Hybridization of SF₄ (Sulfur Tetrafluoride)

The process of mixing of atomic orbitals belonging to the same atom of slightly different energies so that a redistribution of energy takes place between them resulting in the formation of new sets of orbitals of equivalent energies and shape is called hybridization. The new orbitals in this form are known as hybrid orbitals. Like pure orbitals the hybrid orbitals are used in Bond formation. Hybridization is a hypothetical concept and has been introduced in order to explain the characteristic geometrical shapes of polyatomic molecules.

What is the Hybridization of SF₄?

SF₄ has only one lone pair and four sigma bonds of F. The central atom is S. So, to explain in simple terms, its bonding regions are four having one lone pair.

There are 34 valence electrons and 5 electron pairs. These five valence atomic orbitals present on the middle atom S are hybridized to resultantly from five sp³d hybrid orbitals. There are four of the hybrid orbitals overlapped with 2P-orbitals. After this complete process, the last hybrid orbital holds a lone pair.

During SF₄ formation, the sulfur atom will produce bonds with each of the fluorine atoms where 8 valence electrons are used. Besides, the 4 fluorine atoms will have 3 lone pairs of electrons in their octet, which will utilize 24 valence electrons further. Besides, two electrons will be placed as a lone pair in the sulfur atom. Now, we can determine the hybridization of Sulfur by considering the number of regions of electron density. 

When bonding occurs, there is a formation of 4 single bonds in Sulfur, and it has only 1 lone pair. By this, we can say that the number of electron density regions is 5.

The S atom in the middle containing the 5 valence atomic orbitals is hybridized to form five sp³d hybrid orbitals. In the 2P-orbitals, 4 hybrid orbitals are overlapped, and the fifth orbital has a lone pair. It will also help in determining the hybrid orbitals count used by the atom by knowing the steric number. Sulfur will use 5 orbitals, including 1 3s-orbital, 3 3p-orbitals, and 1 3d-orbital.

Let us have a look at the Molecular properties of Sulfur Tetrafluoride.

Molecular properties of Sulfur Tetrafluoride

Molecular Geometry of SF₄:

Before going to understand the molecular geometry of SF₄, let us understand What Molecular Formula? The molecular formula is the varieties and number of particles available in the atoms’ group. Here, as we are discussing SF₄, the SF₄ is a Molecule, and It covers an AX₄E species.

The 3-dimensional arrangement of atoms or fragments which create a molecule by getting together is called Molecular Geometry. It can be specified regarding the bond lengths or bond angles.

 It also regulates many properties, such as 

• Reactivity

• Polarity

• Color

• Biological Activity

• Magnetism

There are various types of Molecular structures such as linear, tetrahedral, bent, octahedral, trigonal pyramidal, trigonal planar, and more. SF₄ covers under the ‘Trigonal Bipyramidal’ structure because of its electron arrangements.

SF₄ Lewis Structure

Lewis Structure is a diagrammatic representation that shows the atoms’ bonding represented by the chemical symbols and the electrons’ lone pairs in some specific molecule. It is linked to valence electrons (associated with an atom).

The SF₄ hybridization structure looks as given below.

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The SF₄ Lewis structure is the combination of 34 valence electron and 5 electron pairs around the Sulfur, where there are 4 bonding pairs and 1 lone pair. This electron arrangement is called ‘Trigonal Bipyramidal’.

The SF₄ molecular shape looks like a see-saw. The reason behind this is that the lone pair prefers one of the equatorial positions. Here, the SF₄ molecular geometry bond angles are around 102° in an equatorial plane and around 173° between the equatorial and axial positions.

Electron pairs’ bonding has fewer repulsions when compared to the electron's lone pair. The advantage of this structure is that it shows the bonding and chemical connectivity of all the particles that are associated with the reactivity and atoms of a molecule. 

It also suggests how it might interact with the other molecules. Sulfur is the least electronegative element in this structure and hence it gets transferred in the middle of the structure, and the diagram provides three-dimensional structural information.

Is SF₄ Polar?

Molecule polarity provides the acknowledgement regarding the molecule’s boiling point, solubility, and more.

To know if the molecule is either polar or nonpolar, observe the sulfur tetrafluoride molecular geometry. It is the easiest way to understand polarity. 

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• If there are a few lone pairs of electrons around the central atom, and the molecule is polar (if there is an odd number). The same goes for the SF₄ molecule. Here, there is only one lone pair around the central atom of the Sulfur, which is an odd number. Therefore, the SF₄ molecule is polar.

• Now, on the other hand, the molecule might be nonpolar with an even number of electrons. But before any final decision, it is suggested to check the VSEPR structure and then decide based on the diagram.

• Otherwise, 2 S-F bonds are opposite from each other, in complete 180°. But the other 2 S-F bonds are pointing down. So, the SF₄  molecule is polar. It is nonpolar If the charge distribution is symmetric.