It is important to know the Lewis framework of a molecule to recognize its physics properties, hybridization, and shape the the molecule. This particular day we are going come go through the Lewis framework of I3- or additionally know as Triodide ion as it has actually a negative charge ~ above it. There 3 molecules that iodine in this molecule and also hence the name of the compound room Triodide. For expertise the Lewis structure of the molecule, we should recognize valence electrons that the iodine molecule.

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Lewis Structure 

Lewis structure is the representation of the electron of the molecules. There are lone pairs and also valence electrons which assist in identify the hybridization and shape that the molecule. Together there space molecules that Iodine, one molecule of Iodine will be in the centre. Also, iodine is in the seventh team of the routine table and also has 7 valence electrons in its outer orbit.


We have actually three molecule of iodine below which together with an extra electron which offers it a an unfavorable charge. For this reason the total number of valence electrons space : 7×3 + 1= 22.There are 22 valence electron in complete in this molecule. Currently there is an octet dominance that every atom follows. As per this rule, every atom should have actually eight electron in their outer orbit. If there are 8 electrons in the external shell that the main atom, there are two various other atoms that require to finish their octet. Together all the atoms will call for eight electron in their outer shell to finish the octet one electron that the main Iodine atom will be bring away by both the adjoining Iodine atoms. That method 8-1-1=6.As the electrons will be taken by both the atoms.

So currently the valence electrons on the main atom of iodine will be six. These six electrons will form the lone pairs of electron that do not bond. Together it forms the pair of electron now, there will be 3 lone pairs, and two bond pairs of the electrons together each Iodine atoms has actually a bond with the central atom sharing one electron each in full there 3 lone pairs and also 2 bond pairs on the central atom.



For learning the hybridization of any type of molecule, there is a straightforward formula which have the right to be used. This formula is supplied for finding the end the hybridisation number which helps in discovering the hybridisation that the molecule.

The hybrid numbers and also the hybridisation it identify are stated as follows:

2: sp hybridisation3: sp2 hybridisation4: sp3 hybridisation5: hybridisation

The formula for finding the number is,Hybridization Number: variety of valence electron + monovalent + (negative charge) – (positive charge)/2The valence electron of the iodine atoms are 7 together there is seven electron in the outermost shell. The variety of the monovalent atom is 2 as the 2 out of three iodines space monovalent. Currently when we involved the charge of the I3- ion it has a negative charge for this reason the value of this an adverse charge will be 1.

Now location all the worths according to the formula,7+1+2/2=10/2=5Thus the hybridisation number is 5 which means it’s hybridisation is sp3d.

Another method of finding the hybridisation of a provided molecule is through the assist of lone pairs and valence electrons. The number of lone pairs in this molecule is 3, and also the variety of atoms share valence electrons is 2.Hence, 3+2=5 which additionally determines sp3d hybridisation.

The form of I3- Ion


The form of the molecule I3- is Linear. There room three Iodine atoms the end of which one has actually an extra an unfavorable charge. Due to this one extra electron there 3 lone pairs of electrons and 2 bond bag making that steric number 5. As there room three lone pairs on the central Iodide atom, these pairs shot to defeat each various other as much as possible. Therefore in order come be far at a greater distance, the pairs take it the equatorial positions, and also the various other two Iodine atoms space 180 degrees from one another. Thus the as whole shape the the I3- ion is linear.


So right here is the tricky part about this ion, very first of all choose it as a fee on it us can speak to it as a polyatomic ion rather of calling it a molecule. Ions space the fees we watch on the molecules. As I3- has one electron, this Ion has actually a an adverse charge overall. Molecules have actually polarity because it has actually both the dues that space a partly positively charged end and the partially negatively fee end. There is a dipole minute on the molecules depending upon the separation of the charges on the molecule. If the distance between both the dues is bigger the dipole minute will also be larger.

But once we talk about I3- ion it is a negatively charged ion. Even when we draw, that Lewis structure we do not see any type of dipole minute or the polar bond in it together the all at once charge chin is negative on the ion. So that is no polar or nonpolar. However, if you have to describe the ion, you have the right to use the phrase the “ favor a polar molecule” since I3- is soluble in water.

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In concluding remarks, to sum up, this whole article, I3- is a polyatomic ion that has 22 valence electrons, 3 lone pairs, 2 link pairs, and also sp3d hybridization. The is linear in shape and also has no polarity.