How to draw SiF4 Lewis Structure? - Science Education and Tutorials

Drawing SiF4 Lewis Structure is very easy. Here in this post, we described step by step method to construct SiF4 Lewis Structure.

Table of Contents

Key Points To Consider When drawing The SiF4 Lewis Structure

A three-step approach for drawing the SiF4 Lewis Structure can be used. The first step is to sketch the Lewis structure of the SiF4 molecule, to add valence electron around the silicon atom; the second step is to valence electron to the fluorine atom, and the final step is to combine the step1 and step2 to get the CCl4 Lewis Structure.

The SiF4 Lewis structure is a diagram that illustrates the number of valence electrons and bond electron pairs in the SiF4 molecule. The geometry of the SiF4 molecule can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory), which states that molecules will choose a SiF4 geometrical shape in which the electrons have from one another.

Finally, you must add their bond polarities to compute the strength of the Si-F bond (dipole moment properties of the CFl4 molecule). The silicon-fluorine bonds in silicon tetrafluoride(SiF4), for example, are polarised toward the more electronegative silicon, and because both bonds have the same size, their sum is zero due to the SiF4 molecule’s bond dipole moment, and the SiF4 molecule is classified as a nonpolar molecule.

The molecule of silicon tetrafluoride (with tetrahedral geometry) is tilted at 109 degrees and has a difference in electronegativity values between fluorine and silicon atoms, with fluorine’s pull being roughly equal to silicon’s. As a result, it has no dipole moment indefinitely. The SiF4 molecule has no dipole moment due to an equal charge distribution of negative and positive charges.

How to draw the SiF4 Lewis Structure:

The centre atom is silicon, which is bordered on all sides by four fluorine atoms. Silicon has four outermost valence electrons, indicating that it possesses four electrons in its outermost shell, whereas fluorine has seven. To complete the octet of the silicon atom, a silicon core atom requires four electrons. If you’re interested in learning more about the silicon octet rule, please see our previous post.

Four fluorine atoms establish covalent connections with the silicon atom as a result, leaving the silicon atom without any lone pairs. There are no lone pairs on the silicon core atom that resist the bond pairs of the four Si-F. According to VSEPR theory, no electronic repulsion leads the SiF4 molecule to take on a tetrahedral shape like CH3Cl, CH3F, or CH2Cl2.

The SiF4 molecule’s Si-F bonds are arranged in a symmetrical order around the tetrahedral geometry, giving rise to the tetrahedral shape. The SiF4 molecule has a tetrahedral geometry because there is no electrical repulsion between them.

Electronegative difference calculation SiF4 molecule:

Silicon has an electronegativity of 1.9, while fluorine has an electronegativity of 3.98 in the SiF4 molecule. The difference in electronegativity can be estimated using the method below.

The electronegative value difference between silicon and fluorine
Electronegativity value of fluorine= 3.98
Electronegativity value of silicon= 1.9
Difference of electronegativity value between fluorine and silicon= 3.98 – 1.9=2.08
Electronegativity difference between Si-F bond calculation of SiF4 molecule

Due to the difference in electronegativity value of greater than 0.5, the Si-F bond of the SiF4 molecule becomes polar. Because of this difference in electronegativity, the SiF4 molecule’s Si-F bond becomes polar. But it cancels each other in the tetrahedral geometry. The electronegativity of an atom is the strength with which it may attract bound electron pairs to its side.

As a result, the Si-F bond’s dipole moment is virtually negligible, and all Si-F bonds’ dipoles are centered around the tetrahedral geometry. The SiF4 molecule’s total dipole moment is predicted to be 0 D. It has a partial negative charge for silicon atoms and a partial positive charge for fluorine atoms.

The electron dot structure of the SiF4 molecule is also known as the SiF4 Lewis Structure. It determines the number of outermost valence electrons as well as the electrons engaged in the SiF4 molecule’s bond formation. The outermost valence electrons of the SiF4 molecule must be understood while considering the Lewis structure of the molecule.

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

The SiF4 molecule has a total of 32 valence electrons as a result of the foregoing reasoning. With the core silicon atom, the four fluorine atoms form covalent bonds, leaving the silicon atom with no lone pairs on it.

The tetrahedral geometry and structure of the molecules are similar to that of the chloroform (CH3Cl) molecule because no lone pairs of central silicon atoms create interaction with Si-F bond pairs. The bond angle of the F-Si-F bond is approximately 109 degrees. The Si-F bond has a 108-minute bond length (picometer).

To sketch the SiF4 Lewis structure by following these instructions:

Step-1: Adding valence electron on the silicon atom

Calculate the total number of electrons in the SiF4 molecule’s outermost valence shell. The first step is to determine how many electrons are in the SiF4 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 SiF4 Lewis Structure diagram. The SiF4 molecule’s core silicon atom can be represented as follows:

To calculate the valence electron of each atom in SiF4, look for its periodic group. The silicon and fluorine families, which are the first and 14th groups in the periodic table, are both made up of silicon and fluorine atoms. In their outermost shells, silicon and fluorine have four and seven valence electrons, respectively.

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

Total outermost valence shell electron of silicon atom in SiF4= 4
Total outermost valence shell electron of fluorine atom in SiF4= 1
The SiF4 molecule has one central silicon atom and four fluorine atoms. Then the total outermost valence shell electrons can be calculated as follows
∴ Total outermost valence shell electrons available for SiF4 Lewis Structure( dot structure) = 4 +4*7= 32 valence electrons in SiF4
calculation of total valence electron of SiF4 molecule

Choose the atom with the least electronegative charge and insert it in the molecular geometry of SiF4. We’ll choose the least electronegative atom in the SiF4 molecule to place in the centre of the SiF4 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: Adding valence electron on fluorine atom in the SiF4 molecule

As a result, fluorine is the first atom in the periodic table’s halogen family group. Silicon is the second member of the silicon family. The electronegative value of a fluorine atom is lower than that of a silicon atom. Furthermore, fluorine has a one-electron limit since silicon is the most electronegative element in the SiF4 molecule.

In a SiF4 Lewis Structure diagram, the silicon atom can be the centre atom. As a result, central silicon in the SiF4 Lewis Structure, with all four fluorines arranged around the tetrahedral geometry.

Step-3: Combining step1 and step2 to get step3 for SiF4 dot structure

Connect the exterior and core atoms of the SiF4 molecule with four single bonds (Si-F). In this stage, use four single bonds to connect all four fluorine atoms on the outside of the SiF4 molecule to the central silicon atom in the middle.

Count how many electrons from the outermost valence shell have been used in the SiF4 structure so far. Each Si-F bond carries two electrons because each silicon atom is connected to four fluorine atoms by four Si-F bonds. Bond pairings are what they’re called.

So, out of the total of 32 valence electrons available for the SiF4 Lewis Structure, we used 8 for the SiF4 molecule’s four single (Si-F) bonds. The SiF4 molecule has lost all of its valence electrons. We don’t need to put the extra electron in the molecular geometry of SiF4.

Place the valence electrons in the Si-F bond pairs starting with the core silicon and three fluorine atoms in the SiF4 molecule. In the SiF4 Lewis Structure diagram, we always begin by introducing valence electrons from the central silicon atom. As a result, wrap around the central silicon atom’s bond pair valence electrons first.

Silicon requires 8 electrons in its outermost valence shell to complete its octet. Silicon already shares eight electrons thanks to the four single bonds.

We’ve positioned eight electrons around the central silicon atom, which is represented by a dot, in the SiF4 molecular structure above. The silicon atom completes its octet stability in the SiF4 molecule because it possesses 8 electrons in its outermost valence shell.

Count how many outermost valence shell electrons have been used so far using the SiF4 Lewis Structure. Eight electrons are shown as dots in the SiF4 chemical structure, whereas four single bonds each contain two electrons. The outermost valence shell electrons of the SiF4 molecule are 4 + 4= 8 as a result of the calculation.

So far, we’ve used eight of the SiF4 Lewis structure’s total eight outermost valence shell electrons.

Complete the middle silicon atom octet and, if necessary, apply a covalent bond. The core atom in the SiF4 Lewis Structure is silicon, which is bonded to the fluorine atoms by four single bonds (Si-F). With the help of four single bonds, it already shares eight electrons. As a result, silicon follows the octet rule and has eight electrons surrounding it.

How to calculate the formal charge on the silicon atom in SiF4 Lewis Structure?

The formal charge on the SiF4 molecule’s silicon central atom often corresponds to the actual charge on that silicon central atom. In the following computation, the formal charge will be calculated on the central silicon atom of the SiF4 Lewis dot structure.

To calculate the formal charge on the central silicon atom of SiF4 molecule by using the following formula:
The formal charge on the silicon atom of SiF4 molecule= (V. E(Si)– L.E(Si) – 1/2(B.E))
V.E (Si) = Valence electron in silicon atom of SiF4 molecule
L.E(Si) = Lone pairs of an electron in the silicon atom of the SiF4 molecule.
B.E = Bond pair electron in Si atom of SiF4 molecule
calculation of formal charge on silicon atom in SiF4 molecule

The silicon core atom (four single bonds connected to fluorines) of the SiF4 molecule has four valence electrons, zero lone pair electrons, and eight bonding electrons. Put these values for the silicon atom in the formula above.

Formal charge on silicon atom of SiF4 molecule = (4- 0-(8/2)) =0

In the Lewis structure of SiF4, the formal charge on the central silicon atom is zero.

Summary:

In this post, we discussed the method to construct SiF4 Lewis Structure. Need to remember that, if you follow the above-said method, you can construct molecular dot structure very easily.