SF2 Lewis Structure: Drawings, Hybridization, Shape, Charges, Pair and Detailed Facts


SF2 lewis structure comprises sulphur and the most electronegative element fluorine both of which belong to adjacent groups in the periodic table. Their properties are illustrated in this article.

SF2 lewis structure involves 1 sulphur and 2 fluorine atoms. The sulphur atom has 6 valence electrons and the fluorine atom has 7 valence electrons. To complete their octet stability criteria there will be sharing of electrons where each fluorine atom will share 1 electron each with 2 electrons of sulphur. This provides the SF2 lewis structure.

SF2 lewis structure or sulphur difluoride as the name suggests belongs to the class of inorganic compounds. As the atoms involved are non-metals in the composition of SF2 lewis structure so there is sharing of electrons instead of gaining or losing electrons. This leads to the formation of single covalent bonds between sulphur and fluorine. The elemental analysis of SF2 lewis structure shows that the fluorine atom is in dominance with 54.23% contribution and the sulphur atom has 45.77% contribution. 

SF2 lewis structure is not a stable compound and readily decomposed to FSSF3. Many studies have shown strangeness in their bonding abilities. This SF2 lewis structure dimer shows peculiarity in bond behaviour and form recoupled pair bond dyads.

The research conducted by the University of Illinois has proven that SF2 lewis structure dimer does not follow the convention of bond length is inversely proportional to dissociation energy and force constant concept. The two S-F pathways in SF2 lewis structure dimer are completely different from one another so neither the longest nor weakest bond is affected by low dissociation energy.

Apart from this, not much is known about the SF2 lewis structure due to its instability. It can be prepared by a reaction between sulphur dichloride and potassium fluoride. The reaction between mercury(II) fluoride and sulphur dichloride at low pressure can also lead to SF2 lewis structure. Another common method is the reaction between oxygen difluoride and hydrogen fluoride which gives the product SF2 and water as a by-product.

SF2 lewis structure is an electron dot representation which can explain many other characteristics related to it. Discover a step by step method to generate SF2 lewis structure is of significance.

SF2 lewis structure

How to draw the lewis structure for SF2?

Count the number of valence electrons

For drawing the SF2 lewis structure it is important to know the number of valence electrons present in the compound. Here sulphur (Atomic number = 16 and electronic configuration = 2,8,6) has 6 valence electrons. Similarly fluorine (Atomic number = 9 and electronic configuration = 2,7) have 7 valence electrons. So the total number of valence electrons participating in bonding is 6 + 7×2 = 20.

Lookout for central atom

Finding the central atom is the next step in the SF2 lewis structure. The atoms with the least electronegativity are considered for the position of the central atom. In SF2 lewis structure as the formula suggests sulphur is the least electronegative as compared to most electronegative fluorine atoms. So it will be the central atom.

Complete the octet stability

To complete the octet stability criteria of SF2 lewis structure there will be sharing of electrons between sulphur and the fluorine atoms. As both of them are non-metals so they will form covalent bonds. Here 1 atom of sulphur will share their 2 electrons with 1 electron of each fluorine atom forming a single covalent bond between S-F.

Check the formal charge

To confirm the reliability of the SF2 lewis structure it is crucial to calculate the formal charge of each atom involved in chemical bond formation. In the SF2 lewis structure, the formal charge of sulphur and both the fluorine atoms is 0 which confirms the presence and authenticity of the lewis structure.

Moving ahead let’s discuss the properties related to the SF2 lewis structure. These properties are:

SF2 lewis structure shape

The shape and molecular geometry of SF2 lewis structure can be explained with the help of VSEPR theory. Usually, the shape and the molecular geometry of the molecule can vary due to the presence of lone pairs, electronegativity and other related factors.

As far as SF2 lewis structure is concerned the central sulphur atom has 2 lone pairs of electrons and 2 bond pairs with fluorine atoms. Due to the presence of lone pairs on sulphur atoms and the electronegativity of fluorine atoms, there will be repulsion between the lone pairs and bond pairs. As a result, both lone pairs and bond pairs will be pushed away which in turn will push down the bonded S-F.  So due to this activity, the SF2 lewis structure will be of the bent shape but the molecular geometry of SF2 lewis structure will be tetrahedral.

SF2 lewis structure formal charge

The formal charge of each atom is calculated in lewis structure to confirm the stability of the molecule. It is the uniform electric charge distribution on all atoms after chemical bond formation. The lesser the formal charge on the atoms the more stable is the lewis structure. 

The formula used to calculate formal charge is:

FC = V – NBE – 1/2BE

Where V = valence electrons

              NBE = non-bonding electrons

              BE = bonding electrons

FC of fluorine in SF2 lewis structure = 7 – 6 – 2/2 = 0

FC of sulphur in SF2 lewis structure = 6 – 4 – 4/2 = 0

SF2 lewis structure lone pairs

Lone pairs of electrons are those electrons in the valence shell which do not participate in chemical bond formation. Or, we can say they are those electrons which are left after the octet completion criteria are fulfilled. They have a very important role when it comes to finding shape or other properties.

Talking about SF2 lewis structure then the lone pair of central atoms is given importance as they are the deciding factor in other characteristics. In the SF2 lewis structure, the central atom is sulphur and it has 6 valence electrons. After sharing 2 electrons with each fluorine atom there will be 4 unshared electrons. These 4 unshared electrons did not participate in bonding and formed 2 lone pairs of electrons.

SF2 lewis structure hybridization

Hybridization is a phenomenon of mixing atomic orbitals to form new hybrid orbitals with different energies and properties. The concept of hybridisation is based on the valence bond theory.

Coming back to the SF2 lewis structure then we can find its hybridisation by the steric number of the central atom sulphur. The steric number is one of the methods to find hybridisation and its formula is 

Steric number = Lone pair on central atom + no. of atoms attached with the central atom.

In case of SF2 lewis structure, the steric number is = 2 + 2 = 4 So according to that its hybridization is sp3.

SF2 lewis structure resonance

SF2 lewis structure does not show the phenomenon of resonance or mesomerism. This is because sulphur has 6 electrons in its valence shell and that allows it for the arrangement as a molecule. Also in the SF2 lewis structure, there is the absence of double bonds and delocalization of electrons is not possible as it will disturb the octet stability. Hence SF2 lewis structure does not exhibit resonance and only a single structure is responsible for explaining all of its properties.

SF2 lewis structure octet rule

The octet rule is a criterion in the main-group element which decides the stability of the element. The element is stable if there is the presence of 8 electrons in the valence shell. But the majority of the elements do not have 8 electrons in their valence shell hence they are unstable in their elemental form. 

To complete their octet stability they lose, gain or share their electrons with other elements. As far as SF2 lewis structure is concerned then there is sharing of electrons as both the elements are non-metals. Sulphur has 6 valence electrons and fluorine has 7 valence electrons. To achieve stability they need 2 and 1 electron respectively. So 2 fluorine atoms will share each electron with the 2 electrons of the sulphur atom thereby satisfying the SF2 lewis structure octet rule.

Frequently Asked Questions

Is SF2 lewis structure polar or nonpolar?

SF2 lewis structure is polar because it has a bent shape which is non-symmetrical. It also has a non-zero dipole moment. The electronegativity difference between sulphur and fluorine is 1.5 which is more than 0.5 thereby confirming the polarity.

Mansi Sharma

Hello, I am Mansi Sharma, I have completed my master's in Chemistry. I personally believe that learning is more enthusiastic when learnt with creativity. I am a Subject Matter Expert in Chemistry. Let's connect through LinkedIn: https://www.linkedin.com/in/mansi-sharma22

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