Hybridisation of SF₆

JEE Crash Course 2022

Hybridization

Hybridisation occurs when two or more atomic orbitals from the same atom are mathematically merged to generate a new orbital that is unique from its constituent parts.

It is just an intermixing of unlike orbitals with similar energy to make new hybrid orbitals.

Hybridization was proposed as the best explanation for why all C - H bonds in methane molecules were identical.

Determination of Hybridization State 

The following are simple ways for determining whether or not hybridization occurred:

  1. You can learn more about the atom by observing it.

  2. Rather than counting the number of bonds between atoms, count the number of atoms linked.

  3. Count how many lone pairs are attached.

  4. Add the atoms and lone pairs to get the final number.

  • Sum 4 = Atom sp3

  • Sum 3 = Atom sp2

  • Sum 2 = Atom sp

Besides the above ways, there is another way to determine the hybridization state. The second method, however, may not always be accurate.

It is through a formula: 0.5(V+M-C+A)

V  =  The total number of valence electrons in a central atom

M =  No. of monovalent atom

C  = Total Cation charge

A  = Total Anion charge

SF6 (Sulphur Hexafluoride) - Characteristics, Hybridization and Geometry

Sulphur hexafluoride is a non-toxic, non-flammable greenhouse gas that is colorless and odorless. It is inorganic and non-polar. SF6 is normally made by exposing or combining S8 with F2

Characteristics of SF6

  • Chemically, SF6 gas is extremely stable.

  • It's non-flammable and highly electronegative, with a dielectric property that's around 2.5 times that of air.

  • Used as electrical insulation, arc quenching and cooling medium in switchgear, transformers and substations.

  • It's soluble in nonpolar organic solvents but not in water.

  • In the air, sulphur hexafluoride is a dense gas that tends to stay low.

Hybridization and Geometry of SF6

SF6 hybridization is sp3d2. Let’s see how?

The orbitals involved in sulphur hexafluoride hybridization, as well as the bonds created during the interaction of sulphur and fluorine molecules, determine hybridization.

In its ground state, SF6 has the electrical configuration 3s23p4. However, when it shares electrons and is excited, the electron pairs in both the 3s and 3p orbitals become unpaired.

These electrons travel upward to fill the higher 3d orbitals that are empty. Six hybrid orbitals are then created:

  • one of 3s

  • three of 3p

  • two 3d

All the above six half-filled orbitals get hybridized now. This results in the production of six sp3d2 hybrid orbitals. The sp3d2 hybrid orbitals also overlap with a 2p fluorine orbital, forming the S-F bond.

Geometry of SF6

With Sulphur Hexafluoride, the core element is Sulphur and the fluorine atoms are symmetrically distributed around it. The atoms are arranged in an octahedral arrangement, which results in the octahedral molecular geometry of SF6.

Name of the Molecule  : Sulphur Hexafluoride

Molecular Formula        : SF6

Hybridization Type        : sp3d2

Bond Angle                     : 90o

Geometry                        : Octahedral

FAQs (Frequently Asked Questions)

1. What are the Characteristics of SF6 Gas?

SF6 is colorless, odorless, nonflammable, and nontoxic. It is virtually inert, which means it is stable and does not react with other chemicals under normal conditions.

2. Is SF6 Gas Harmful to the Environment?

This gas does not deplete the ozone layer or cause air pollution. It is, however, almost 24,000 times more effective than carbon dioxide (CO2) at trapping heat, making SF6 potent greenhouse gas. That is why it is so important to always monitor the SF6 level in electrical switch gears for leaks.

3. Write a Few Features of Hybridization?

Few features of hybridization are as follows.

1. Hybridization is a mixing of orbitals and not electrons. Therefore in hybridization full filled, half-filled and empty orbitals may take part.

2. The number of hybrid orbitals formed is always equivalent to the number of atomic orbitals that may take part in the process of hybridization. 

3. Each hybrid orbital has two lobes, one is longer and the other is smaller. The bond will be formed from a large lobe. 

4. The number of hybrid orbitals on the central atom of a molecule or ion = number of sigma bonds + lone pair of electrons.

 

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4. What are the important characteristics and types of Hybridization?

The number of initial intermixing orbitals equals the number of hybrid orbitals generated.

  • The pure property is not present in hybrid orbitals.

  • The hybrid orbitals are similar in shape and energy 

  • Hybridization can occur in both half-filled and fully-filled orbitals.

  • The energy levels of the orbitals involved in hybridization must be the same or similar.

Types of Hybridization

Hybridizations vary in nature and the number of participating atomic orbitals. Below are its types:

  1. sp hybridization

  2. sp2 hybridization

  3. sp3 hybridization

  4. sp3d hybridization

  5. sp3d2 hybridization

  6. sp3d3 hybridization

5. What is the purpose of hybridization?

In 1931, scientist Pauling established the breakthrough notion of hybridization. He emphasizes that the most stable structure is achieved by hybridization.

There are enough electrons to complete the necessary bonds when there exist hybrid orbitals, regardless of whether there are enough valence electrons.

Carbon, for example, has only two valence electrons, but due to hybridization, there are four electron regions available for bonding, allowing carbon to form its most stable bonds.

6. What are the five basic shapes of Hybridization?

The five basic shapes of hybridization are:

  1. Linear: The involvement of two-electron groups results in sp hybridization; the angle between the orbitals is 180°.

  2. Trigonal Planar: Three electron groups are involved, resulting in sp2 hybridization; the orbital angle is 120°.

  3. Tetrahedral: The involvement of four electron groups results in sp3 hybridization; the angle between the orbitals is 109.5°.

  4. Trigonal Bipyramidal: Five electron groups are involved, resulting in sp3d hybridization; the orbital angles are 90° and 120°.

  5. Octahedral: The involvement of six electron groups results in sp3d2 hybridization; the orbitals are 90° apart.

7. What makes SF6 gas such a good dielectric medium?

Dielectricity refers to the ability to carry electricity without the presence of conductivity.  Dielectric strength relates to how well something can endure high voltage without becoming damaged.

The ability to acquire free electrons is referred to as electronegativity, and fluorine is the most electronegative element known to exist. SF6 is composed of six fluorine molecules that can break away from the sulphur atoms. It catches electrons during an arc, and then reverts to their original states. 

Its strong dielectric strength and electronegativity make it a common insulating gas for power T&D equipment.

8. What are the hazards of SF6?

Despite its importance in power plant efficiency, SF6 poses substantial gas hazards listed below.

Global warming. When compared to other known gasses, SF6 has the highest Global Warming Potential (GWP).

Equipment failure. A gas leak could cause equipment failure due to malfunctioning, for example. This, in turn, will raise the cost, which could be costly in terms of both time and money.

Health risk. SF6 is heavier than air and can settle in low-lying areas, creating respiratory difficulties among employees.

Note: Students can go to Vedantu's website for further information about SF6 Hybridization.

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