It is necessary to recognize the Lewis structure of a molecule to understand its physics properties, hybridization, and also shape that the molecule. This day we room going to go through the Lewis framework of I3- or likewise know together Triodide ion together it has a an adverse charge on it. There three molecules of iodine in this molecule and hence the name of the compound are Triodide. For expertise the Lewis framework of the molecule, we should know valence electrons the the iodine molecule.

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Lewis Structure 

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


We have three molecules of iodine right here which together with an extra electron which offers it a negative charge. Therefore the total number of valence electrons are : 7×3 + 1= 22.There room 22 valence electron in total in this molecule. Currently there is one octet rule that every atom follows. As per this rule, every atom should have eight electron in their external orbit. If there room 8 electrons in the outer shell of the central atom, there are two various other atoms that require to complete their octet. Together all the atom will need eight electron in their external shell to complete the octet one electron of the main Iodine atom will be bring away by both the neighbouring Iodine atoms. That method 8-1-1=6.As the electrons will be taken by both the atoms.

So now the valence electron on the main atom of iodine will certainly be six. These 6 electrons will kind the lone bag of electrons that perform not bond. As it develops the pair of electrons now, there will certainly be 3 lone pairs, and also two bond pairs of the electrons as each Iodine atoms has actually a bond v the main atom sharing one electron every in complete there 3 lone pairs and also 2 bond pairs on the central atom.



For understanding the hybridization of any kind of molecule, there is a straightforward formula which deserve to be used. This formula is provided for finding the end the hybridisation number which help in discovering the hybridisation of the molecule.

The hybrid numbers and the hybridisation it identify are declared 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 electrons of the iodine atoms are 7 together there is 7 electron in the outermost shell. The variety of the monovalent atom is two as the two out of 3 iodines space monovalent. Now when we pertained to the fee of the I3- ion it has a an adverse charge for this reason the worth of this an adverse charge will certainly be 1.

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

Another method of recognize the hybridisation of a given molecule is with the aid of lone pairs and valence electrons. The variety of lone pairs in this molecule is 3, and the variety of atoms share valence electrons is 2.Hence, 3+2=5 which likewise determines sp3d hybridisation.

The shape of I3- Ion


The form of the molecule I3- is Linear. There room three Iodine atoms the end of i m sorry one has an extra an adverse charge. As result of this one extra electron there 3 lone bag of electrons and 2 bond pairs making it’s steric number 5. As there room three lone bag on the central Iodide atom, this pairs shot to defeat each other as much as possible. So in order come be away at a higher distance, the pairs take the equatorial positions, and also the various other two Iodine atoms space 180 levels from one another. For this reason the overall shape the the I3- ion is linear.


So here is the tricky component about this ion, an initial of all prefer it as a charge on it we can call it as a polyatomic ion rather of calling the a molecule. Ions space the fees we watch on the molecules. As I3- has actually one electron, this Ion has a an unfavorable charge overall. Molecules have polarity because it has both the dues that are a partially positively fee end and also the partly negatively fee end. Over there is a dipole moment on the molecules relying on the separation of the dues on the molecule. If the distance between both the dues is bigger the dipole minute will likewise be larger.

But when we talk about I3- ion the is a negatively fee ion. Even when us draw, that Lewis framework we execute not see any dipole moment or the polar bond in it as the all at once charge chin is negative on the ion. So the is no polar or nonpolar. However, if you have actually to define the ion, you deserve to use the expression the “ like a polar molecule” since I3- is dissolve in water.

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