Carbon Tetrachloride - CCl₄

Carbon Tetrachloride is a chemical that does not occur naturally. It is manufactured in the form of a clear liquid that can be detected at low levels. It is prepared by the chlorination of several hydrocarbons of low molecular weight. These include carbon disulfide, methane, ethane, and propane. It can also be prepared by thermal chlorination of methyl chloride. 

Carbon Tetrachloride is an important chemical and has several industrial uses. If you are a student of Chemistry, you must understand the properties, structure, and application of this chemical well. 

In this article, you will get familiar with Carbon Tetrachloride, its structure, its properties, potential sources, and applications. You will also read about the potential threat one can face if exposed to this chemical for a prolonged duration. Refer to the official website of Vedantu or download the app for a detailed and comprehensive explanation.

What is Carbon Tetrachloride?

Carbon tetrachloride is also called tetrachloromethane, which is an organic compound. The carbon tetrachloride formula is CCl4. The CCl4 molecule is often classified as a polyhalogenated organic compound because it consists of a carbon atom that is attached to more than one halide functional group. 

For pressure and temperature under standard conditions, CCl4 exists as a colourless liquid that emanates an odour of very sweet. The CCl4 chemical name can be given as Carbon Tetrachloride. Earlier, this compound was used widely in cleaning agents. Also, it is used in fire extinguishers and is known to serve as a precursor to various refrigerants.

Point to Note: This compound usage has been phased out by various governments because of its toxicity. A large quantity of carbon tetrachloride inhalation can cause serious damage to vital organs such as the liver and kidney. It can also exhibit negative effects on the CNS (Central Nervous System). Moreover, prolonged human exposure to carbon tetrachloride often leads to death.

Nomenclature

Carbon Tetrachloride is given the IUPAC name 1,1,1,1-tetrachloromethane. This name is given because the central atom is carbon and it is surrounded by the functional groups of four chlorine atoms.

Carbon Tetrachloride Explained

This compound was also used widely as a precursor to chlorofluorocarbons (CFCs). However, since the 1980s, the production of this compound has seen a sharp decline because of environmental concerns. Exposure to carbon tetrachloride can cause centrilobular hepatic necrosis. This compound is metabolized in our body into the trichloromethyl radical, which is highly reactive and can cause hepatocellular damage.

Structure of a CCl4 Molecule

Carbon tetrachloride molecules contain tetrahedral molecular geometry, where the central carbon atom is bonded to 4 chlorine atoms. The structure of CCl4 molecules can be illustrated as follows.

It makes a note that the 4 chlorine atoms are symmetrically positioned at every corner around the central carbon atom of the CCl4 molecule. The bonds between the chlorine and carbon atoms are covalent. It exhibits non-polar properties as a consequence of the molecular geometry of this compound. It is also noted that the molecular structure of CCl4 is quite the same as that of CH4 (methane gas).

Sources and Potential Exposure

• Individuals can be exposed to carbon tetrachloride compounds in the air from accidental releases from uses and production. It can be evaporated into the leach or air into groundwater from its disposal in landfills.

• It is a standard contaminant of indoor air; exposure sources appear to be products, including cleaning agents, used in the home or building materials.

• Workers who are involved directly in the use or manufacture of carbon tetrachloride are most likely to face significant exposures to carbon tetrachloride.

• Individuals can also be exposed to CCl4 molecules by drinking contaminated water.

Properties of Carbon Tetrachloride

Let us look at a few important physical properties and chemical properties of the CCl4 molecule, as listed below:

• The molar mass of carbon tetrachloride molecular weight is given by 153.81 gms per mole.

• This compound exists in the liquid state under standard conditions. It has a sweet odour and colourless appearance.

• This compound's density in its liquid state corresponds to 1.5867 gms per cubic centimetre.

• The melting point of this molecule is given as -22.93 ⁰C, whereas the boiling point corresponds to 76.72 ⁰C.

• The CCl4 molecule is not very soluble in water. The solubility of carbon tetrachloride at a temperature of 25 ⁰C in water is only 1 gram per litre (approximately). However, it should note that this compound is soluble in various organic solvents, including benzene, chloroform, ethers, alcohols, and formic acid.

• Carbon tetrachloride also crystallizes in a monoclinic crystal lattice.

• The coordination geometry of this molecule contains a tetrahedral shape, and the molecular shape is also tetrahedral. It can also be noted that carbon is the central atom in this scenario.

• The thermal or heat capacity of carbon tetrachloride is 132.6 Joules per mole-Kelvin.

• The standard molar entropy that is associated with this organic compound is given by 214.42 Joules per mole Kelvin.

Key Applications of Tetrachloromethane

Prior to the 1980s, the carbon tetrachloride compound's primary application was in the chlorofluorocarbons production for refrigeration. It was also used as a good component of a cleaning agent and fire extinguishers. However, the health hazards that are associated with this compound, including the serious environmental damage caused by chlorofluorocarbons, have been phased out by the governments of various countries. 

However, the compound is known to have other niche uses, where a few of them are listed below:

• Carbon tetrachloride compounds can be used as a chlorine source in a named reaction, called Appel reaction.

• It is also used to reveal watermarks placed on stamps without damage to the stamp in the process.

• This compound was also used as a component in lava lamp manufacturing.

• Historically, the CCl4 molecule has been used in NMR spectroscopy of the proton.

Health Hazards Associated with Carbon Tetrachloride

Carbon tetrachloride can be dangerous to health depending on the following factors:

• How often is a person exposed to Carbon tetrachloride?

• How much of the substance was ingested by someone?

• How long was the person exposed to Carbon tetrachloride?

Depending on these factors Carbon tetrachloride can have serious effects on a person's liver, kidney and nervous system. 

There are various ways in which a person can be exposed to Carbon tetrachloride. These include drinking, breathing its vapours or going in through a person's skin.

Carbon tetrachloride compound is a highly potent hepatotoxin that can cause serious liver damage. Also, this compound can damage the central nervous system (CNS) in high enough concentrations. 

Exposure to the CCl4 molecule for a prolonged duration often leads to coma or even death, and it has also been linked to kidney and cancer damage, sometimes.

How to avoid Carbon tetrachloride poisoning?

Although it is not likely to get exposed to large amounts of Carbon tetrachloride outside the places where it is manufactured due to the strict regulation of the chemical, people may get exposed to smaller amounts at homes. To avoid being exposed to Carbon tetrachloride in any amount:

• Check the labels of household products and look for safer chemical-free alternatives.

• Keep any dangerous chemical out of the reach of kids. 

• Any products containing Carbon tetrachloride used in the past must be discarded safely.

• If you are a worker at a Carbon tetrachloride manufacturing plant, make sure you wear the required protective equipment including masks, gloves and protective clothing all the time.

• Make sure all the products being used are correctly labelled. To avoid any confusion, store potent chemicals in their original containers.

• Carbon tetrachloride is a dangerous chemical and care must be taken at all times if dealing with such a chemical at any point. Prevention and safety are extremely important to avoid any disastrous effect on our health and of everyone else.

Symptoms of Carbon tetrachloride Poisoning:

Short term exposure to Carbon tetrachloride can cause headache, dizziness, lethargy, weakness, nausea, and vomiting. However chronic exposure can cause serious damage including death as mentioned previously. 

Treatment for Carbon Tetrachloride Poisoning:

Unfortunately, there is no sure shot treatment for Carbon tetrachloride poisoning. The course of treatment usually depends on the type of exposure. 

In case Carbon Tetrachloride gets in your eyes, wash your eyes well for a good amount of time and seek medical attention right away. If the chemical gets on your skin, immediately get rid of the contaminated clothes and wash the affected area thoroughly with soap. Also, seek immediate medical help. Medical help must be sought immediately if you inhale or swallow Carbon Tetrachloride.