure has a total of 22 valence electrons in its outermost shell. Group 17 is called the halogen Group which includes both iodine and bromine. Thus, their outermost shells contain seven valence electrons each.

The compound ibr2- contains two bromine with seven valence electrons and one bromine are negatively charged and one iodine with seven valence electron.


After counting the valence electron, we have to find the least electronegative atom and place them in the centre.

In ibr2-, iodine is less electronegative than bromine. Thus iodine is placed in the centre and bromine surrounds the iodine due to being more electronegative.


Now, we have to put the valence electron in between bromine and iodine atoms. Let us discuss this below.

Ibr2- valence electrons are placed in such a manner that they follow the octet rule and occupy all the valence electrons. Iodine belongs to the 5th period in the periodic table and occupies more than 8 electrons in its shell because of its large size.


In the ibr2- ions each (:) lone pairs are converted into a single bond. Let us draw the final ibr2- lewis structure.

After assigning the valence electron for the formation of the chemical bond for the final ib2- structure, we close the whole molecule in a square bracket and assign a negative charge to it. 

ibr2- lewis structure
Ibr2- lewis structure

Ibr2- lewis structure resonance

Sets of Lewis structures known as resonance structures describe how electrons delocalize in a polyatomic ion or molecule. Let us discuss the ibr2- lewis structure resonance.

The ibr2- lewis structure does not have any resonance. Because there is no movement of electrons taking place and less electronegativity difference between bromine and iodine.

Ibr2- lewis structure shape

The Ibr2- lewis structure can be determined by the positioning of each group of electrons. Let us determine it.

The shape of the Ibr2- lewis structure is linear. Because two bromine atoms are positioned axially in the Ibr2-, which also has three lone pairs of electrons in equatorial positions to overcome the lone pair repulsions.

ibr2- lewis structure
Ibr2- lewis structure shape

Ibr2- has three lone pairs and two bond pairs with a linear structure which is enclosed in a bracket with a negative charge.

Ibr2- lewis structure formal charge

The formal charge is the theoretical charge that can be predicted by using valence electrons and other bonding and non-bonding electrons. Let us find out the formal charge of ibr2-.

The ibr2- has a formal charge of -1. That includes total valence electrons are 22 and the nonbonding electron has three pairs and bonding electrons are two pairs. Formula of formal charge is, F.C =v-l-b/2 (v= valence electron, l= lone pair, b= bonding electrons).

In the ibr2-lewis structure the formal charge on Iodine =7- 6- ½ 4= -1, Bromine= 7-6-2/2= 0. Thus Formal charge on ibr2- lewis structure = -1.

Know more about Hydrophobic Examples

Ibr2- lewis structure bond angle

The Lewis structure involved in chemical bonding is used to interpret bond angles. Let us figure out the ibr2- lewis structure bond angle.

The ibr2- has a 90° bond angle with a bent shape or geometry. In contrast, the VSEPR theory bent rule shows Ibr2- has a linear structure with a 90° bond angle.

Ibr2- lewis structure octet rule

The octet rule refers to atoms’ preference for having eight electrons in their valence shell. Let us see if ibr2- lewis structure satisfies the octet rule.

The Ibr2- satisfied the octet rule because iodine is found in the centre and bromine surrounds it. To complete the octet of the bromine atom, two bromine atoms with 14 valence electrons and then the remaining atom goes to the iodine subshell.

Bromine’s octet was completed with a total of 16 valence electrons. Because of the enlarged octet rule, the remaining valence electron undergoes in the iodine d-subshell. The total valence electron remaining is 22-16=6, which is needed to complete the iodine octet.

Ibr2- lewis structure lone pairs

Lone pairs are electrons that are found in the outermost shell of an atom. Here find out the lone pair below.

In ibr2- lewis structure a total of three lone pairs are present on the central atom of iodine. This is due to the expanded structure of iodine as it consists of 10 valence electrons. The bromine atom also has three lone pairs of electrons.

Ibr2- valence electrons

A valence electron is an electron that comes in the outermost shell of an atom, participating in a chemical reaction. Let us see how many valence electrons Ibr2- has.

The ibr2- lewis structure consists of a total of 22 valence electrons of which 7*2=14 valence electrons are from bromine and 7 from iodine.

Valence electron of Bromine=2*7=14

Valence electron of iodine =7

Negative charge= -1

Thus total valence electrons= 2Br+I+(-1) = (14+7+1)= 22.

Ibr2- hybridization

Hybridization is the process of making a new orbital by mixing two orbitals of different shapes and energy in a chemical reaction. Let us understand this.

The ibr2- lewis structure is sp3d hybridized because its steric number is five that which can be predicted by using the electronic configuration of iodine is [Kr]4d105s2p5. Thus iodine has seven valence electrons in its last shell.

Why ibr2- has sp3d hybridization?

Ibr2- is linear with sp3d hybridisation. Let us find out the reason behind it

Sp3d hybridization follows the bent rule according to which, Ibr2-lewis geometry has two bromine atoms positioned axially, which is complemented with three equatorial pairs of electrons to overcome lone pair repulsion.

Is ibr2- linear?

Linear molecules are those in which all the atoms and electron density are arranged in a straight line. Let us describe it in the case of ibr2-.

The Ibr2- is a linear structure with bent geometry and sp3d hybridization. In ibr2- all the three atoms(one iodine and two bromine) are arranged in a straight line.

Ibr2- polar or nonpolar

Polar ions are those which are oppositely charged and non-polar are those which have the same charge on their ion. Let us see if ibr2- is polar or nonpolar.

The ibr2- is a nonpolar ion, because there is an equal or symmetrical distribution of valence electron and charge to the central atom. Ibr2- lewis structure shows the symmetrical distribution of electron density on iodine and bromine.

Why ibr2- is nonpolar?

The electronegativity of the elements involved in chemical processes is correlated with polarity in the ibr2-Lewis structure. Let’s find out its non-polarity further.

The ibr2- is nonpolar due to there being no electronegativity difference between the bromine and iodine atom that attracts the electron toward their side.

Ibr2- molecular geometry

The molecular geometry will be explained with the help of the VSEPR bent rule. Let us learn about ibr2- molecular geometry.

The molecular geometry of ibr2- is linear with an angle of 90°and 120°. According to the bent rule, all lone pairs should be in an equatorial position for sp3d hybridization to reduce lone pair-lone pair repulsion.

Why does ibr2- have linear geometry?

Three lone pairs and two bond pairs make up the Ibr2- molecule linear. Let us find out the reason behind this.

A linear molecular geometry for Ibr2 due to all three of the lone pairs in Ibr2 being in an equatorial location, causes both Br to be in an axial position.

How ibr2- is linear?

The ibr2- lewis structure is linear with trigonal bipyramidal geometry. Let’s discuss this in detail.

The ibr2- is linear due to minimising the repulsion between the lone pair and bond pairs. Thus lone pair is present at equatorial and bromine at axial to form a stable structure.

Are ibr2- and xef2 isoelectronic?

Isoelectronic is a condition in which two different atoms have exactly the equal number of valence electrons in their outer shell. Let us see if ibr2- and xef2 are isoelectronic or not.

Both Ibr2- and xef2 (which is a noble gas compound) are isoelectronic as they both consists of 22 valence electrons and have a linear structure with sp3d hybridization.

Why are ibr2- and xef2 isoelectronic?

The periodic table divides the ibr2 and xef2 into two distinct groups. Let us discuss the reason being isoelectronic.

The ibr2- and xef2 are isoelectronic because both have the same bond angles of 90 degrees and consist of 22 valence electrons in their outermost shell.


The Ibr2- ion has two single bonds between each Iodine (I) atom and each Bromine (Br) atom. The Iodine atom (I) is at the centre, surrounded by two Bromine atoms (Br). Both the Iodine and Bromine atoms have three lone pairs. The formal charge of the iodine atom is -1. The ibr2- is linear in structure.

Monika Saini

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