IO3- lewis structure: Drawings, Hybridization, Shape, Charges, Pairs

In this article we are discussing about io3- lewis structure including its drawing, hybridization, shape, pairs and some FAQS.

Iodate is an oxoanion of iodine. It is formed when Iodic acid losses one proton. It has the molecular weight of 174.903. Usually iodates occur in nature as salts which are generally colorless.

IO3- Lewis Structure Drawing

As iodine is bigger in size and has less electronegativity than O atom I act as the central atom in this compound.

Iodine has 7 valance electrons out of which 3 electrons take part in sigma bonding with 3 O atoms and forms 2 pi bond with 2 O atoms. One electron pair still present on I atom which remains as lone electron pair on central I atom. O atom has 6 valance electrons out of which 1 is used in making sigma bond and 1 is used in making pi bond and remaining 4 electrons present as lone pair of electrons on O atom.

IO3- Lewis Structure Resonance

Resonance means movement of electrons from one atom to another atom and the structure obtained by this process is called canonical structure.

Io3- has 3 canonical structures. In all the structures I-O bond has partial double bond character due to delocalization of electron pair that present on O atom with empty antibonding orbital of I=O double bond.


IO3- Lewis Structure Shape

According to VSEPR theory the shape of io3- is pyramidal in which iodine is tetrahedrally surround by 2 O atoms and 1 O- ion. Due to the presence of 1 lone pair on central I atom ideal tetrahedral geometry does not occur. As lone pair is absent on I atom the geometry of this compound is tetrahedral. But as because lone pair is present the structure becomes is distorted and the correct geometry is pyramidal.

IO3- Lewis Structure Formal Charge

The formal charge on any atom or ion can be calculated by the formula given below:

Formal Charge (f) =V-B/2-N


V= No of valance electrons, B= No of bonding electrons, N= No of nonbonding electrons.

Hence formal charge on I atom in io3- = 7-10/2-2=0.

Formal charge on each double bonded O atom in io3- =6-4/2-4=0.

Formal charge on single bond O atom in io3- =6-2/2-6=-1.

Hence iodine atom has 0 formal charge on it. Each double bond O atom has 0 and single bond O atom has -1 formal charge making the whole compound is negatively charged.

IO3- Lewis Structure Angle

Io3- has distorted tetrahedral geometry hence normal tetrahedral bond angle 109028 does not arises here. This is because of lone pair present on I atom.

In this compound both lp-lp and bp-bp repulsion occurs. But lp-lp repulsion is stronger in nature than bond pair-bond pair electronic repulsion. To minimize this bond pair-lone pair repulsion O-I-O bond angle is reduced to 1000 from 109028’.

IO3- Lewis structure Octet Rule

In the lewis structure of io3- we found that each O atom has 8 electrons in its outermost shell and fulfill their octet. In io3- ion I forms 2 I=O double bonds and 1 I-O single bond, also there exist 1 lone pair of electron that present on central I atom creating a total of 12 electrons around I atom. As I is a member of 3rd period element. It can increase their octet more than 8 electrons. Hence according to octet rule iodate is a stable compound.

IO3- Lewis Structure Lone Pair

The valance shell electron that don’t take part in sigma as well as pi bonding is called lone pair of electron or nonbonding electrons pair.

The basic formula with the help of which we can find the lone pair of electron on the given atom is given below:

No of lone pairs= Total no of valance electron of the atom-no of bonds formed by that atom.

In io3- lone pair present on I atom= 7-5=2 i.e. 1 lone pair

Lone pair present on each double bonded O atom=6-2=4 i.e. 2 lone pair.

Lone pair present on single bonded O- ion= 8-2=6 i.e.3 lone pair.

These lone pair of electrons is found In the lewis structure of io3- on the given atoms as electron dots.

IO3- Valance Electrons

Firstly to find out the total valance electron in io3- ion, it is important  to know the electronic configuration of I and O atom.

The electronic configuration of I is [Kr36]4d105s25p5 and as we see from electronic configuration that there are 7 electrons in valance shell of I atom. The electronic configuration of O atom is [He2]2s22p4. There is 6 electrons in the valance shell of O atom. Also one negative charge is present on O atom.

The total valance electrons that present on io3- ion will be equal to the (sum of the valance electron of I and O atom+1 negative charge) i.e. equals to (7*1)+(6*3)+1=26. There are 26 valance electrons in io3- ion.

IO3- Lewis Structure Hybridization

Hybridization is the process in which hybrid orbitals are formed by mixing of same energy atomic orbitals.

The ground state outermost shell electronic configuration of I is 5s25p5. As we see from electronic configuration of I atom that there is only 1 unpaired electron and to form io3- ion 3 unpaired electron is required. In the excited state, I transfer 2 p electrons in 5d orbital and now a total of 5 unpaired electron is present.

In the next step 3 O atom gave 3 unpaired electron to form 3 electron pair by which 3 I-O single bond is formed. There still 1 unpaired electron present on O atom which forms 2 I=O pi bonds.

In this compound I uses sp3 hybrid orbital to make I-O bonds. Due to sp3 hybridization iodate should have tetrahedral geometry but as because of presence of lone pair of electron the shape of io3- ion is pyramidal.

Io3- Uses

Iodates are used in treatment of thyroid gland disorder.

It used in iodometry for the manufacture of medicine.

It is used in the analysis for testing arsenic and zinc salts.

Sometimes it is used for iodination of table salt to remove iodine deficiency.

Some FAQS About IO3-

Is IO3- Ionic or Covalent?

Io3- is a covalent compound. Iodate is formed by covalent sigma bond formation. When a ionic compound is formed, one or more electron is moved towards electronegative atom from less electronegative atom. Here in the formation of this compound nothing happens. Io3- ion is formed by sharing of electron pair between I and O atom. Hence it is a covalent compound.

Is IO3- Stable?

Io3- is a stable compound. As lone pair of electron is present on I atom lp-bp repulsion is occurred. For this reason its stability is decreased. But due to resonance each I-O bond gets a partial double bond character which overcomes lone pair-bond pair repulsion and makes the compound stable.

Is io3- polar in nature?

Io3- is polar in nature. A molecule is found to be polar if its dipole moment(µ) is not equal to 0. In this compound 3 I-O bonds are polar this is due to electronegativity difference between I and O atom. As I is more electronegative than O atom the 3 I-O bond moments lies towards I atom.

Susanta Maity

Hi....I am Susanta Maity. I have completed my Masters from Vidyasagar university with a specialization in organic chemistry. I love to write complicated Chemistry concepts in understandable and simple words. Let's connect through LinkedIn:

Recent Posts