Geometry, Hybridization, and Polarity of CHF3 Lewis Structure

Fluoroform, often known as trifluoromethane, is a colourless, non-flammable gas with the chemical formula CHF3. It belongs to the haloforms class, as the name suggests (class of compounds in which halogen atoms like Fluorine, Chlorine replaces hydrogen atoms of methane).

In 1894, Maurice Meslans, a French pharmacist and chemist, created Fluoroform by reacting iodoform with dry silver fluoride. It is, however, manufactured industrially as a by-product of the reaction of chloroform (CHCl3) and hydrogen fluoride (HF) and as a precursor to the synthesis of compounds such as Teflon.

Fluoroform is a powerful greenhouse gas, yet it does not contribute to the ozone layer’s depletion. It has a wide range of uses, including refrigerants, fire extinguishers, polymer intermediates, and more.

We’ll go through some of the most often asked topics about CHF3, such as its Lewis dot structure, geometry, hybridization, and polarity, in this post.

Name of compoundBeryllium Iodide
Chemical formulaCHF3
Melting point118 K
Boiling point191.1 K
Total number of valence electrons26
Nature of bondCovalent
Molecular geometry of CHF3Tetrahedral
Electron geometry of CHF3Tetrahedral
HybridizationSp3
PolarityPolar

CHF3 Lewis Dot Structure

The valence electrons of atoms in molecules are represented as lone pairs or within bonds in the Lewis dot structure. One central carbon atom, three fluorine atoms, and one hydrogen atom serve as terminal atoms in the Lewis dot structure of CHF3.

How to Draw the Lewis Dot Structure of CHF3 in Steps

Count the total number of valence electrons in CHF3 in step one:

One Carbon atom, one Hydrogen atom, and three Fluorine atoms make up trifluoromethane. Remember the atom’s periodic table group number to find out how many valence electrons it has (up to atomic number 20).

Hydrogen, for example, is in the first group of the Periodic table, hence its valence electron is 1.

Because carbon belongs to the 14th Group of the Periodic Table, it has four valence electrons.

Fluorine belongs to the 17th Group of the Periodic Table, which means it has seven valence electrons.

CHF3 has a total valence electron count of 4 + 1 + 7 (3) = 26.

Step 2: Select the Lewis dot structure’s centre atom:

In Lewis dot structure, the molecule’s least electronegative atom (excluding Hydrogen) can be depicted as a centre atom.

Because electronegativity grows from left to right in the Periodic table, carbon is less electronegative than fluorine in CHF3, thus place carbon as the central atom with one hydrogen and three fluorine atoms as the surrounding atoms.

Step 3: Use a single bond to connect the outside atoms to the core atom:

Draw a skeletal molecule of CHF3 by linking all exterior atoms by a single bond to a centrally located Carbon atom. As a result, this structure has a total of four bonds.

Every single link represents the sharing of two electrons, resulting in a total of 4 2 = 8 valence electrons in this configuration.

There are 18 valence electrons left after subtracting 26 from 8.

Step 4: Complete the octet by arranging the remaining valence electrons:

The octet rule asserts that for an atom to be stable, it must contain eight electrons in its outermost shell.

To complete the octet, start arranging the remaining valence electrons from the outer atom to the central atom.

A single bond already connected two electrons in the hydrogen atom. In this way, the outermost shell of the creature is filled. As a result, there is no need to attach an electron to the Hydrogen atom.

A single link connected each fluorine atom to two electrons. It simply needs 6 extra electrons to complete its octet this way, so wrap 6 electrons around each Fluorine atom.

Four single bonds had previously shared eight electrons between carbon atoms. In this way, the outermost shell of the creature is filled. As a result, there is no need to attach an electron to the Carbon atom.

Step 5: To check for stability, calculate the formal charge on each atom:

The stability of the Lewis dot structure is determined by its formal charge. The lower the formal charge, the more stable the structure.

To compute Formula Charge, use the following formula:

Valence electrons in a neutral atom – lone pair electrons – 1/2 bonded pair electrons = formal charge

Carbon atom formal charge:

Carbon valence electrons = 4

Carbon = 0 lone pair electrons

Around Carbon (shown as a single bond), bonded pair electrons = 8

4 – 0 – 8/2 = 0 formal charge on carbon atom

Hydrogen atom formal charge:

Hydrogen has one valence electron.

Hydrogen lone pair electrons = 0

Around Hydrogen (shown as a single bond), bonded pair electrons = 2

Hydrogen atom formal charge: 1 – 0 – 2/2 = 0.

Each fluorine atom has a formal charge of:

Fluorine has a valence electron of 7

Fluorine lone pair electrons (shown as dots) = 6

Around Fluorine (shown as a single bond), bonded pair electrons = 2

Each fluorine atom has a formal charge of 7 – 6 – 2/2 = 0.

Because all of the atoms in this structure have a formal charge of zero, it is the most stable Lewis dot structure for CHF3.

Geometry of CHF3

The valence electron pair repulsion (VSEPR) model is used to forecast the molecule’s shape. The essential idea is that the shape of a molecule is determined by the repulsion of electron pairs in the valence shells.

To keep the arrangement stable, electrons tend to align themselves in such a way that the distance between them remains greatest and the repulsion between them remains minimal.

Steps for Using VSEPR Theory to Determine the Geometry of CHF3

• Examine the Lewis structure of CHF3 again.

• Count the number of bonding and lone pair electrons in the vicinity of the core atom.

• Calculate the geometry based on the molecular type or VSEPR notation (expressed as ABnEm, where A represents Central atom, Bn represents the number of bonding pairs and Em represents the number of lone pairs).

Note that numerous bonds, such as a double or triple bond, are counted as a single bonding pair.

The core atom in the Lewis structure of CHF3 is carbon, which contains four single bonds (4 electrons) and no lone pairs. As a result, its VSEPR designation is AB4Eo or AB4.

The geometry of CHF3 is tetrahedral with a bond angle of 109.50, according to the VSEPR table below.

The geometries of molecules without a lone pair on the centre atom are shown in Table 1:

The geometries of molecules having one or more lone pairs on the central atom are shown in Table 2.

Hybridization of CHF3

Hybridization is the notion of redistribution of atomic orbital energy to produce a new hybrid orbital in chemistry.

The following are some of the most important characteristics of hybridization:

• In hybridization, atomic orbitals with equal energies participate.

• The number of hybrid orbitals created is the same as the number of atomic orbitals involved.

• Hybridization occurs only when the link is formed.

• It can be classified as sp, sp2, sp3, sp3d, or sp3d2 depending on the number of atomic orbitals involved.

The number of orbitals that are involved can be computed as follows:

• 12 (number of monovalent atoms linked to the centre atom + valence electrons in a neutral central atom)

OR

• Number of central atom sigma bonds + lone pairs on the central atom

Number of included orbitalsHybridization
2Sp
3Sp2
4Sp3
5Sp3d

Hybridization number of orbitals included

CHF3 hybridization

The number of monovalent atoms connected to the core atom in CHF3 is equal to four.

A neutral centre atom has four valence electrons.

The number of participating orbitals is 12 (4 + 4) = 4 = sp3 according to the formula above. Hybridization

In other terms, it is equivalent to the atomic number of carbon: 6.

1s2 2s2 2px2 2py02pz0 electronic setup

What is the ground state electron configuration of a neutral carbon atom, and what is the ground state electron configuration of a carbon atom in an excited state? | Socratic method

When carbon is stimulated, one of its electrons travels from the 2s orbital to the 2p orbital (2s and 2p have similar energy levels). It’s four sp3 hybrid orbitals made up of one s and three p orbitals.

Hydrogen has an atomic number of one.

1s1 is the electronic configuration of hydrogen.

Fluorine has an atomic number of 9.

Fluorine Electronic Configuration = 1s2 2s2 2px22py22pz1

In their 1s and 2p orbitals, hydrogen and fluorine each have one unpaired electron, and these unpaired electrons form a bond with each sp3 hybridised orbital.

Polarity of CHF3

Because fluorine is more electronegative than carbon, it attracts the electron in the C-F bond. Despite the fact that Carbon is more electronegative than Hydrogen, the former pulls electrons towards itself in the C-H bond.

Fluorine acts as the negative end of the molecule because it is the most electronegative, whereas hydrogen acts as the positive end of the molecule because it is the most electropositive. As a result, CHF3 possesses a dipole moment that is not zero. The molecule CHF3 is polar.

CHF3 Polarity is Determined by

Electronegativity

When the difference in electronegativity between atoms grows, polarity grows. Fluorine has an electronegativity of 3.98 in CHF3, while carbon has an electronegativity of 2.6.

The asymmetric distribution of charges around the atom is caused by the difference in electronegativity between Fluorine and Carbon.

The molecule’s geometry or shape

The majority of asymmetric formations are polar in nature. Because CHF3 has a tetrahedral geometry and is asymmetric, it is classified as polar.

Conclusion

CHF3 is the chemical formula for fluoroform, a haloform. Although it is a powerful greenhouse gas, it does not contribute to ozone depletion.

CHF3 has 26 valence electrons, 18 of which are lone pair electrons and 8 of which are bond pair electrons.

CHF3 has four bond pairs and zero lone pairs, hence it has tetrahedral geometry with a bond angle of 109.5 degrees, according to VSEPR theory.

CHF3 sp3 hybridization occurs when one s and three p orbitals combine to generate four sp3 hybrid orbitals.

Because of the disparity in electronegativity of the atoms and the asymmetrical structure, CHF3 is a polar molecule. CHF3 has a dipole moment of 1.8 D.

Good luck with your reading!!

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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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