SbCl5 is known as antimony pentachloride. SbCl5 lewis structure contains one antimony (Sb) and five chlorine (Cl) atoms in its structure.
SbCl5 is a liquid form compound looks like a reddish yellow fuming liquid having pungent smell. Human eyes and membrane of mucous get irritates from its fumes. SbCl5 liquid solidifies at 37 degree faraday. It is corrosive to various tissue and some metals. Here, we are discussing about the SbCl5 lewis structure.
How to draw lewis structure for SbCl5?
There are two main rules for drawing lewis structure of any molecule or chemical compound.
- First is to count or note the number of valence electrons of each element or atom present in the molecule or chemical compounds or ions. If the ions are there then count the charges on it.
- Complete the octet of every element or atom by putting electron pair after bonding of atoms to each other i.e. every element have eight electrons in its outer orbit, except hydrogen which has only two electrons in its outer shell. Sometimes the molecule forms double or triple bonds. Multiple bonds only form with some elements like oxygen (O), carbon (C), nitrogen (N), phosphorus (P) and sulphur (S) and rarely with Cl.
Chemical formula for antimony pentachloride is SbCl5.
Molecular weight of SbCl5 is 299.0 g mol-1.
Molecular geometry of SbCl5 is trigonal bipyramidal shape (in liquid).
SbCl52 has sp3d hybridization.
SbCl5 is non-polar polar in nature.
Antimony pentachloride i.e. SbCl5 lewis structure consists of mainly two elements antimony and chlorine. There is one antimony atom and five chlorine atoms are present the SbCl5 lewis structure. SbCl5 lewis structure has ten bonding electrons and thirty non-bonding electrons. It is quite easy to draw the SbCl5 lewis structure.
For drawing the SbCl5 lewis structure first most is to count the number of valence electrons present in the structure, i.e. count the valence electrons of each element present in the structure. So, count the valence electrons present on antimony atom and chlorine atoms.
For counting the valence electrons of any atom or element check its position in the groups of periodic table. As the antimony element present on the fifteenth group (15th group) of the periodic table and the chlorine element present on seventeenth group 17th group) of the periodic table. So antimony has five and the chlorine has seven valence electrons present on it.
Therefore, Total valence electrons for antimony = 5
Total valence electrons for chlorine = 7
So, total valence electrons for SbCl5 lewis structure = 5 (Sb) + 7×5 (Cl5) = 40
Second is to choose the least electronegative element of the SbCl5 molecule to put in the central position during drawing the lewis structure, as they are more ready to share electrons with the neighbouring surrounding elements or atoms. In this molecule electronegativity of antimony is 2.05 and electronegativity of chlorine is 3.16. So the antimony is less electronegative in nature than chlorine. So, antimony should be in the central position of the structure surrounded by five chlorine atoms.
Third point is to connect all the atoms with each other by bonding. So draw single Sb-Cl bonds between one antimony and five chlorine atoms to connect them with each other. Means draw five single bonds between all the five chlorine with central antimony atom.
Now count the below SbCl5 lewis structure valence, one single bond has two electrons. In SbCl5 lewis structure there is the formation of five single bonds. So, from the total forty valence electrons, ten valence electrons get used to draw the SbCl5 lewis structure.
Therefore, 40 – 10 = 30 valence electrons
So, there are more thirty valence electrons have remaining for bonding.
Now we have to find the total electron pairs. We have total fourty valence electrons and this value gets divided by two to count total electron pairs.
Therefore, total electron pairs = total number of valence electrons ÷ 2
Hence, total electronpairs = 40 ÷ 2 = 20
SbCl5 lewis structure octet rule
SbCl5 lewis structure octet rule tell us about the completion of octet of outer atoms. Valence shell of any atom containing eight electrons is known as octet. SbCl5 lewis structure having five chlorine element as an outermost atoms and there is a need of eight electrons to complete the octet of chlorine atoms in its valence shell. Here, the antimony atom is in extended octet as antimony has five Sb-Cl bonds means there are ten electrons in its outermost shell rather than eight electrons. Then, all the remaining valence electrons should put on the chlorine atom till they have eight electrons to complete the octet.
Now, from the total fourty valence electrons of SbCl5 lewis structure ten electrons shared by central Sb atom in five bonding pairs with five Cl atoms. Then the remaining thirty electrons means fifteen lone pair of electrons gets distributed in five Cl atoms i.e. three lone pair of electrons for each five Cl atoms.
Now the five chlorine atoms in the SbCl5 lewis structure has completed its octet as they all have eight electrons in its valence shell. [Dots represented six electrons on chlorine atoms and two electrons as a five single bond with antimony].
So we conclude that the SbCl5 lewis structure does not obey the octet rule as the central antimony (Sb) atom has ten electrons means extended octet.
SbCl5 lewis structure formal charges
The stability on any lewis diagram is more when atoms have less formal charges. There is a formula to calculate formal charge on any atom in lewis diagram.
Formal charge = (valence electrons – lone pair of electrons – ½ bonding electrons)
First we should count the formal charge on all five chlorine atoms of SbCl5 lewis structure. There are equal lone pair electrons and bonded pair electrons on chlorine atoms of the structure so let us just we can count the formal charge of only one chlorine atom.
Chlorine atom: Valence electrons for Cl = 07
Lone pair electrons for Cl = 06
Bonding electrons with Cl = 2 (one single bond)
Formal charge of Cl = (7 – 6 – 2/2) = 0
So, all the five chlorine atoms have zero formal charges.
Antimony atom: Valence electron for central Sb atom = 05
Lone pair electrons on central Sb atom = 00
Bonding electrons around central Sb atom =10 (five single bonds)
Formal charge of Sb = (05 – 0 – 10/2) = 0
So, the central antimony atom in SbCl5 lewis structure has zero formal charge.
SbCl5 lewis structure lone pairs
As we see the SbCl5 lewis structure, we can see there are six lone pair of electrons on each of the outermost chlorine atoms of SbCl5 lewis structure, so there are total thirty lone pair of electrons on all the five outer chlorine atoms.
Similarly the central antimony atom of SbCl5 lewis structure has zero lone pair of electrons in its valence shell. As antimony has complete its octet with extended electrons as it has five bonds with Cl means 10 bonding electrons. So, Sb has extended octet and the SbCl5 lewis structure has 6×5 + 0 = 30 lone pair of electrons. Therefore, the total number of lone pair of electrons in SbCl5 lewis structure is thirty.
SbCl5 lewis structure shape
The SbCl5 lewis structure has trigonal bipyramidal shape as per its molecular geometry. The trigonal bipyramidal shape is due to the central antimony atom gets attached with five bond pairs. So, VSEPR theory says there is no repulsion between the bond pair electrons as there is no lone pair of electrons present. So, there is a bond angle of 90 degree within each Sb-Cl bond. VSEPR theory gives AX5N0 generic formula for SbCl5.
As the central antimony atom of SbCl5 lewis structure has only five bond pairs of electron and no lone pair of electrons means having five sections of density of electrons, so it has trigonal bipyrimidal molecular geometry and square pyrimidal electron geometry due to 90 degree bond angle.
SbCl5 lewis structures hybridization is found by its central antimony atoms steric number.
Sum of total number of bonded atoms attached with central atom and lone pair of electrons present on it is known as steric number.
Steric number of SbCl5 = (no. of bonded elements or atoms attached with antimony + lone pair of electrons on antimony)
According to the SbCl5 lewis structure, antimony is attached with five chlorine atoms have zero lone electron pairs on it.
So, SbCl5 steric number = 5 + 0 = 5
As the calculated steric number of SbCl5 lewis structure is five, so it has sp3d hybridization of antimony in SbCl5 structure.
SbCl5 lewis structure has about 90 degree angle. The central antimony atom has no lone pair of electrons due to which the five chlorine atoms are on 90 degree bond angle with each other.
SbCl5 lewis structure resonance
In resonance structure electrons distribution vary from one structure to another structure. As we see the rules to draw the resonance structure of any lewis structure, there is a need of multiple bonds in the structure and the neighbouring atom has at least one lone pair of electron. If these conditions get fulfil in any structure we can draw its resonance structure by distributing the electrons and charges of atoms in that structure.
If we talk about the SbCl5 molecule resonance structure, the resonance structure of SbCl5 molecule is not possible because it does not have any formal charge on it and also it does not have any multiple bonds (double or triple bonds) in the SbCl5 lewis structure. SbCl5 molecule has zero formal charge and the central antimony atom attached with five chlorine atoms with single covalent bond and even the octet of five outer chlorine atoms is complete and central antimony atom has extended octet. So SbCl5 molecule can consider a stable molecule which does not form any resonance hybrid structure of it.
Polarity of SbCl5 lewis structure
SbCl5 lewis structure has trigonal bipyrimidal geometrical shape due to which it is non-polar in nature. Due to the trigonal bipyrimidal shape of SbCl5 molecule it has some net dipole moment; even the Sb-Cl bond is non-polar because it has very high electronegativity difference between antimony and chlorine atoms. So, SbCl5 is non-polar we can say.
Chlorine has electronegativity 3.16 and antimony has electronegativity 2.05. So antimony and chlorine has the electronegativity difference of 1.11. As per the Pauling’s scale, Sb-Cl bond has very high electronegativity difference which is more than 0.5, so it is non-polar in nature.
As the chlorine atom is quite more electronegative in nature than antimony atom, can cause quite a small negative charge on chlorine atom and small positive charge on antimony atom. Due to this charge separation, the dipole arises within the bond and it is not able to cancel out because of the SbCl5 trigonal bipyrimidal-shaped structure. But this dipole moment is so big due to very high electronegative difference of Cl and Sb. As a result of this SbCl5 molecule is non-polar in nature as there is symmetrical or equal distribution of polar bonds.