Geometry, Hybridization, and Polarity of SeF6 Lewis Structure

Selenium hexafluoride is an inorganic compound made up of two atoms of Selenium and six atoms of fluorine.

It’s a colourless, corrosive, and deadly gas with a distinct odour.

We’ll go through the fundamentals of drawing Lewis structures and predicting geometry, hybridization, and polarity for a given chemical in this post.

Structure of Lewis

The arrangement of valence shell electrons around each atom in a molecule is represented by the Lewis structure, which is a structural formula.

It’s crucial for estimating how many and what kind of bonds an atom will make.

Electrons are represented by dots, while bonds are depicted by lines surrounding the chemical symbol of an element in a Lewis structure. A bond is formed when two dots on adjacent atoms are linked together.

Lewis dot structures can exist in more than one form in some chemicals. The one that satisfies the octet rule and has the fewest formal charges is the most stable in such instances.

The Rule of the Octet

Because main group elements are considered inert, they want to have an electrical configuration comparable to noble gases.

All other main group elements lose or gain electrons to attain this configuration. Noble gases have 8 valence electrons (except He), while all other main group elements lose or gain electrons to achieve this configuration.

The octet rule refers to the preference for having 8 electrons in the valence shell of main group elements.

It is one of the most basic ideas. Although many compounds are stable, they do not adhere to the octet rule. The following are exceptions to the octet rule:

• Because the sum of electrons is always odd, odd electron species can never complete their octet. For instance, NO, NO2, and so on.

• Hypovalent Species – Some species with less than 8 electrons in their valence shell are still stable. For instance, B in BH3, Al in AlCl3, and so on.

• Hypervalent Species – Some species can have more than 8 electrons in their valence shell and still be stable. Atoms having more than two shells can increase the size of their octet by adding unoccupied d orbitals. For instance, S in SF6, and so on.

Charge Formal

It establishes a direct link between the number of electrons present on an isolated neutral atom and the number of electrons present on that atom when it is combined.

Charge in formal terms= (number of electrons in an isolated neutral atom)

– (number of nonbonding electrons on an atom in the compound)

-0.5 * (number of electrons shared in bonds by atom)

To get the lowest formal charge, as many atoms as feasible must have a zero formal charge.

If a formal charge is present, the more electronegative elements should have a negative formal charge, whereas the less electronegative elements should have a positive formal charge.

How to Draw the SeF6 Lewis Structure in Steps

Step 1: Count the total number of electrons in the valence shell of the chemical.

We need to know the total amount of valence shell electrons on all constituent atoms before we can design the structure.

Se and F Valence Electrons

Step 2: For elements, draw the Lewis dot structure.

The Lewis structure of an element is drawn by arranging the valence shell electrons around the chemical symbol of the element.

Selenium and fluorine have the chemical symbols Se and F, respectively. For Se and F, the Lewis dot structure is as follows:

Step 3: Pick a good core atom for your chemical.

Because the centre atom is expected to share its electron density with the other atoms, it should be the least electronegative of the constituent atoms.

As a result, Se is the compound’s core atom.

Step 4: Sketch down a skeleton diagram.

We must now properly arrange the side atoms and core atom in this stage.

Arrange the valence electrons around the elemental symbols in step 5.

The total valence shell electrons (estimated in step 1) are arranged around chemical element symbols. The orange dots indicate selenium electrons, while the black dots represent fluorine electrons.

Step 6: Form bonds to complete the octet of atoms.

With the core atom, all side atoms create a single bond.

In the solitary state, each F contains seven valence electrons. To have a fully filled valence shell structure, they share one electron with Se.

In its isolated state, Se possesses six valence electrons. It has one electron in common with all F-atoms.

The centre atom is surrounded by 12 electrons. Because Se can expand its octet due to unoccupied d orbitals and make more than four bonds, SeF6 is a hypervalent molecule.

Step 7: Determine all atoms’ formal charges.

This chemical has a net charge of zero. As a result, the total formal charge on seven atoms should equal zero.

As a result, the Lewis structure generated in step 6 is the best for SeF6.

This link can help you better comprehend the process of drawing a Lewis structure.

Geometry of SeF6

The 3D arrangement of atoms in a compound is known as molecular geometry. Exact geometry can only be discovered by laboratory experimentation.

We may, however, utilise VSEPR theory to predict the form without having to experiment. The valence electron pair repulsion theory is abbreviated as VSEPR.

The VSEPR theory states that

Instability is caused by the valence electron pairs repelling one other.

The repulsions between the electrons must be reduced to make the arrangement of the electrons stable.

As a result, electrons arrange themselves with the least amount of repulsion and the greatest distance between them.

The molecular geometry is determined by the stable arrangement of atoms’ valence electron pairs.

Bonding pairs of electrons (bp) are valence shell electrons that are involved in bonding, while lone pairs of electrons are valence shell electrons that are not involved in bonding (lp).

How to Use VSEPR to Predict SeF6 Geometry

Step 1: Calculate A by counting the number of valence shell electrons on the centre atom (arbitrary variable)

Se is the core atom in the SeF6 formula. Se has a valence electron count of six. (Shown in step 1 of the Lewis structure drawing)

A=6

Step 2: Determine the number of side atoms and multiply by B. (arbitrary variable).

There are six side atoms (fluorine) in SeF6, and B=6.

Step 3: Subtract the charge from B for positively charged compounds and add the charge to B for negatively charged compounds if the chemical is charged. For neutral substances, this step might be skipped.

There is no charge contribution in SeF6, and B=6 is the only value.

Step 4: Add the contributions of side atoms and charge to the core atom’s contribution, i.e. A+B.

A+B=12 for SeF6.

Step 5: Multiply A+B by 2 to get the total number of electron pairs that affect the form.

There are six electron pairs in SeF6.

Step 6: Separate the total electron pairs into bonding and non-bonding electron pairs. The number of side atoms equals the number of bonding electron pairs.

There are six side atoms in SeF6. As a result, there are six electron bonding pairs and zero nonbonding pairs.

The following table can be used to forecast geometry and shape based on this information.

Step 7: The geometry and form of electrons are octahedral. Compounds with zero lone pairs have the same geometry and form.

SF6 is a chemical that is extremely similar to SF6. SF6 Lewis Structure, Geometry, Hybridization, and Polarity are all readout.

Hybridization of SeF6

One of the most basic ideas used to describe bond formation is hybridization. It was first mentioned by Linus Pauling.

Hybridization is the process of combining two or more atomic orbitals to create orbitals that are identical in energy, shape, and size. The level of overlap between hybridised orbitals and unhybridized orbitals is better.

It does not include mixing in the traditional sense. The only thing that happens is that wavefunctions are mixed.

One 4s and one 4p, for example, can combine to generate two sp hybrid orbitals, whereas 1s and 5p cannot.

Se is the core atom in SeF6. We’re just interested in the core atom’s hybridization.

Se possesses two unpaired electrons in its ground state. It can only make two bonds at a time.

Electrons are promoted, and all six valence electrons become unpaired.

These six electrons can be found in a variety of orbitals. To generate sp3d2 hybrid orbitals, all six orbitals are hybridised.

The formula for determining the kind of SeF6 hybridization

In the last step of VSEPR theory, we estimated the total electron pairs.

It came out to be 6 for SeF6.

Using total electron pairs or steric numbers, the table below can predict hybridization.

The number of (sigma bonds + a lone pair on the central atom) sterics is equal to the number of (sigma bonds + a lone pair on the central

SeF6 has a steric number of (6+0)=6.

The chart shows that hybridization is sp3d2.

Polarity of SeF6

The existence or absence of a compound’s net dipole moment determines the compound’s polarity.

The net dipole moment is influenced by

The bond’s dipole moment

The difference in electronegativity between atoms

Geometry

Only one type of bond is present in SeF6, namely the Se-F bond. Se and F have electronegativity of 2.55 and 3.98, respectively. The difference is equal to 1.43. The bonds are polar, with a non-zero bond dipole moment.

A polar compound does not have to have polar bonds. A vector quantity is the dipole moment. The dipole moment is cancelled when the form is symmetrical.

SeF6 has an octahedral form. All dipole moments cancel out, resulting in a net dipole moment of zero. As a result, the chemical is a non-polar one.

Conclusion

A hypervalent chemical is SeF6.

The most stable structure is the Lewis structure depicted in the preceding section.

Selenium hexafluoride has an octahedral form and geometry.

SeF6 hybridization is sp3d2.

It’s a non-polar substance.

Good luck with your reading!

Read more: Is NaOH a base or an acid? — Are you a strong or weak person? 

Misha Khatri
Misha Khatri is an emeritus professor in the University of Notre Dame's Department of Chemistry and Biochemistry. He graduated from Northern Illinois University with a BSc in Chemistry and Mathematics and a PhD in Physical Analytical Chemistry from the University of Utah.

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