In this article we discuss about the Lewis Structure of ICL5.
ICL5 is prepared by the reaction of chlorine (Cl2) and iodine (I2) at a particular stoichiometric ration. It is an inter halogen compound. Inter halogen compound are those which are composed of more than one halogen atom. Basically Icl5 belongs to the category of poly halides.
In the Lewis structure of Icl5 we see that as iodine becomes larger in size and less electronegative than cl it goes In the center of the Lewis structure.
Iodine has seven valance electrons out of which five electrons take part In covalent bonding with cl atom and forms five covalent chemical bonds and still one electron pair there on iodine atom which does not take part in bonding with cl atom and exist as lone pair of electron. Chlorine atom has also 7 electrons in their valance shell out of which only 1 electron make covalent bond with central iodine atom and remaining 6 electrons present as lone pair of electron on cl atom.
ICl5 Lewis Structure Resonance
Resonance means shifting of electron pair from one atom to another atom and the structure obtained by this process is called resonating structure.
ICl5 has 6 resonating structure in which each I-CL bond gets partial double bond character by the process in which CL atom donate its lone pair of electron into vacant d orbital of iodine atom to form p(pi)-d(pi) back bonding.
ICl5 Lewis Structure Shape
According To VSEPR theory the shape of Icl5 is square pyramidal in which iodine is the central atom around which five chlorine atoms surround it. As lone pair present in the central I atom the ideal octahedral geometry becomes distorted. If lone pair is not present in ICL5 the shape becomes octahedral but as lone pair is present the shape becomes distorted and the actual shape is square pyramidal.
ICl5 Lewis structure Formal Charge
The formal charge on any atom 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 Icl5 = 7-10/2 -2=0
Formal charge on each CL atom in Icl5= 7-2/2-6=0
Hence formal charge on both I and CL atom in ICL5 are zero which means that the compound is neutral.
ICL5 Lewis Structure Angle
ICL5 has distorted octahedral geometry hence normal octahedral bond angle 900 does not attained here. Due to repulsion between lone pair of electron on central I atom and bonding electron pair on I-CL bond, CL-I-CL bonds angle slightly decreased from 900 to 81.90 to minimize the lone pair- bond pair repulsion.
ICL5 Lewis Structure Octet Rule
In the Lewis structure of ICL5 we see that each CL atom has 8 valance electrons and complete its octet. In ICL5 Iodine atom forms 5 I-CL bonds and each bond contains 2 electrons. There is also a lone pair that present on central I atom making a total of 12 electrons around I atom. As iodine is a member of third period we know that third period element can increase their octet more 8 electrons. Hence according to octet rule ICL5 is a stable compound.
ICL5 Lewis Structure Lone Pair
The valance electron that does not take part in bonding is defined as lone pair of electron or nonbonding electrons.
The formula through which we can calculate the lone pair of electron is given below:
No of lone pairs= Total no of valance electron of the atom-no of bonds formed by that atom
In ICL5, Lone pair present on I atom=7-5=2 i.e. 1 lone pair
Lone pair present on each CL atom=7-1=6 i.e. 3 lone pair
These lone pairs are shown in the Lewis structure of ICL5 on the given atoms as dots.
Hybridization is the process of mixing of same energy atomic orbitals to form an equal number of mixed orbitals/hybrid orbitals.
The ground state valance shell electronic configuration of is 5s25p5. In the ground state of I we see that there is only one unpaired electron and to make the formation of ICL5 feasible 5 unpaired electron is needed. In the excited state I send its 2 p electron into d orbital making a total of 5 unpaired electrons. In the next step 5 CL atoms give their one unpaired electron to form 5 I-CL covalent sigma bonds and sp3d2 hybridization takes place according to VSEPR theory.
ICL5 mainly used in making water and oil repellent emulsions which is used for the treatment of textiles and leathers. It is also used in making water repellent paper. Due to its insulating properties it is used in electric motors.
Is ICL5 Ionic or Covalent?
ICL5 is a covalent compound. This is because this compound is formed by covalent sigma bonds. In the formation of ionic compound there occurs shifting of electron from electropositive atom to electronegative atom.
In ICL5 it is not possible due to less electronegative difference between I and CL atom. Here in this compound mutual sharing of electrons take place between I and CL atom to form sigma bonds so that no ions is formed. Hence it is a covalent compound.
Is ICL5 stable?
ICL5 is an unstable compound. This is because large cl atoms surrounds central Iodine atom so that severe steric crowding takes place in this compound and dissociates. Also I-CL bonds are not too strong to make the compound stable due to poor orbital overlap between I and CL atom.
Due to these two reasons this compound is not too stable
FAQS about ICL5
Is ICL5 polar in nature ?
A compound is polar when its dipole moment becomes not equal to zero. The electronegativity of I and CL is 2.66 and 3.16 respectively that why I-CL bond moment lies towards CL atom. Hence electronegativity difference occurs between I and CL. In the square pyramidal structure of ICL5 4 CL atoms lying in the same square plane and hence 4 I-CL bond moments cancel each other. But one I-CL bond moment still exist for which dipole moment of ICL5 does not equal to zero. Hence it is polar in nature.
Which type of crystal Structure ICL5 have?
ICL5 Has monoclinic crystal structure.