SnF2 Lewis Structure: Drawings, Hybridization, Shape, Charges, Pair And Detailed Facts


In this article, “snf2 lewis structure” drawing of lewis structure, hybridization, shape, formal charge calculation with some detailed explanations on SnF2 are discussed below.

SnF2 or stannous fluoride is a white monoclinic crystalline compound. The hybridization of Sn is sp2 with two bond pair and one lone pair. It is a neutral compound with a boiling point 8500C and melting point 2130C. The structure of SnF2 is angular with a bond angle less than 1200.

The main outlook of this article is to explain some relevant topics on SnF2 through the following points.

How to draw lewis structure for SnF2?

Lewis structure is one type of structural representation in which nonbonding electrons are shown around the respective atoms. It has a great significance in inorganic chemistry because this structural representation helps to determine the number of electrons participating in bond formation or remain as nonbonding electron pairs.

The steps of drawing lewis structure of any molecule is discussed below-

  1. Determining valance electron is the most important step. Sn has total four electrons in its valance shell (n=5).
  2. To determine the number of bonding electrons, total covalent or ionic bonds present in the molecule should be determined. In SnF2, two covalent bonds (sigma bond) are present between Sn and two fluorine atoms.
  3. In the third step, nonbonding electrons are counted. Sn    has total two electrons or one electron pair who do not participate in bond formation and each of the chlorine atom has six or three pair of electrons remain as nonbonding.

SnF2 Lewis Structure Shape

The word “structure” and shape are almost similar word. But if any repulsion is present in that molecule then structure and shape will not be same. Shape of any molecule can be decided by two main factor-

  • Hybridization of central atom
  • Repulsion

Repulsion can be different types but is structure or shape determination, three types of repulsion play significant role. They are-

  • Lone pair-lone pair repulsion
  • Lone pair -bond pair repulsion
  • Bond pair-bond pair repulsion

The increasing order in the magnitude of the above repulsion is-

Bond pair-bond pair repulsion < Lone pair -bond pair repulsion < Bond pair-bond pair repulsion

In SnF2, Sn has one lone pair and this lone pair is involved in lone pair-bond pair repulsion with the bonding electrons of Sn-Cl bond. Due to this repulsion, bond angle between two Sn-Cl bond becomes lesser than the ideal bond angle. Due to having one lone pair, no lone pair-lone pair repulsion is involved in SnF2. Bond pair-bond pair repulsion can open up the bond angle but lone pair-bond pair repulsion predominates over the bond pair-bond pair repulsion. Thus, actual bond angle slightly lesser than the proper bond angle (1200). Thus, the shape of SnF2 is angular or v-shaped.

Shape of SnF2

SnF2 Lewis Structure Formal Charges

Calculation of formal charge is done to make sure if the molecule is a charged species or a neutral one. Calculation of formal charge of each of the atom in a molecule is carried out using the formula discussed below-

  • Formal charge = Total number of valance electrons – number of electrons remain as nonbonded – (number of electrons involved in bond formation/2)
  • Formal charge of Sn = 4 – 2 – (4/2) = 0
  • Formal charge of each of the fluorine atom = 7 – 6 – (2/2) = 0

The valance shell electron configuration of Tin (Sn) and fluorine (Cl) are 5s2 5p2 and 2s2 2p5.

 SnF2 Lewis Structure Lone Pairs

Those valance electrons do not participate in bond formation or those valance electrons who are not bonding electrons are defined as lone pairs or nonbonding electrons. Thus, the working formula of calculating of lone pairs or nonbonding electrons is-

  • Lone pair or nonbonded electron = Total number of valance electron – number of bonded electrons.
  • Nonbonding electrons of Sn = 4 – 2 = 2 or one lone pair
  • Nonbonding electron of each of the fluorine atom = 7 – 1 = 6 or three lone pairs.

These electrons are shown in the lewis structure as dots around the atoms.

SnF2 Hybridization

The term “hybridization” is introduced in chemistry to explain the mixing of atomic orbitals and formation of bonds. Orbitals having comparable energy difference participate in hybridization.

In SnF2, central atom Sn is sp2 hybridized with a bond angle less than 1200. In this hybridization, Sn shares its two valance electrons from 5p orbital with the 2p electron of fluorine. The 5s orbital and 5p orbital of Sn are involved in sp2 hybridization with fluorine. Total two bond pair (two sigma bonds between Sn and two F atoms) and one lone pair are in SnF2 structure. These lone pair or nonbonding electrons belong to 5s orbital of Sn.

Hybridization of SnF2

As 5s and 5p orbitals of tin participate to form the stannous fluoride, the hybridization of Sn is sp2.

SnF2 Lewis Structure Octet Rule

 Octet rule in chemistry is a rule which states that any molecule should have such type of electron configuration in its valance shell that it has the nearest noble gas electron configuration. This special electronic arrangement has an extra stability factor.

Now it’s time to check if SnF2 obeys octet rule or not because all atoms in a molecule does not obey octet rule. In SnF2, central atom tin (Sn) does not satisfy octet rule. The reason behind this is that after bond formation with two fluorine atoms Sn has six electrons in its valance shell (two nonbonding and four bonding electrons). This is not the electron configuration like its nearest noble gas, Xe (5s2 5p6).

But fluorine obeys octet rule because it has seven valance electrons and after bond formation with Sn it will have eight electrons in its outer most shell, which resembles the electron configuration Ne (2s2 2p6).

SnF2 Polar or Nonpolar

SnF2 is definitely a polar compound. It is angular shaped. Thus, one Sn-F bond moment cannot be cancelled by another Sn-F bond in SnF2. The dipole moment can be cancelled out if the bond angle between two Sn-F bond will be 1800 and the shape will be linear.

Due to this v-shaped structure of SnF2, it has a permanent dipole moment. In SnF2, both the Sn-F bonds as well as the whole molecule is polar.

SnF2, a polar molecule

Frequently Asked Questions (FAQ)

What are the uses of SnF2?

Answer: SnF2 is basically used in toothpaste to prevent dental problems.

Is SnF2 dissolved in water?

Answer: Yes, it is readily dissolved in water. The solubility of SnF2 in water is 35g/100 ml in 20o C.

Aditi Roy

Hello, I am Aditi Ray, a chemistry SME on this platform. I have completed graduation in Chemistry from the University of Calcutta and post graduation from Techno India University with a specialization in Inorganic Chemistry. I am very happy to be a part of the Lambdageeks family and I would like to explain the subject in a simplistic way. Let's connect through LinkedIn-https://www.linkedin.com/in/aditi-ray-a7a946202

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