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 form 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.
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During SF4 formation, the sulfur atom will produce bonds with each of fluorine atoms where 8 of valence electrons are used. Besides, the 4 fluorine atoms will have 3 lone pairs of electrons in its 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.
Before going to understand the molecular geometry of SF4, let us understand What Molecular Formula is.
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 fragment 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:
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.
Lewis Structure is a diagrammatical representation that shows the atoms’ bonding represented by the chemical symbols and the electrons’ lone pairs in some specific molecule. It is linked by the lines i.e., 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 repulsion when compared to the electrons 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.
Molecule polarity provides the acknowledgement regarding the molecule’s boiling point, solubility, and more.
Is SF4 Polar?
To know the molecule is either polar or nonpolar, we should draw the Lewis structure of the molecule. We can also 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). 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 the even number of some lone electrons. But prior to 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, and because of that, their bond dipoles do not cancel. So, the SF4 molecule is polar. It is nonpolar If the charge distribution is symmetric.
1. What is the SF4 Hybridization of the Central Atom?
A. As we are aware that the sulfur molecule is a member of the oxygen family (Group - 16 - P block elements). So, it has 6 valence electrons present in it.
Atomic number of S is 16, and the electronic configuration is: 1s2 , 2s2 , 2p6 , 3s2 , 3p4.
Therefore, this can be calculated according to VSEPR theory, using the formula,
½ [valence electron of central atom + Number of the monovalent atom (H/x)+ Negative Charge - positive charge].
= ½ [6+4]
Thus, the S atom is bonded to 4 fluorine atom and has 1 lone pair. And, there are 5 orbitals.
2. Why does the S atom in SF4 have sp3d hybridization, but not p3d?
A. The S atom in the SF4 is bonded to 4 Fluorine atoms and has 1 lone pair (S has 6 valence electrons; 4 of them undergo bonding with 4 Fluorine atoms while the other 2 remains as a lone pair on S atom). All of them are in the hybridized orbitals. And, there are 5 such orbitals. Due to this, the hybridization is sp3d. This SF4 molecular shape is a see-saw, because of the presence of 1 lone pair.
It is also to make a note that S orbitals also participate in hybridization. 1 S orbital, 3 p orbitals, and 1 d orbital hybridize to form 5 sp3d hybrid orbits. In 4 of these orbitals, there exist the bond pair electrons. In the 5th orbital, a lone pair of electrons reside.