Is SiF4 Polar or Nonpolar: Why, How, Lewis structure, Detailed Explanations


“Is SiF4 polar or nonpolar” is the main descriptive topic in this article. This article would represent the chemistry behind considering the polarity of SiF4. Lewis dot structure of the compound would be relevantly presented in this article as well.

There is a huge contrary explanation about the fact regarding polar non-polar nature of SiF4, Silicon tetrafluoride.  The shape and the bond structure of the compound give reasonable approaches to provide proper consideration about the polarity of SiF4.

Is SiF4 polar or nonpolar?

SiF4 is non-polar. The compound occurs as great example of non-polar compound, which is quite attainable for showing the exceptional compound in the series of the polar compounds.

Silicon tetrafuloride has polar bonds between Silicon and fluorine but the tetrahedral shape eliminates the dipole movement of four Si-F sigma bonds. Otherwise, the dipole nature of the bonds is very strong.

Why is SiF4 nonpolar?

There is a huge reason, which generates complete non-polar nature among Silicon tetrafluoride. That reason is considered as the strong fact for SiF4 to possess zero dipole moment even after having polar bonds.

The high polarity between the bonds made by Silicon and Fluorine can be a great reason for considering the compound as a polar compound. However, the arrangement of the bonds is the reason, which creates a barrier in front of SiF4 for being polar compound.

The arrangement of bonds in the compound is symmetric with even number of bonds. As for being polar the arrangement of bonds in a compound is needed to be asymmetric with would provide huge dipole moment to the compound.

Due to symmetric bond arrangements around the central molecule the dipole moments are cancelled out by the pulling in opposite directions. In SiF4, action takes place, which is obvious in giving non-polar structure to the compound.

The asymmetric distribution of bonds is not able to creates the balance through the pulling effect from each of the atoms at the end of the bonds. Therefore, a certain amount of dipole moment is noticed to take place in the asymmetric compounds. And it makes the compound absolute polar compound.

Silicon tetrafluoride is recognised as a compound which creates “polarised Si delta plus and F delta minus.” Therefore, the bonds could be polarised bonds but the dipole moments are eliminated by the bond arrangements.

Take an overview on the general concept of polar and non-polar compounds.

Lewis structure of SiF4

Octahedral molecular structure of SiF4 is represents that the polarisation takes place inside the bonds. However, the Lewis dot structure expresses the covalent bonding between the elements.

Silicon shares its two electrons from last cell with each of the four Fluorine atom and the fluorine atoms also share two electrons with Silicon. This mutual sharing crates the covalent bonding in between the Silicon and fluorine atoms.

is sif4 polar or nonpolar
Lewis structure shows “is SiF4 polar or nonpolar” from Wikipedia

Silicon tetrafluoride is considered as a Lewis acid. Here the mutual donation of electrons from fluorine and acceptance from Silicon take place, which generates the idea that Si is the Lewis acid, and F atoms are the Lewis bases.

The coordinate covalent bond is created through this reaction. The compound to expand the valances uses the vacant d-orbitals. It is a huge feature, which says that SiF4 is a Lewis acid. The empty d-orbitals are hold by Silicon. Therefore, it cannot be taken as an example of Lewis base.

The drawing process of electron dot structure of the compound depends on the valance possessed by the elements. Valance of Silicon is four and fluorine is seven. Therefore, the total number of valance electron in SiF4 is [4+ (7*4)] = 32. However, by arranging these valance electrons the elements fulfil their octets.

High electronegativity of fluorine does not allow it to be the central atom.  Therefore, in Lewis structure Si stays in the centre. By making four single bonds, four fluorine atoms shared two electrons of each with Silicon.

The Lewis structure is reliable in understating the covalent nature of SiF4. The hybridization is SP3 in the compound.  This structure informs that the chemical bonding of the molecules are formed by following the theory called “Valance shell Electron pair repulsion (VSEPR)”. The molecular geometry gets proper dimension with the help of this theory.

Dipole moment if SiF4?

Dipole moment refers to the concept of measuring the separation of opposite charges in a compound.  This concept is applicable for SiF4 as it has polar bonds and dipole exits among the ionic structure. On the contrary, the measurement of dipole says a exceptional fact about this compound.

The non-polar SiF4 has zero dipole moment, as the dipole moment is cancelled out by the symmetric molecular geometry of Silicon fluoride.  The tetrahedral geometry shows that the binds have absolute dipoles. Nevertheless, the moment cancelled put due to the pulling effect in tetrahedral shape.

Read more about the concept about dipole moment

Frequently Asked Questions (FAQs)

Question 1: Why does SiF4 possess zero dipole moment?

Answer: the dipole moment of the polar binds in SiF4 is eliminated by the tetrahedral molecular geometry of the compound.

Question 2: Why SiF4 is Covalent?

Answer: The covalent characteristic in SiF4 is noticed as the bond between Silicon and Fluorine atoms are formed by the influence sharing method not complete transfer of electrons. Therefore, the bonds are covalent only.  

Question 3: What information shared by the Lewis Structure about the compounds?

Answer: “Valance shell Electron pair repulsion (VSEPR)” theory is informed by the Lewis structure of the compounds. Lewis structure denotes that the molecular geometry is represented by this theory.  This theory provides information about the arrangements of electrons regarding the existence of valance shell of the atoms.

Question 4: Compare the molecular geometries of SiF4 and SF4 according to the polarity.

Answer: SiF4 has covalent bonds between Silicon and Fluorine atoms. The bonds are arranged in tetrahedral shape. Moreover, has no lone pair in its molecular geometry. Sp3 hybridization structure possesses vacant d-orbitals in Silicon.

In SF4, the covalent bonds are present in the structure. There is also four bonds created by fluorine atoms by sharing electrons with Sulphur. The main difference of SF4 bonds with SiF4 is that in the molecular geometry of SF4 a lone pair of sulphur exists. It creates strong dipole moment in SF4. The dipole moments are cancelled out by the pulling effect in the bonds in SiF4.

Question 5: Briefly discuss about the bond arrangements in SiF4.

Answer: In SiF4, the bonds exist in tetrahedral geometry by having dipole but due to tetrahedral shape the dipole moment is found to be zero here. As Fluorine is more electronegative in nature, Silicon holds the centre position in this compound and Fluorine atoms creates single bind with it.

Question 6: How SiF4 is a Lewis acid?

Answer: SiF4 holds a vacant d-orbital in the molecular structure, which makes it an electron donor not an acceptor.  Therefore, it is considered as a Lewis acid not base.

Sarnali Mukherjee

Hi.....I am Sarnali Mukherjee, a graduate from the University of Calcutta. I love to teach and share knowledge on chemistry. I have gradually gained interest in article writing since one year ago. I would love to acquire more knowledge on my subject in the future. Let's connect through LinkedIn: https://www.linkedin.com/in/sarnali-mukherjee-921b59231

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