IBr4- Lewis Structure & Characteristics (11 Helpful Facts)

IBr4is also called Iodine tetra bromide ion with the molar mass of 446.5205 g/mol. Let us discuss some facts about this molecule in detail below.

IBr4 is an inter-halogen compounds which composed of two different halogen atoms namely Iodine and Bromine. It is sparingly soluble in ether and benzene.

Let us explore the hybridization, bond angle, lone pairs, valence electrons, polarity of IBr4 in detail.

How to draw IBr4 lewis structure?

IBr4 lewis structure contains central Iodine atom which is covalently bonded to four Bromine atom and has -1 formal charge. Let us study IBr4 lewis structure in detail.

Step 1:  Find the total number of valence electrons

IBr4 lewis structure has a total 36 valence electrons. Seven valence electron from iodine, four bromine atom present in this molecule therefore each bromine atom contributes 7 valence electron and one from the negative charge.

Step 2:  Select the center atom of the molecule

Iodine is placed in the center of the molecule because of its least electronegativity. The electronegative value of iodine and bromine atom is 2.5 and 2.8 respectively. Thus central iodine is surrounded by four bromine atom.

Step 3:  Representation of chemical bond between the atoms

Electron pairs are placed between iodine and bromine atom which represents the chemical bond between the atoms.

Step 4: Remaining non-bonded electrons are added

IBr4lewis structure, bromine atom contains one electron pair. To complete the octet, place three non-bonded electron pair on the bromine atom. Iodine has more than 12 electrons is said to be expanded octet. Therefore, remaining 4 electrons is to be kept on the central iodine.

Step 5: Calculate stability of the molecule

Stability of the molecule is calculated by the formal charge of the each atom. There is negative charge on the central iodine atom and there is no charge on the bromine atom.

IBr4- lewis structure
IBr4lewis structure

IBr4lewis structure shape

The shape of the molecule is predicted by VSEPR model, electron which are present in both bond pair and lone pair repel and stay apart from each other.

The shape of the IBr4lewis structure is square planar. Four bonding electrons pairs are on the one plane and two lone pair of electrons are arranged in the opposite sides of the central iodine atom makes square planar shape. From VSEPR theory, this molecule has AX4E2 generic formula.

Square planar shape of IBr4- lewis structure
Square planar shape of IBr4lewis structure

IBr4lewis structure formal charge

Formal charge is the difference between number of valence electron in the neutral atom and outermost electron around the atom in the molecule.

The formal charge of IBr4 lewis structure is -1. The formula is given as F=V-{[L+B/2]} where V is the valence electron, L is the lone pair and B is the bonding pair of electron.

The Formal charge of

  • Iodine = 7-{4+1/2(8)}= -1
  • Bromine =7-{6+1/2(2)}=0

There is negative charge on the Iodine atoms present in the IBr4 lewis structure. Therefore, overall formal charge of this molecule is -1.

IBr4lewis structure angle

The geometric angle which is formed between two adjacent covalent bond is termed as bond angle.

IBr4molecule has the bond angle of 90˚. It is not affected by the symmetrically arranged central atom lone pair electrons, which do not compress I-Br bond angles.

IBr4lewis structure octet rule

Octet rule states that the atom prefers to have eight electrons in its outermost shell. Let us discuss octet rule for IBr4lewis structure.

Bromine atom present in the IBr4lewis structure obeys octet rule. Six non-bonded electrons and two bonded electrons present on the bromine atom makes octet. Iodine is present in period 3 element often exhibits expanded octet of 12 electrons.

IBr4lewis structure lone pairs

Lone pair electrons are unshared electron which are not take part in the formation of the chemical bond. Let us explore lone pair electron of IBr4molecule.

Total 14 lone pair electrons are present in Lewis structure of IBr4. Each bromine atom present in this molecule has 3 lone pair of electrons therefore, 4 bromine atom have 12 lone pair of electrons. 2 lone pair of electrons is present in central iodine atom.

IBr4 valence electrons

Valence electrons present in the outermost shell which have high energy compared to the core electrons. We will discuss same for IBr4 molecule.

IBr4 molecule consists of total 36 valence electrons. Iodine and bromine atoms are present in the halogen family with 7 valence electron. Since four bromine atom present in IBr4 molecule and it has -1 formal charge. Therefore total valence electron of this molecule is 7+7(4)+1=36.


Hybridization occurs due to the mixing of two atomic orbital having equal energy to form a new hybrid orbital. We will study IBr4hybridization in detail.

IBr4 molecule has sp3d2 hybridization. In this molecule one electron of central iodine atom, each from 5s and 5p orbitals is promoted to 5d orbitals hybridized to form 6 sp3d2 hybrid orbital of same energy. Each sp3d2 hybrid orbitals overlap with 4p orbitals of bromine to form I-Br bond.

Is IBr4polar or nonpolar?

The electrons are not evenly distributed and have asymmetrical shape in polar molecule whereas, electrons are evenly shared between the atoms in case of nonpolar molecule.

The nature of IBr4is nonpolar. The difference in electronegativity of Br and I is 0.3 which is a nonpolar. They have symmetrical shape, dipoles of four Br bonded to central I atom cancel each other. The dipoles of two lone pairs on I atom cancel each other resulting in a no net dipole in it.

Is IBr4electrolyte?

An electrolyte contains ions which is responsible for the electrical conductivity in aqueous solution.

IBr4 is not an electrolyte. It is not an ionic compound which produces ions in an aqueous solution. The absence of the ions in the aqueous solution makes IBr4which do not conduct electricity therefore it does not acts as electrolytes.

Is IBr4ionic or covalent?

The electronegativity difference between the bonded atoms is more than two leads to the formation of ionic bond. If its value is less than two, then the bond is covalent bond.

IBr4is covalent in nature. The difference in the electronegativity of I and Br atom is 0.3 which is said to be formation of covalent bond. There is sharing of electrons takes place in IBr4 molecule which is considered as covalent compound.

Is IBr4soluble in water?

The compound which is polar and presence of hydrogen bond will soluble in polar solvent such as water.

IBr4is insoluble in water. This molecule is non polar in nature and there is no hydrogen bond. Hence there is no interaction between the water molecule and IBr4 molecule.


IBr4 possesses square planar shape with sp3d2 hybridization. The bond angle of this molecule is 90˚. It is non polar in nature and is covalent compound. It do not forms hydrogen bond.

Supriya Upadhya

Hi....I am Supriya Upadhya, a 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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