SbF5 Lewis Structure: Drawings, Hybridization, Shape, Charges, Pair and Detailed Facts

SbF5 is known as antimony pentafloride. SbF5 lewis structure contains one antimony (Sb) and five flourine (F) atoms in its structure.

Antimony pentafluoride is an oily liquid form compound, viscous in nature and seems colourless. Human eyes and mucous membranes get irritated from its fumes. It is quite hazardous in nature. SbF5 is corrosive on various metals and body tissues. SbF5 considered as very dangerous compound for our tissues, because as it burns it can cause gangrene to any person.

How to draw lewis structure for SbF5?

Chemical formula for antimony pentafluoride is SbF5.

Molecular weight of SbF5 is 216.752 g mol-1.

Molecular geometry of SbF5 is trigonal bipyramidal shape.

SbF52 has sp3d hybridization.

SbF5 is non-polar in nature.

SbF5 lewis structure contains 5 fluorine and 1antimony atom in its structure. It has 1 antimony and 5 fluorine atoms in the SbF5 lewis structure. There are 10 bonding electrons and 30 non-bonding electrons in SbF5 molecule.

When we draw SbF5 lewis structure, first thing is to note all the valence electrons present on it. To count the valence electron just check the positions of group F and Sb atoms in periodic table as antimony belongs to 15th group and fluorine belongs to 17th group of periodic table. So there are five on antimony and seven on fluorine valence electrons respectively.

So, Total valence electrons on Sb = 5

Total valence electrons on F = 7

So, total valence electrons for SbF5 lewis structure = 5 (Sb) + 7×5 (F5) = 40

SbF5 lewis structure
SbF5 lewis structure showing valence electrons

Least electronegative atom from SbF5 structure should be at central position in the structure because they easily share electrons with other atoms attached with it. In SbF5 compound antimony electronegativity is 2.05 and fluorine’s electronegativity is 3.98. So it seems that electronegative of antimony is lesser than fluorine. That’s why central position is occupied by antimony element covered by five fluorine atom in SbF5 lewis structure.

SbF5 2
SbF5 lewis structure showing antimony (Sb) at central position

Next point is the connection of all the atoms by bonding with each other. So, there is a need to draw a single bond (Sb-F bond) within 1 Sb and 5 F elements to attach them with each other. That means five single bonds should be drawn connecting to central antimony atom with five fluorine atoms.

Now, do the calculation of valence electrons in SbF5 lewis structure, as there are two electrons in 1 single bond. Here, five single bonds get formed in SbF5 molecule. Therefore, 10 valence electrons were used in drawing SbF5 lewis structure from the total 40 valence electrons present.

Hence, 40 – 10 = 30 valence electrons

So, here thirty valence electrons left for bonding.

SbF5 3
SbF5 lewis structure forming single bonds between antimony and fluorine

Now we have to find the total electron pairs. There are 40 valence electrons total and it gets divided by the number 2 to get total electron pair count.

Formula is: Total electron pairs = total no. of valence electrons / 2

Hence, total electron pairs = 40 ÷ 2 = 20

SbF5 lewis structure octet rule

Octet rule means having eight electrons in outermost valence shell orbital. There should be eight electrons on fluorine atom present in outer shell of SbF5 lewis structure. Antimony has an extended octet in SbF5, as has 5 Sb-F bonds i.e. 10 electrons in outer shell instead of 8 electrons.  All the valence electrons left will go to fluorine atom till it have electrons to complete the octet.

So, 10 electrons are engaged in forming five bonding pairs with 5 F atoms from total 40 valence electrons of SbF5 molecule. Also 15 lone electron pairs out of 30 remaining electrons get shared equally within 5 fluorine atoms means per fluorine atom has 3 lone electron pairs.

SbF5 4
SbF5 lewis structure showing complete octet of fluorine and extended octet of antimony

Dots in the above image shows six lone electron pairs and a bond having two electrons so total eight electrons on fluorine, means complete octet.

So here it is determined that the octet rule is not obeyed by SbF5 lewis structure because of presence of 10 electrons on central Sb atom having extended octet.

SbF5 lewis structure formal charges

When there is less formal charge on atoms the lewis diagram is more stable. Here is a given formula to evaluate the formal charge on atoms present in lewis diagram.

Formal charge on atoms= (valence electrons – lone pair of electrons – ½ bonding electrons)

First count the formal charge on five fluorine atoms of SbF5 molecule. Fluorine has equal lone pair and bonded pair electrons, so calculate the formal charge of single fluorine atom.

Fluorine atom: Fluorine Valence electrons = 07

   Lone pair electrons on fluorine= 06

Fluorine atom having Bonding electrons = 2 (one single bond)

Formal charge on Fluorine = (7 – 6 – 2/2) = 0

So, so there are zero formal charges on five fluorine atoms.

Antimony atom: Central Sb atom has Valence electron = 05

                          Central Sb atom has Lone pair electrons = 00

                          Central Sb atom has Bonding electrons =10 (five single bonds)

Antimony atom has Formal charge = (05 – 0 – 10/2) = 0

So, SbF5 lewis structure has zero formal charge for the central antimony atom.

SbF5 lewis structure lone pairs

There is six lone pair electrons on each fluorine atom of SbF5 molecule, as there are five fluorine atoms are present so total 30 lone pair electrons are there.

Likewise there is no lone electron pair on the central antimony atom of SbF5 lewis structure, because antimony has extended octet i.e. 10 electrons involved in five single bonds with F atoms.  Therefore, SbF5 lewis structure has (6×5) F + (0) Sb = 30 lone electrons pair. Therefore, there are total thirty lone pair electrons on Sbf5 lewis structure.

SbF5 lewis structure shape

Molecular geometry of SbF5 structure shows trigonal bipyrimidal shape of SbF5 lewis structure. As per VSEPR theory bond pair electrons have no repulsion if lone electron pairs are not present in any structure. So, trigonal bipyrimidal shape forms in SbF5 lewis structure as 5 Sb-F bonds form within structure with 90 degree bond angle within it. AX5N0 is the generic formula for SbF5 according to VSEPR theory. Hence there are five electron density sections of five bond pairs and no lone pairs. SbF5 can only get shipped under cylinder. If it has prolonged exposure to heat, it can violently rupture cylinders and rocket.

SbF5 Hybridization

Hybridization of SbF5 lewis structures can be assigned by the steric number of its central antimony atom.

Addition of total bonded atoms connected with middle (central) atom and its lone pair of electrons is known as steric number..

Steric number of SbF5 = (total number of bonded atoms fixed with antimony antimony’s lone electron pair)

SbF5 lewis structure shows that antimony and five fluorine atoms connected to each other with bonding have zero lone electron pairs on it.

So, SbF5 steric number = 5 + 0 = 5

SbF5 lewis structure has calculated value of steric number is 5, showing sp3d hybridization of Sb atom in SbF5 molecule.

SbF5 lewis structure resonance

SbF5 lewis structure cannot show any kind of resonance, the resonance structure of SbF5 is not possible because there no any formal charge on SbF5 molecule structure. Even the SbF5 have only single bonds in its structure there is no multiple bonds like triple bond or double bond. SbF5 have five single covalent bonds attached to five fluorine atoms and even the antimony atom have extended octet. For all the above reasons we consider that the SbF5 is a stable molecule in nature and cannot form any hybrid structure.

Also Read: