How to draw SF4 Lewis Structure? - Science Education and Tutorials

Drawing SF4 Lewis Structure is very easy. Here in this post, we described step by step method to construct SF4 Lewis Structure.

Table of Contents

Key Points To Consider When Drawing The SF4 Structure

A three-step approach for drawing the SF4 Lewis structure can be used. The first step is to sketch the Lewis structure of the SF4 molecule, to add valence electron around the sulfur atom; the second step is to valence electron to the four fluorine atoms, and the final step is to combine the step1 and step2 to get the SF4 Lewis Structure.

The SF4 Lewis structure is a diagram that illustrates the number of valence electrons and bond electron pairs in the SF4 molecule. The geometry of the SF4 molecule can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory), which states that molecules will choose the SF4 geometrical shape in which the electrons have from one another.

Finally, you must add their bond polarities to compute the strength of the S-F bond (dipole moment properties of the SF4 molecule). The sulfur-fluorine bonds in sulfur tetrafluoride(SF4), for example, are polarised toward the more electronegative fluorine, and because both bonds have the same size and located around four terminals, their sum is non zero due to the SF4 molecule’s bond dipole moment and the lone pairs of electron on sulfur atom. The SF4 molecule is classified as a polar molecule.

The molecule of sulfur tetrafluoride (with trigonal bipyramidal molecular geometry) is tilted, the bond angles between sulfur and fluorine are 102 and 173 degrees, respectively. It has a difference in electronegativity values between sulfur and fluorine atoms, with sulfur’s pull being less than fluorine’s terminal in the SF4 molecule. As a result, it has the permanent dipole moment. The SF4 molecule has a permanent dipole moment due to an equal charge distribution of negative and positive charges. The net dipole moment of the SF4 molecule is 0.632 D.

SF4 Lewis Structure:

The central atom is sulfur, which is bordered on four terminals with fluorine atoms and one lone pair on the sulfur. Sulfur has six outermost valence electrons, indicating that it possesses six electrons in its outermost shell, whereas fluorine only has seven valence electrons in its outermost shell. To complete the octet of the fluorine atom, a fluorine terminal atom requires one electron. If you’re interested in learning more about the fluorine octet rule, please see in our previous post.

Four fluorine atoms establish covalent connections with the sulfur atom as a result, leaving the sulfur atom with one lone pair. There is one lone pair on the sulfur central atom that resist the bond pairs of the four S-F. According to VSEPR theory, the electronic repulsion of the lone pair and bond pair leads the SF4 molecule to take on a trigonal bipyramidal molecular geometry shape.

The SF4 molecule’s S-F bonds are arranged in asymmetrical order around the bipyramidal molecular geometry, giving rise to the SF4 molecular shape. The SF4 molecule has a bipyramidal molecular geometry because there is electrical repulsion between lone pair and bond pairs of SF4 molecule.

Electronegative Difference Calculation of SF4 Molecule:

The sulfur atom has an electronegativity of 2.58, while fluorine has an electronegativity of 3.98 in the SF4 molecule. The difference in electronegativity can be estimated using the method below.

The electronegative value difference between sulfur and fluorine
Electronegativity value of sulfur = 2.58
Electronegativity value of fluorine= 3.98
Difference of electronegativity value between sulfur and fluorine= 3.98 – 1.57 =1.4
Electronegativity difference between S-F bond calculation of SF4 molecule

Due to the difference in electronegativity value of greater than 0.5, the S-F bond of the SF4 molecule becomes polar. Because of this difference in electronegativity, the SF4 molecule’s S-F bond becomes polar. The electronegativity of an atom is the strength with which it may attract bound electron pairs to its side. The polarity of SF4 is discussed in our previous post.

As a result, the S-F bond’s dipole moment is high due to the polarization of the bonds, and all S-F bonds’ dipoles are arranged in the bipyramidal molecular geometry. The SF4 molecule’s total dipole moment is predicted to be 0.632 D. It has a partial negative charge for fluorine atoms and a partial positive charge for the central sulfur atom.

The electron dot structure of the SF4 molecule is also known as the SF4 Lewis structure. It determines the number of outermost valence electrons as well as the electrons engaged in the SF4 molecule’s bond formation. The outermost valence electrons of the SF4 molecule must be understood while considering the Lewis structure of the molecule.

The sulfur atom is the middle element in SF4 molecular geometry, with six electrons in its outermost valence electron shell, whereas the fluorine atom has seven electrons in its outermost valence electron shell.

The SF4 molecule has a total of 34 valence electrons as a result of the foregoing above said reasoning. With the core central sulfur atom, the four terminal fluorine atoms form covalent bonds, leaving the sulfur atom with one lone pairs on it.

The bipyramidal molecular geometry and structure of the SF4 molecules are similar to that of the ammonia (NH3) molecule. Because one lone pair of a central sulfur atom create interaction with S-F bond pairs. The bond angle of the F-S-F bond in the bipyramidal molecular geometry are approximately 102 and 173 degrees, respectively. The S-F bond lengths are 102 and 165 pm(picometer).

To sketch the SF4 Lewis structure by following these instructions:

Step-1: SF4 Lewis dot Structure by counting valence electron

To calculate the valence electron of each atom in SF4, look for its periodic group from the periodic table. The oxygen and halogen families, which are the 16th and 17th groups in the periodic table, are both made up of sulfur and fluorine atoms. In their outermost shells, sulfur and fluorine have six and seven valence electrons, respectively.

Because sulfur and fluorine are members of the periodic table’s oxygen and halogen family groups, their valence electrons are six and seven, respectively.

Calculate the total number of valence electrons in the SF4 molecule’s outermost valence shell. The first step is to determine how many electrons are in the SF4 Lewis structure’s outermost valence shell. An electron in an atom’s outermost shell is known as a valence electron. It is represented by dots in the SF4 Lewis diagram. The SF4 molecule’s core carbon atom can be represented as follows:

Total outermost valence shell electron of sulfur atom in SF4= 6
Total outermost valence shell electron of the fluorine atom in SF4= 7
The SF4 molecule has one central sulfur atom and four fluorine atoms. Then the total outermost valence shell electrons can be calculated as follows
∴ Total outermost valence shell electrons available for SF4 Lewis structure( dot structure) = 6 +4*7= 34 valence electrons in SF4
calculation of total valence electron of SF4 molecule

Choose the atom with the least electronegative value atom and insert it in the center of the molecular geometry of SF4. We’ll choose the least electronegative value atom in the SF4 molecule to place in the center of the SF4 Lewis structure diagram in this phase. The electronegativity value in periodic groups grows from left to right in the periodic table and drops from top to bottom.

Step-2: Lewis Structure of SF4 for constructing around the more electronegative atom

As a result, sulfur is the second atom in the periodic table’s oxygen family group. Fluorine is the first member of the halogen family. The electronegative value of the sulfur atom is lower than that of the fluorine atom. Furthermore, sulfur has a six electrons limit since fluorine is the most electronegative element in the SF4 molecule.

In the SF4 Lewis structure diagram, the sulfur atom can be the center atom. As a result, central sulfur in the SF4 Lewis structure, with all four fluorine arranged in the bipyramidal trigonal geometry.

Step-3: Lewis dot Structure for SF4 generated from step-1 and step-2

Connect the exterior and core central atom of the SF4 molecule with four single bonds (S-F). In this stage, use four single bonds to connect all four fluorine atoms on the outside of the SF4 molecule to the central sulfur atom in the middle.

Count how many electrons from the outermost valence shell have been used in the SF4 structure so far. Each S-F bond carries two electrons because each sulfur atom is connected to four fluorine atoms by two S-F bonds. Bond pairings of S-F are what they’re called.

So, out of the total of 34 valence electrons available for the SF4 Lewis structure, we used 8 for the SF4 molecule’s four single (S-F) bonds. The SF4 molecule has one lone pair electron in the center of sulfur. We need to put the two extra electrons in the molecular geometry of SF4.

Place the valence electrons in the S-F bond pairs starting with the core sulfur and four fluorine atoms in the SF4 molecule. In the SF4 Lewis structure diagram, we always begin by introducing valence electrons from the central sulfur atom. As a result, wrap around the central sulfur atom’s bond pair valence electrons first.

Sulfur requires 10 electrons in its outermost valence shell to complete the molecular stability, 8 electrons bond pairs in S-F. Then place two electrons as a lone pair of electrons on sulfur of SF4 molecule. Sulfur already shares 8 electrons to the four single bonds(S-F). Then place the valence electron in the fluorine atom, it placed around seven electrons(step-2). Totally, 24 valence electrons placed on the four fluorine atoms of the SF4 molecule.

We’ve positioned 10 electrons around the central sulfur atom(step-3), which is represented by a dot, in the SF4 molecular structure above. The sulfur atom completes its molecular stability in the SF4 molecule because it possesses 8electrons in its bond pairs with four fluorine and one lone pair in the outermost valence shell.

Count how many outermost valence shell electrons have been used so far using the SF4 Lewis structure. Four electrons are shown as dots in the SF4 chemical structure, whereas four single bonds each contain two electrons. The outermost valence shell electrons of the SF4 molecule are 10 + 24= 34 as a result of the calculation.

So far, we’ve used 34 of the SF4 Lewis structure’s total 34 outermost valence shell electrons. One lone pair of electrons on the sulfur atom in the bipyramidal geometry of SF4 molecule.

Complete the middle sulfur atom stability and, if necessary, apply a covalent bond. The central sulfur atom undergoes extra octet stability. Because it has a total of ten electrons in the outermost valence shell.

The core atom in the SF4 Lewis structure is sulfur, which is bonded to the fluorine atoms by four single bonds (S-F). With the help of four single bonds, it already shares eight electrons. As a result, fluorine follows the octet rule and has eight electrons surrounding it on the four terminals of the SF4 molecule’s bipyramidal trigonal geometry.

How to calculate the formal charge on a sulfur atom in SF4 Lewis Structure?

The formal charge on the SF4 molecule’s sulfur central atom often corresponds to the actual charge on that sulfur central atom. In the following computation, the formal charge will be calculated on the central sulfur atom of the SF4 Lewis dot structure.

To calculate the formal charge on the central sulfur atom of the SF4 molecule by using the following formula:
The formal charge on the sulfur atom of SF4 molecule= (V. E(S)– L.E(S) – 1/2(B.E))
V.E (S) = Valence electron in a sulfur atom of SF4 molecule
L.E(S) = Lone pairs of an electron in the sulfur atom of the SF4 molecule.
B.E = Bond pair electron in S atom of SF4molecule
calculation of formal charge on sulfur atom in SF4 molecule

The sulfur core atom (four single bonds connected to fluorine) of the SF4 molecule has six valence electrons, two lone pair of electrons, and eight bonding electrons. Put these values for the sulfur atom in the formula above.

Formal charge on sulfur atom of SF4 molecule = (6- 2-(8/2)) =0

In the Lewis structure of SF4, the formal charge on the central sulfur atom is zero.

Summary:

In this post, we discussed the method to construct the SF4 Lewis structure. Need to remember that, if you follow above said method, you can construct molecular dot structure very easily.