Clo3- lewis structure,Characteristics:13 Facts You Should Know

clo3- lewis structure and other important details are going to be discussed in this article.

Chlorate anion, ClO3 monovalent anion which is used as a strong oxidiser. It consists chlorine with three oxygen atoms and an excess negative charge.

Facts about Chlorate anion, ClO3

Chlorate anion is a salt of chloric acid. It’s molecular weight is 83.45g/mol. It has chlorine with three oxygen atoms attached into it. Chlorine exist in +5 oxidation state here. It is a powerful oxidiser which can easily oxidise oxidisable materials. It is found to be an unstable compound.
Chlorates are formed by the reaction of chlorine with hot metal hydroxides. This is a lab method but industry method is also there. Industrially it can be prepared through reacting aqueous NaCl or brine with metal hydroxides.

It combines with certain metals like potassium, sodium, magnesium to form corresponding salts. It is relatively toxic and wet solid in appearance with moisture in it.

Lewis Dot Structure of Chlorate anion, ClO3

The Lewis structure of chlorate anion is drawn through some steps. They are as follows.

  • First count the total number of valence electrons in chlorate anion. Chlorine with seven and oxygen with six electrons. In addition there is one negative charge that is one electron excess. So in total 7+3×6+1 = 26 electrons.
  • Write the central chlorine atom surrounded with three oxygen. Form one bond between chlorine and oxygen. To make the bond there took six electrons so the remaining 20 electrons are distributed equally in all atoms. First distribute with oxygen atom. Distribution should be done in such a way that the atoms obey octet rule.
clo3- lewis structure
Lewis structure of ClO3 –
  • The structure drawn now is not correct. When considering the formal charges it is 2 and -1 for chlorine and oxygen respectively. For stable existence its formal charge is to be zero. So let’s draw a Lewis dot structure with zero formal charges for chlorine and oxygen. The structure is
Stable Lewis structure of ClO3 –

Resonance in Chlorate anion, ClO3

Chlorate anion has more than one structure. So we can say that it undergoes resonance. Resonance is the motion of electrons associated with an atom in a molecule. Such structure obtained as it’s result is resonance structure.

The resonance or resonating structures of chlorate anion is due to the motion of electrons associated with oxygen. That’s results three structures for chlorate anion. It is

Resonance in ClO3

Octet Rule in Chlorate anion, ClO3

Chlorate anion consists of three oxygen atoms with one central chlorine atom. The most stable Lewis structure of this ion can be taken to study whether it follows octet rule or not.

Octet in ClO3

 From the above figure we can see that all the three oxygen has eight electrons in its valence shell. So they completely obeys octet rule. When looking into chlorine atom it has more than eight that is twelve electrons associated with it. So the chlorine atom present here is hypervalent molecule or we can say that chlorine in chlorate ion has expanded octet.

Formal charge in Chlorate anion, ClO3

The formal charge of chlorate anion is calculated by considering its Lewis structure.

Valence electrons in ClO3

Formal charge = valence electrons – No. of electrons – No. of bonds

Formal charge of chlorine = 7-2-5 = 0

Formal charge in oxygen = 6-4-2 = 0

Formal charge in one oxygen with single bond = 6-6-1 = -1

The formal charge of atoms in chlorate anion is zero for two chlorine and two oxygen atoms.

Valence electrons in Chlorate anion, ClO3

The total number of electrons involved in bond making process is called the valence electrons. The total number of electrons involved in bond making of chlorate anion is 26.

Lone pair of electrons in Chlorate anion,ClO3

The lone pairs present in chlorate anion is 8 pairs.
Chlorine contains one pair. Two oxygen atoms has two lone pair each. One of the oxygen has three pairs .

Shape and angle of ClO3

According to VSEPR theory atoms occupies a position around the central atom in such a way to reduce repelsion between the electrons associated with atoms. Chlorate anion is AX3N type molecule. That is A is central atom(Cl), X is atom attached into central atom(Oxygen), N is the number of lone pairs in central atom(1).

The sp3 hybridisation followed by chlorate ion has to be in tetrahedral in shape. But the presence of lone pair in chlorine atoms don’t allows this geometry. There is strong repelsion between the lone pairs in chlorine and oxygen.

To reduce this factor the atoms will stay as far as apart to form triagonal pyramidal geometry with bond angle 1070. The bond length of Cl-O bonds are same and is 1.49 x 10-10m.

Shape and Bond Angle of ClO3

Hybridisation in Chlorate anion, ClO3

The hybridisation in any ionic molecule can be found through the following equation.

          Hybridisation  = ½[ valence electrons – monovalent atom – cationic 

                                     Charge + anionic charge]

Here the valence electrons in chlorine is 7. There is no monovalent atom present here. Cationic and anionic charge is 0 and 1 respectively.

On substituting this values to the above equation then,

Hybridisation = ½[7-0-0+1] = 8/2 = 4

Since four orbitals are involved it may undergo sp3 hybridisation. Due to the presence of lone pair in the central chlorine atom the shape got distorted into triagonal pyramidal shape with bond angle almost 1070.    

Solubility of Chlorate anion,ClO3

Chlorate anion is a negatively charged ion which is found to be soluble in water. It is due to the polar nature of ion. Water is a polar molecule so it will dissolve all other polar substances.                                                                                                                             

Is Chlorate anion, ClO3 Polar or not ?

Chlorate anion is a polar molecule. It’s because of its symmetry. It’s is an un symmetric molecule. A symmetric molecule can’t be polar. The different electronegativity of atoms attached creates a charge separation in between them.

This give arise to dipole moment. When the molecule are symmetrical in structure then it’s dipole moment got cancelled and they will be non- polar. But here the unsymmetrical structure of the molecule don’t allows it’s dipole moment to get cancelled. Hence it is a polar molecule with dipole moment about.

Is Chlorate anion, ClO3 Ionic or not ? 

Chlorate anion is purely an ionic compound. There is a negative charge associated with this molecule indicates that it is an anion. When it combines with electropositive metal then it will form it’s stable salt. So chlorate ion is represented with a negative charge outside the bracket of the molecule. So it is an ionic compound and not covalent in nature.

Is Chlorate anion, ClO3 Acidic or not ?

Chlorate anion is a conjugate base of chloric acid. When it reacts with water it forms chloric acid.

Is Chlorate anion,ClO3 is Tetrahedral or Linear ?

 Chlorate anion is neither tetrahedral nor linear. It is triagonal pyramidal in shape.

Structure of ClO3


Chlorate anion is an inorganic anion obtained by the de protonation reaction of chloric acid. This article explains that it is sp3 hybridised molecule with 26 valence electrons. It exhibits more than one resonance structure. Its molecular geometry is triagonal pyramidal with 1070 bond angle. Chlorate ion is a polar molecule with water solubility and acidic in nature. Its Lewis structure is drawn in this article.

Aparna Dev

Hi... I am Aparna Dev, a chemistry postgraduate with a good understanding of chemistry concepts. I am working in Kerala Minerals and Metals Limited Kollam with experience in the development of electrocatalysts as a part of post graduate thesis. Let's connect through LinkedIn-

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