What Is Carbon Tetrachloride?

Carbon tetrachloride is a colorless organic compound with the chemical formula CCl₄. The International Union of Pure and Applied Chemistry (IUPAC) name for this chemical is tetrachloromethane. Carbon tetrachloride is often used as an organic solvent, a fuel additive, a catalyst, a refrigerant or a metal de-greaser. Prolonged exposure to this chemical can be harmful to the liver, kidneys and central nervous system.

At room temperature, carbon tetrachloride is a colorless liquid. Its molecular weight is 153.8 grams per mol. The melting point of this compound is minus-9.4 degrees Fahrenheit (minus-23 degrees Celsius), and the boiling point is 170 degrees Fahrenheit (76.7 degrees Celsius). Carbon tetrachloride is soluble in organic solvents such as acetone, ethanol, benzene and carbon disulfide. It shows a slight degree of solubility in water.

Structurally, this compound has a carbon atom at its center, surrounded by four atoms of chlorine. This arrangement gives the compound a tetrahedral shape. There are many other names by which this chemical might be known, including carbon chloride, carbon tet, freon 10, halon-104 or tetrachlorocarbon.

The most common method of making carbon tetrachloride is to react chlorine with methane. Hydrochloric acid, HCl, is formed as a byproduct of the reaction. This is the most common method for producing CCl₄, but it also can be made by chlorinating compounds such as chloroform or dichloromethane.

Historically, carbon tetrachloride has been used in various applications, ranging from dry cleaning fluid to fire extinguishers. It often was used to manufacture refrigerants, but this practice has declined since the late 1980s, when many countries began adopting certain regulations to protect the environment. The refrigerants in question were found to be detrimental to the ozone layer. Usage in other commercial applications also has declined because of the health risks associated with the chemical.

Unlike many of its historical applications, carbon tetrachloride's modern applications tend to distance the user from the chemical itself. These applications generally are limited to the use in chemical processes such as catalysis or use as an organic solvent. The non-polar structure of the chemical makes it an excellent industrial de-greaser for metals.

Toxicity reports for carbon tetrachloride confirm it as a hepatotoxin, meaning that it can cause damage to the liver. Prolonged exposure might also result in damage to the central nervous system and kidneys. Symptoms of high exposure include general gastric problems, anorexia, headache, depressive symptoms and giddiness. Carbon tetrachloride also is a suspected carcinogen and should be handled with care.