Strong or Weak Intermolecular Forces in CCl4

Carbon tetrachloride (CCl4), often known as tetrachloromethane, is a colourless, thick, volatile, very poisonous, and non-flammable liquid. It belongs to the organic halogen chemical family and has a unique odour. It’s a non-polar tetrahedral molecule made up of three Cl-C-Cl bonds with a bond angle of 109.5°.

In 1839, CCl4 was created by reacting chloroform with chlorine for the first time. Carbon tetrachloride is produced commercially by reacting chlorine with methane or carbon disulfide. CCl4 has a boiling point of 77°C and a freezing point of -23°C. CCl4 is not soluble in water because its density is higher than that of water.

We’ll talk about the intermolecular forces that exist within a CCl4 molecule in this post.

In CCl4, what are the intermolecular forces? The only intermolecular forces that keep CCl4 molecules together are London dispersion forces. Despite the fact that the C-Cl bonds are polar, a CCl4 molecule has no dipole-dipole moment. The CCl4 molecule’s geometry is symmetrical, i.e. tetrahedral, and the dipole bonds cancel each other out because their strengths are equal and opposite.

The equal and opposite forces of the two dipole bonds of C-Cl in front and behind the surface cancel each other out. In a CCl4 molecule, only the London dispersion forces exist.

Let’s take a closer look at CCl4’s intermolecular forces.

What are Intermolecular Attraction Forces?

The type of forces that enhance the interaction between molecules are intermolecular forces of attraction, also known as secondary forces.

These forces act between atoms or other particles in a molecule, such as ions. In comparison to intramolecular forces, intermolecular forces are weaker. Intramolecular forces, such as covalent bonds, are what hold a molecule together.

CCl4 Molecule Intermolecular Forces

In a CCl4 molecule, the dipole bonds are balanced out, as we mentioned earlier.

As a result, the London dispersion force, a subunit of the van der Waals force, is the only intermolecular force that prevails. These are the weakest forces, and they only affect the molecule for a short time.

When two atoms are close enough together for their electrons to occupy specific positions. The atoms create a transient dipole as a result of this, and London dispersion forces are induced within the molecule.

Fluctuating dipole-induced dipole attraction is another name for these forces.

London dispersion forces cause non-polar molecules to condense into liquids from gases and freeze into solids from liquids at low temperatures.

Because electrons are always moving, their distribution around the nucleus is unequal. An atom or the entire molecule forms a transient dipole as a result of this.

When a second atom or molecule approaches the induced one, an electrostatic force is created, causing the two atoms or molecules to attract.

Dispersion Forces in London: Factors Affecting Their Strength

The impact and long-term viability of London dispersion forces are dependent on two key elements. The following are the details:

Molecule Dimensions

Both polar and non-polar molecules have London dispersion forces. However, the strength of these forces is related to the atom’s or molecule’s size and weight.

As a result, the London dispersion forces of larger and heavier atoms or molecules are stronger than those of smaller ones.

This is because the valence electrons in the outermost shell of a big molecule are farther away from the nucleus than in a smaller one. They’re weakly bonded and can be quickly released to produce a dipole.

Polarizability

In polarised molecules, the London dispersion forces are stronger. The electron distribution around an atom in polarised molecules can easily be altered.

The Molecule’s Structure

The strength of London dispersion forces is also influenced by the molecule’s shape and structure.

Neopentane (C5H12) is a gas at ambient temperature, whereas n-pentane (C5H12) is a liquid. This is because, while having the same molecular weight, the London dispersion forces inside the n-pentane molecule are stronger than those within the neopentane molecule.

Because of its cylindrical shape, n-atoms pentane’s can come into touch with one another and generate transient dipoles. The spherical shape of neopentane, on the other hand, prevents this development.

The Importance of Intermolecular Attraction Forces

Intermolecular forces of attraction are important because they affect a molecule’s biological, physical, and chemical properties.

Intermolecular forces of attraction effect a molecule’s reactivity, melting temperature, boiling point, freezing point, and solubility.

More energy will be required to separate the molecules as the strength of intermolecular interactions grows.

When a result, as the intermolecular forces of attraction grow, the boiling and melting points of the molecule increase.

Low vapour pressure, increased surface tension, and higher viscosity are all characteristics of molecules with a strong intermolecular force of attraction.

CCl4-based bonding

There are four covalent bonds in a CCl4 molecule. There are four carbon atoms and one chlorine atom in this compound. Through electron sharing, each of these atoms completes its octet.

Furthermore, the electronegativity of carbon and chlorine atoms is rather low, with carbon having a value of 2.5 and chlorine having a value of 3.0.

Bonding occurs in a carbon tetrachloride molecule due to hybridization.

Hybridization is the process of combining two atomic orbitals to produce a new hybridised orbital. The size and shape of this freshly created orbital will be different from that of its preceding orbitals.

The core atom in a CCl4 molecule is carbon. It has a 1s2, 2s2, 2p2 electrical arrangement.

As you can see, there are two unpaired electrons available. The electrical configuration of carbon is changed to 1s2, 2s1, 2p3 when an electron from the 2s orbital jumps into the 2p orbital.

This change allows us to obtain four unpaired electrons. Four sp3 hybridised orbitals are formed when the 2s and 2p orbitals join.

Chlorine has the electrical configuration 1s2, 2s2, 2p6, 3s2, 3p5. To achieve a stable state, only one atom is required. There are four chlorine atoms in our body.

Each chlorine atom forms a one-sigma connection with the centre carbon atom. With sp3 hybridization of each bond, we have four sigma bonds.

The molecule CCl4 is tetrahedral.

CCl4: Is it a Solid or a Liquid?

CCl4 is a liquid at room temperature. It, on the other hand, evaporates quickly and creates gas.

CCl4 has a nice odour, is non-flammable, and only dissolves slowly in water.

Is CCl4 a polar or non-polar substance?

A molecule’s polarity is determined by the presence of a net dipole moment.

We only see C-Cl bonding in a CCl4 molecule. Carbon has an electronegativity of 2.5, while chlorine has an electronegativity of 3.0. As a result, the difference in electronegativity between them is only 0.5, which is negligible.

C-Cl bonds, on the other hand, are still regarded mildly polar. All four C-Cl bonds have the same vector sum of dipole moments, which is zero.

Because carbon tetrachloride is a symmetric chemical, it is a non-polar molecule.

CCl4 or CH4: which has a stronger intermolecular force?

The entire number of electrons in a CCl4 molecule is 32, whereas the total number of electrons in a CH4 molecule is 8.

CCl4 has a boiling point of 76.72 degrees, while methane has a boiling point of -161.6 degrees. The boiling point of CCl4 is significantly greater than that of methane.

CCl4 is a liquid at ambient temperature, whereas CH4 is a gas. Because there are more electrons in a CCl4 molecule than in methane, the intermolecular interactions are stronger.

The London dispersion forces between CCl4 molecules are higher than those between CH4 molecules.

A greater boiling or freezing point indicates that the intermolecular forces in that molecule are stronger.

CCl4’s Applications

CCl4 is used to make propellants for aerosol cans, refrigerants, oil solvents, rubber waxes, varnishes, and resins in large quantities.

It’s also utilised in the dry cleaning process.

To show stamp watermarks without causing damage to the stamp, carbon tetrachloride is utilised.

It’s also a key component in the creation of lava lamps.

FAQs

What influence do intermolecular forces of attraction have on a substance’s boiling point?

The stronger the intermolecular forces of attraction, the more difficult it will be to separate liquid molecules and allow them to vaporise. As a result, intermolecular interactions raise a substance’s boiling point.

What influence do intermolecular forces of attraction have on a substance’s melting point?

The amount of energy necessary to overcome intermolecular interactions and break bonds determines a substance’s melting point.

As a result, intermolecular forces of attraction raise a substance’s melting point.

Which is more powerful: intermolecular or intramolecular attraction?

Intramolecular attraction is stronger than intermolecular attraction. Because intramolecular forces exist between atoms in the same molecule, this is the case. They are responsible for holding the molecular structure together.

Intermolecular forces, on the other hand, are simple attractor forces that occur when molecules are in close proximity to one another. When the relationship is broken, the proximity is lost.

Conclusion

Carbon tetrachloride (CCl4) is a non-polar, tetrahedral chemical. Its dipole bonds between C and Cl cancel each each out. As a result, the London dispersion force is the only intermolecular attraction force observed.

These forces are caused by molecules being kept close together with enough room to form a transient dipole.

The impact of London dispersion forces, on the other hand, is dependent on the size and shape of the molecule.

Read more: Geometry, Hybridization, and Polarity of N2H4 Lewis Structure

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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