HClO3 Lewis Structure, Characteristics: 33 Complete Quick Facts

In this article, we should discuss the HClO3 lewis structure and different characteristics facts. Let’s start the article with the covalent character of the HClO3 lewis structure.

In the HClO3 lewis structure, Cl is in a +5 oxidation state and it is its highest oxidation state so, it can behave oxidizing agent, can undergo reduction, and oxidized other substituents. The pka value of HClO3 is very low almost negative, so it is a strong inorganic acid. the central Cl atom is sp3 hybridized here. The geometry around the central Cl is pyramidal in the HClO3 lewis structure.

There are two double-bonded O atoms and one -OH group is attached to the central Cl atom. The central Cl contains five bond pairs and one lone pair. The geometry around a single O is bent-shaped.

Some important facts about HClO3

HClO3 is liquid in a physical state. It is a colorless liquid compound. The molar mass of Chloric acid is 84.45 g/mol. The density of the acid is 1g/mL.

The chloric acid may be prepared by the reaction of sulfuric acid with barium chlorate in the laboratory. The insoluble barium sulfate is removed by the precipitation method.

Ba(ClO3)2 + H2SO4 → 2 HClO3 + BaSO4

Heating the hypochlorous acid is another method to prepare the chloric acid along with hydrochloric acid.

3 HClO → HClO3 + 2 HCl

The aqueous solution may be concentrated up to 40% in Vaccum; decomposition occurs on further concentration or warming:

8 HClO3 → 4 HClO4 + 2 H2O + 2 Cl2 + 3 O2

3 HClO3 → HClO4 + H2O + 2 ClO2

Chloric acid and its conjugate base chlorate both are strong oxidizing agents.

3KClO3 + 4HCl = 2KCl + Cl2 + 2ClO2 + 2H2O

The mixture of Cl2 and ClO2 is known as euchlorine.

1.    How to draw the HClO3 lewis structure?

To draw the HClO3 lewis structure, we have to follow the octet rule as central Cl is from the p block element. With the help of the lewis structure, we can understand the different covalent properties of HClO3.

HClO3 lewis structure
HClO3 Lewis Structure

Step 1-  In the first step of the HClO3 lewis structure, we should the count valence electrons of every substituent individually and add them together. Now coming with Cl, which is p block, group 17th element. So, it has seven electrons in its valence orbital.

Now for O, it is also the p block element and group 16th element. It belongs to the group VIA element so it has six electrons in its valence orbital, one electron less from Cl. There are three O atoms present so total valence electrons are 3*6 = 18 electrons.

Now come for the last atom which is H. H is the group IA element and it has only one electron which is its valence electron only.

So, in the HClO3 lewis structure, total number of valence electrons are 7+18+1 = 26 electrons.

Step 2- in the 2nd step of lewis structure drawing, we decide which will be the central atom. Here ambiguity occurs between O and Cl atoms. Both are p block elements and the electronegativity is almost the same for those two elements. But they differ in their size. 

The size of Cl is larger than O, because down the group of periodic table size increases due to an increase in the principal quantum number of atoms.

So, Cl is chosen as the central atom here and three O atoms are present as three surrounding atoms.

Step 3-  All the atoms in the HClO3 lewis structure are from s and p block elements. So, the octet rule is applied here. According to the octet rule s block element complete its outermost orbital by a maximum of two electrons.

By the octet rule of the p block element, they complete their valence shell by eight electrons as the p orbital contains a maximum of six electrons, and the p block element always contains s orbital and there are two electrons.

So according to the octet rule, the required electrons for the HClO3 lewis structure are 4*8 +2 = 34 electrons. But the available valence electrons in the HClO3 lewis structure are 26 electrons. So, the shortage of electrons is 34-26 = 8 electrons. Those 8 electrons are accumulated in the 8/2 = 4 bonds among the substituents in the HClO3 lewis structure.

Step 4- Now in this step, we joined all the atoms with each other in the HClO3 lewis structure by the required number of bonds. Cl is the central atom here so Cl is presented as the central position and then adds the required number of bonds to connect all the atoms. Three O atoms are connected with three single bonds with the central Cl atom and one bond is used for connecting one H with one of the O atoms.

So, all the four bonds are used properly and used for only sigma bond formation only.

Step 5- In the last step, we should check whether all the atoms in a molecule are satisfied by their octet or not. To satisfy their octet we should add multiple bonds and assign lone pairs over them. To complete the octet of central Cl, we should add two double bonds between Cl and two atoms. Now one lone pair is assigned over the Cl atom.

All the three O atoms make two bonds whether a double bond with central Cl or one bond with central Cl and one bond with the H atom. Now four lone pairs are assigned over them.

2.    HClO3 lewis structure shape

The geometry of the HClO3 lewis structure is almost the same around central Cl and O atoms, but the shapes are different due to the different environments present. As Cl is the central atom so we focus the shape around the central Cl atom in the HClO3 lewis structure. The shape is pyramidal.

HClO3 Shape

The geometry of a molecule is decided by the VSEPR (Valence Shell Electrons Pair Repulsion) theory or the presence of surrounding electrons. Now from the VSEPR theory, we can say that if the AX3 type of molecule having lone pair over the central atom is always adopted tetrahedral geometry.

Tetrahedral geometry is ideal for an 8 electrons system, but due to lone pair-bond repulsion, there will be deviated from the actual shape.

In the HClO3 lewis structure, there are two double bonds present, we know double bonds required more space and there are also lone pairs present. Due to avoid repulsion it adopts a pyramidal shape around the central Cl atom.

 But here another shape is present in this molecule. The geometry around single-bonded O atoms is different from the central Cl atom. In the single-bonded O atom, there will be an electron count will be 8 and it is expected that it should adopt tetrahedral geometry. But it adopts a bent shape like a water molecule due to repulsion in the surrounding environment.

3.    HClO3 valence electrons

In the HClO3 lewis structure, the valence electrons are contributed from its substituents like Cl, O, and H atoms. Individually predict the valence electrons for every atom and add them together to get the total valence electrons for the HClO3 lewis structure.

There Cl, O, and H atoms are present as substituents in the HClO3 lewis structure.

The group 17th element Cl has an electronic configuration [Ne]3s23p5. It is present as a VIIA element in the halogen family. From the electronic configuration of this element, we can say that the valence orbital of Cl is 3s and 3p. There is a total of seven electrons present in the respective orbital. Those seven electrons are valence electrons as they present at the valence orbital, those electrons participate in the bond formation or donation.

Now the electronic configuration of group 16th element O is [He]2s22p4. It is present at the VIA element and from the electronic configuration, we can say that 2s and 2p orbitals are the valence orbital or outermost orbital for O. so the electrons present in those orbitals are the valence electrons for O. So, O has six valence electrons as two electrons are present in the 2s orbital and 4 electrons are present in the 2p orbital.

Now come for H. it is the first element in the periodic table and the position of its 1st group and 1st period.. It belongs to group IA and its electronic configuration is 1s1. So, the 1s orbital is its valence orbital and only one electron is the valence electron for H.

So, the total valence electrons for HClO3 lewis structure are, 7+(6*3)+1 =26 electrons.

4.    HClO3 lewis structure lone pairs

In the HClO3 lewis structure, only Cl and O atoms contain the lone pair only. The total lone pairs of the HClO3 lewis structure is the summation of the lone pairs of individual atoms.

To count the lone pair for every individual atom we should check the electronic configuration and valence electrons for individuals. Lone pairs are the one kind of valence electrons because they are present in the valence shell of every atom but do not participate in the bond formation and exist as pair of electrons over the respective atom. It contributes to the octet rule.

From the electronic configuration of Cl, it is evident that there are seven electrons present for Cl as valence electrons, now Cl formed three sigma bonds with three O atoms and two double bonds with two O atoms. So, after the multiple bond formation, two electrons are remaining in the valence shell for Cl. Those two electrons exist as lone pair for Cl.

For three O atoms, two O atoms are making a double bond with Cl and one O atom makes one bond with Cl and one bond with H. so three O used their two electrons for bond formation and we know O has six valence electrons, so rest of four electrons exist as two pairs of lone pair over three O atoms.

H has only one electron that electron is used for sigma bond formation with one of the O atoms. So, H has no lone pair in the HClO3 lewis structure.

5.    HClO3 lewis structure formal charge

Due to the presence of different electronegative atoms in the HClO3, we should check the overall charge of the HClO3 lewis structure. This process is called a formal charge. But we assume here all the atoms have the same electronegativity, so there is no difference in electronegativity in the HClO3 lewis structure.

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

Where Nv is the number of electrons in the valence shell or outermost orbital, Nl.p is the number of electrons in the lone pair, and Nb.p  is the total number of electrons that are involved in the bond formation only.

there are three different substituents Cl, O, and H present so we have to calculate the formal charge for them separately.

The formal charge over Cl atoms is, 7-2-(10/2) = 0

The formal charge over O atoms is, 6-4-(4/2) = 0

The formal charge over the H atom is, 1-0-(2/2) = 0

So, from the above calculation, it is evident that each atom in the HClO3 lewis structure is neutral. It is also reflected that the HClO3 lewis structure is also a neutral molecule.

6.      HClO3 lewis structure octet rule

Every s and p block element follow the octet rule after the formation of any bond or any molecule, to gain stability like noble gases. They try to gain the electronic structure like the nearest noble gases. The substituents in the HClO3 lewis structure are formed s and p block elements and they should have followed the octet rule.

The central Cl in the HClO3 lewis structure is from the group 17th element and it has seven valence electrons. It is a p block element, so according to the octet rule, it should complete its octet by completing the valence shell by eight electrons. Those electrons come from accepting others or sharing via a bond with another atom.

Cl makes three bonds with three O atoms via sharing three from its electrons and one from three each O atoms. Now it has six electrons in its valence p orbital and already two electrons that are present in the s orbital so, now it can complete its octet with eight electrons. So, in the HClO3 lewis structure, Cl can complete its octet by forming three-sigma bonds with three O atoms and completing its p as well as s orbital.

Now for H, it has only one valence electron and it is s block element so it needs one more electron to complete its octet. So, when H makes a bond with O to share one electron from its side and one from the O side, then it can complete its octet.

For O atoms there are two types of O atoms present in the HClO3 lewis structure. Two O atoms are attached to the central Cl atom with a double bond and one O atom is attached with a single bond. O atom has six valence electrons and used two electrons for double bonds or two sigma bonds, so O has two bond pair electrons from its side and two electrons from another site which it makes bond with, and the rest of the four lone pairs. So, O atoms also complete their octet by sharing a bond with other atoms in the HClO3 lewis structure.

7.    HClO3 lewis structure angle

The bond angle around the central Cl atom in the HClO3 lewis structure is less than 1200. But the angle around the single-bonded O atoms is nearly 1040.

HClO3 Bond Angle

From the VSEPR theory, we can say that the bond angle for pyramidal structure is nearly about 1200. But the bond angle trigonal planar is 1200. But the bond angle around the central Cl atom is less than 1200, due to there is extensive double bond -lone pairs repulsion occurs.

Due to minimizing that repulsion HClO3 lewis structure adjust its bond angle to some extent and the bond angle decrease. If there is any deviation factor present that is lone pair repulsion or bond pair repulsion then the bond angle of the molecule always decreases than the expected value.

Again, here another bond angle is observed between Cl and H atoms around a single-bonded O atom.

The moiety around the single-bonded O atoms is tetrahedral so the bond angle is expected to be 1090, but there are two lone pairs present so there also repulsion occurs. To minimize the repulsion here also bond angle decreases and is around 1040.

8.    HClO3 lewis structure resonance

ClO3 instead of HClO3 shows a different resonating structure and on the basis of ClO3 resonance structure the acidity of HClO3 is dependent.

HClO3 Resonating Structures

All four are the different resonating structures of ClO3-. Structure IV is the most contributing structure because it has the most stability, due to a maximum number of the covalent bond and the negative charge is present over electronegative Cl atoms.

After that on decreasing the number of covalent bonds structure III, then II and least contributing are I.

Due to the higher number of resonating structures of the conjugate base, the HClO3 lewis structure is a strong acid.

9.    HClO3 hybridization

2p of O and 3p or Cl are different in energy, so they undergo hybridization to form a new hybrid orbital of equivalent energy. In the HClO3 lewis structure, central Cl is sp3 hybridized.

We used the formula to predict the hybridization of the HClO3 lewis structure is,

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.

So, the hybridization of central Cl atoms is,  1/2(5+3) = 4 (sp3)

Structure   Hybridization value  State of hybridization of central atom    Bond angle
Linear      2 sp /sd / pd       1800
Planner trigonal  3sp2              1200
Tetrahedral       4sd3/ sp3          109.50
Trigonal bipyramidal 5sp3d/dsp3           900 (axial), 1200(equatorial)
Octahedral      6sp3d2/ d2sp3      900
Pentagonal bipyramidal7sp3d3/d3sp3             900,720


So, from the hybridization table it is evident if the number of orbital involved in the hybridization is 4 then central atom should be sp3 hybridized.

Let us understand the hybridization of central Cl in the HClO3 lewis structure.

HClO3 Hybridization

From the box diagram, it is evident that we only consider the sigma bond in the hybridization not the multiple bonds.

10. HClO3 solubility

HClO3 is soluble in the following solution,

  • Water
  • CCl4
  • Ethanol
  • Benzene

11. Is HClO3 soluble in water?

HClO3 is a polar solvent and water is also polar so, it is soluble in water (like dissolves like).

12. Is HClO3 an electrolyte?

Yes, HClO3 in aqueous solution dissolved and ionized in cation and anion and carry current, so it is an electrolyte.

13. Is HClO3 a strong electrolyte?

Yes, HClO3 is a strong electrolyte because dissociation in an aqueous solution gives H+ ion which migrates very fast and carries more current so it is a strong electrolyte.

14. Is HClO3 acidic or basic?

The HClO3 has an acidic H atom, so it is acidic.

15. Is HClO3 a strong acid?

Due to the presence of more electronegative atoms, they pull sigma electron density toward themselves, and the release of the acidic proton is very easy so, it is strongly acidic.

16. Is HClO3 polyprotic acid?

No, it has only one proton so it is not a polyprotic acid.

17. Is HClO3 a lewis acid?

There is no vacant site here present for accepting lone pair, so HClO3 cannot be a lewis acid.

18. Is HClO3 an Arrhenius acid?

Yes, it can release an H+ ion, so it is an Arrhenius acid.

19. Is HClO3 or HIO3 stronger?

Cl has larger electronegativity than I, so HClO3 is a stronger acid than HIO3.

20. Is HClO3 stronger than HClO2?

HClO3 has more O atoms than HClO2, so HClO3 is stronger than HClO2.

21. Is HClO3 a binary acid?

No, it is ternary acid.

22. Is HClO3 polar or nonpolar?

HClO3 is a polar compound, as it has a resultant dipole-moment due to its asymmetric structure.

23. Is HClO3 linear?

No, HClO3 is pyramidal.

24. Is HClO3 paramagnetic or diamagnetic?

HClO3 is diamagnetic in nature due to the absence of unpaired electrons.

25. HClO3 boiling point

The boiling point of HClO3 is 190C.

26. Is HClO3 diprotic?

HClO3 is monoprotic.

27. Is HClO3 ionic or covalent?

HClO3 is covalent.

28. Is HClO3 a cation?

No HClO3 is not a cation but H+ is its cation.

29. Is HClO3 stronger than HCl?

No, HCl is stronger than HClO3.

30. Is HClO3 stronger than hclo4?

No, HClO4 is stronger than HClO3 due higher number of O atoms present.

31. HClO3 is stronger than HClO?

Yes, HClO3 is stronger than HOCl.

32. Is HClO3 an oxoacid?

Yes, HClO3 is an oxo acid of Cl.

33. Is HClO3 aqueous?

HClO3 is liquid.


HClO3 lewis structure is a ternary compound and monobasic acid. it is a very strong acid due to the presence higher number of O atoms. It is an example of oxoacid of halogen, Cl.

Biswarup Chandra Dey

Hi......I am Biswarup Chandra Dey, I have completed my Master's in Chemistry. My area of specialization is Inorganic Chemistry. Chemistry is not all about reading line by line and memorizing, it is a concept to understand in an easy way and here I am sharing with you the concept about chemistry which I learn because knowledge is worth to share it.

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