Carbon tetrachloride (CCl4) is a colourless, sweet-smelling liquid. CCl4 occurs as a liquid at normal temperature. Its melting point is around -23 degrees Celsius. The temperature at which it boils is 76 degrees Celsius.
The toxic gas CCl4 depletes the ozone layer and is commonly referred to as a greenhouse gas.
It was once a common solvent in organic chemistry, but it is now rarely used due to its negative health effects.
In the year 1839, a French chemist named Henri Victor Regnault created tetrachloromethane for the first time. It was made by combining chloroform and chlorine.
Tetrachloromethane is now produced by combining chlorine with methane. The reaction is as follows:
CCl4 + 4 HCl = CH4 (Methane) + 4Cl2 (Chlorine) (acid)
Is the covalent molecule CCl4 (carbon tetrachloride)? We’ll find out in the next section.
A CCl4 molecule is made up of four chlorine atoms and one carbon atom. Four chlorine atoms share electrons with the four valence electrons of carbon, resulting in entire outer shells for all five atoms. Each chlorine atom is one electron shy of an octet configuration (complete shell), and carbon is four electrons short of a complete valence shell of eight.
Because the bond between carbon and chlorine is established by sharing electrons, it is called a covalent bond. As a result, CCl4 is a covalent molecule.
Because the outer electrons of chlorine and carbon atoms are shared, chlorine has the electronic configuration of argon and carbon has the electronic configuration of neon.
As a result, both the chlorine and carbon atoms have outer shells with eight electrons when establishing covalent connections.
That was a succinct response. Let me now go over the covalent nature of CCl4 in further depth.
Let’s start with the basics before delving into the specifics of covalent bonding in methane. First, I’ll go over the different sorts of bonds.
Ionic bonds are a type of ionic bond that
The permanent movement of valence (outermost) electrons from one atom to another results in the development of an ionic connection.
These connections are formed by electrostatic attraction between positively and negatively charged ions.
A positively charged ion or cation is formed when an atom loses electrons, whereas a negatively charged ion or anion is formed when an atom gets electrons.
Covalent Bonds are a type of chemical bond that exists between two
The elements with the highest ionisation energy cannot lose electrons, while the elements with the lowest electron affinity cannot take them.
The atoms of such elements try to share electrons with other elements’ atoms or with atoms of the same element, resulting in an octet arrangement in both valence shells.
Based on the electronegativity difference, a covalent bond might be polar or nonpolar.
Covalent bond that isn’t polar.
When two atoms share electrons evenly, they produce a non-polar covalent connection. The electronegativity difference between the connected atoms is usually relatively minimal in a non-polar covalent bond.
It also implies that there is no charge gap between the two atoms and that their electronegativity is the same.
Covalent Polar Bond
The unequal sharing of electron pairs between two atoms forms a polar covalent bond.
The electronegativity gap between the bound atoms should be between 0.4 to 1.7 on the Pauling scale, or about 2.
Factors Affecting Covalent Bond Formation
Several factors influence the development of the covalent bond between the atoms, as indicated below:
Energy of ionisation
The number of valence electrons in a molecule.
Size of an atom
Let me explain how these circumstances favour a covalent bond in greater detail.
The energy difference that happens when an atom gets a valence electron is referred to as this. When the interacting atoms have similar electron affinities, the creation of a covalent bond is preferred.
Ionization Energy at a Maximum
Covalent bonds are preferred by atoms with high ionisation energies.
The fundamental reason for this is that they are incapable of forming cations. This is due to the fact that they have a hard time losing their valence electrons, which are required for ionic bonding.
Chlorine has an extremely high ionisation energy of 1251.2 kJ/mole, whereas carbon has an ionisation energy of 1086.5 kJ/mole. Because both elements have a high ionisation enthalpy, it is easier to create a covalent link between them.
The lower atomic size is another feature that aids in the formation of a strong covalent bond.
The covalent radius is used to determine how far away the participating valence electrons of both atoms are when creating covalent bonds between them.
In the instance of generating a covalent radius, each atom’s covalent radius would be half the distance between the two nuclei.
Because an equal amount of valence electrons participate and are present at an equal distance from one another, as well as with an equal force of attraction on the other atom, this is the case.
As a result, the closer an atom is to the nucleus, the smaller it is. The electrons would be attracted to the atom by high molecular attraction, making it impossible for them to escape.
As a result, rather than totally transferring electrons via an ionic link, the atom would prefer a covalent bond based on electron sharing.
The development of a covalent bond is facilitated by the lower size of both chlorine and carbon atoms.
It is the quality of an atom that causes it to attract the mutual electron pair. The electronegativity of atoms can be calculated using the Pauling scale.
Chemical bonds in which the electronegativity difference between two atoms in a chemical bond is more than 2.0 are referred to be ionic bonds (In some texts it is mentioned as 1.7). A covalent bond is present if the difference is less than 2.0 on the Pauling scale.
The electronegativity of chlorine is 3.16, while that of carbon is 2.55. Carbon and hydrogen have an electronegativity differential of 3.16 – 2.55 = 0.61. The C-Cl bond is polar because of this difference in electronegativity. As a result, the four C-Cl bonds each have a dipole moment value.
Let’s figure out whether CCl4 is a polar or non-polar molecule.
The carbon atom’s outermost shell possesses four electrons, all of which participate in the formation of covalent bonds with four chlorine atoms, leaving the carbon atom with no lone pair.
Carbon tetrachloride generates sp3 hybridization with one s orbital and three p orbitals. The CCl4 molecule has a tetrahedral geometry with a bond angle of roughly 109.5 degrees.
Because all four bonds (C-Cl) are symmetrical and have an equal charge distribution, the dipole moment is cancelled by the tetrahedral molecular geometry of CCl4. As a result, CCl4 is non-polar.
The number of Valence Electrons is the number of electrons in a valence atom.
The creation of a covalent bond is preferred when each of the combining atoms possesses 5, 6, or 7 electrons in its valence shell. Non-metals from the Oxygen, Nitrogen, and Halogen families tend to form covalent bonds because of this.
Carbon covalent bonding is a specific instance that is briefly described below:
Carbon Atom Covalent Bonding
Carbon’s electrical structure must gain or lose four electrons to become stable, which is implausible because:
- Because six protons cannot carry ten electrons, carbon cannot receive four electrons to produce a carbon anion (C4-), causing the atom to become unstable.
- Carbon can’t give four electrons to form a carbocation (C4+) since it would require too much energy, and C4+ would only have two electrons retained by the proton, rendering it unstable once more.
Because carbon cannot take or donate electrons, the only choice is to share electrons in order to fulfil the closest noble gas configuration and form a covalent bond.
As a halogenation solvent and an industrial fumigant, it’s widely used.
It’s a great source of chlorine for creating organic molecules that include chlorine.
The CCl4 molecule is also useful in NMR spectroscopy due to its absence of hydrogen atoms.
Because it prevents fires by suppressing fire flames, carbon tetrachloride is commonly utilised in fire extinguishers.
Neutrinos are detected using this technique.
Used in stamp collecting and to disclose watermarks on postage stamps.
The symmetrical molecule Carbon Tetrachloride, or CCl4, has four chlorine atoms bonded to a central carbon atom. Its geometry is tetrahedral. It forms a covalent C-Cl bond due to the strong electron affinity and tiny size of the carbon and chlorine atoms.
Because of the electronegativity mismatch, the bond is a polar covalent bond. Because the dipole moments cancel out, the molecule as a whole is non-polar.
I’ve gone through the fundamentals of chemical bonding and the nature of bonds in CCl4 in this article. In the comments section, please feel free to ask any questions you may have. We’ll get back to you as soon as possible.
Read more: Is CO2 a Polar or Nonpolar Substance?