CID 5943

CCl₄

Carbon tetrachloride

C 1
Cl 4

Ball-and-stick Stick Space-filling

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5 atoms, 4 single bonds, tetrahedral.

IUPAC name: tetrachloromethane
Molar mass: 153.811(42) g/mol
Atoms: 5
Shape: tetrahedral
SMILES: C(Cl)(Cl)(Cl)Cl
InChIKey: VZGDMQKNWNREIO-UHFFFAOYSA-N
PubChem CID: 5943

Made of

C Cl

Structural formula of carbon tetrachloride. Each unlabelled corner is a carbon atom. It shows which atoms are joined to which, not the shape. The model above shows the shape.

No consumer product uses carbon tetrachloride any more, according to the US Environmental Protection Agency (EPA). Industry still takes plenty: the 2023 US volume reported to EPA’s Chemical Data Reporting lay between 100 and 250 million pounds. It serves as a raw material for refrigerants, other chlorinated compounds and farm chemicals. Its IUPAC name, from the International Union of Pure and Applied Chemistry, is tetrachloromethane: methane with every hydrogen on its carbon exchanged for chlorine.

At room temperature it is a clear, colourless, heavy liquid with a sweetish smell, in the description of the National Toxicology Program (NTP). Its density, 1.594 g/cm³ at 20 °C on the figure of the Hazardous Substances Data Bank (HSDB), is greater than water’s, so it sinks. Water dissolves only 793 mg of it per litre at 25 °C. NIOSH, the US National Institute for Occupational Safety and Health, lists Freon 10 and Halon 104 among its trade names.

Structure and bonding

The readout counts 5 atoms and 4 single bonds. With Labels on, a C sits at the centre and a Cl caps every bond, with no H anywhere. In PubChem’s computed 3D model all four bonds are 1.781 to 1.782 Å long.

In Ball-and-stick the four chlorines sit at the corners of a tetrahedron, the arrangement Chem1 describes for four equivalent bonds round one carbon. The article on molecular shapes sets out why carbon takes it. All six Cl–C–Cl angles fall between 109.44° and 109.52°, calculated rather than measured. Seen along the line halving one Cl–C–Cl angle, the four chlorines outline a square, two in front of the carbon and two behind.

Space-filling swells the chlorines into large green spheres, leaving only small grey patches of carbon in the hollows between them. Chlorine’s electronegativity, its pull on shared electrons, is 3.16 against carbon’s 2.55. The viewer shows no partial charges, and the polarity article covers how bond dipoles combine.

Where it turns up

Nature makes none of it, in the account of ATSDR, the US Agency for Toxic Substances and Disease Registry. LOTUS, a natural-products database, records it in the plant Helianthus tuberosus, and the NTP reports that sunlight-driven reactions of certain chlorinated hydrocarbons form it in the lower atmosphere.

Released, it moves quickly into the air, where most of it stays, ATSDR notes. It had turned up at 425 or more of the 1,662 waste sites on the US National Priority List.

Most foods hold none that can be detected, the NTP reports. The US Total Diet Study still found traces in a few, smooth peanut butter and boiled beef frankfurters among them. Haz-Map, an occupational health database, counts taxidermy, the preparing and mounting of animal skins, among activities that bring exposure. Haz-Map records that EPA’s pesticide ban once spared one use, specimens enclosed in museum cases; all its pesticide registrations have now been cancelled, the NTP reports.

Why it matters

Large-scale US production began in 1907, the NTP records. In the early 1900s doctors gave carbon tetrachloride to kill intestinal worms and, briefly, as an anaesthetic. Until the mid-1960s it cleaned in factories and homes, spot removers included, and filled fire extinguishers, and Haz-Map lists dry cleaning among its past uses. Grain was fumigated with it until EPA cancelled that use in 1986.

Its harmful effects led to bans on the household and pesticide uses, in ATSDR’s account, and EPA ties the end of solvent use to its discovery as a carcinogen. The Clean Air Act Amendments of 1990 also scheduled it, with the chlorofluorocarbons (CFCs), for phase-out by 2000, though EPA lists several exemptions. Its breakdown releases chlorine, which attacks ozone as the ozone page describes.

Refrigerants, not households, took most of it: in 1986, by HSDB’s figures, 91 per cent went into CFC-11 and CFC-12, the second being dichlorodifluoromethane. EPA’s December 2024 rule lets only industrial and laboratory uses continue, among them a processing aid for vinyl chloride.

Properties

Properties of carbon tetrachloride Molar mass summed from IUPAC/CIAAW 2024 standard atomic weights; formula, atom and bond counts and PubChem's molecular weight from PubChem CID 5943.
Property	Value	Unit	Source
Molecular formula (Hill order)	CCl₄
Molar mass	153.811(42) g/mol	g/mol	IUPAC/CIAAW 2024
Carbon atoms	1
Chlorine atoms	4
Bonds	4
PubChem molecular weight	153.8 g/mol	g/mol	PubChem

Safety

Carbon tetrachloride is toxic if swallowed, inhaled or in contact with the skin, and EU classification gives it the signal word Danger. It is suspected of causing cancer under EU classification and may cause cancer under Japan’s, and NIOSH treats it as a potential occupational carcinogen. Heated to decomposition, it gives off toxic fumes including phosgene. The PubChem Laboratory Chemical Safety Summary and the NIOSH Pocket Guide card hold the full classification and the workplace exposure limits.

Questions

What shape is a carbon tetrachloride molecule?

Tetrahedral. One carbon sits at the centre with a chlorine at each of the four corners, and the molecule carries no hydrogen at all. Chem1 describes four equivalent bonds on a carbon atom as pointing to the corners of a tetrahedron, and the four C–Cl bonds here are alike. PubChem's computed model puts every Cl–C–Cl angle between 109.44° and 109.52° and every bond near 1.78 Å, values calculated rather than measured.

Does carbon tetrachloride damage the ozone layer?

Yes. Its breakdown products destroy ozone in the upper atmosphere, according to ATSDR, the US Agency for Toxic Substances and Disease Registry. Its ozone depletion potential, a measure of the ozone damage it does, is 1.2 on EPA's phase-out page. EPA's ozone-depleting substances list gives 1.1 under the Montreal Protocol and 0.82 from the World Meteorological Organization. That list puts its lifetime in air at 26 years, ATSDR at 30 to 100, and the National Toxicology Program probably 50.

How does carbon tetrachloride damage the liver?

The liver enlarges and its cells are damaged or killed, according to ATSDR, and the effects are worse in heavy drinkers. Liver tissue turns the compound into chloroform. One suggestion, in the Hazardous Substances Data Bank, is that a split carbon–chlorine bond gives free radicals, reactive fragments that then latch onto the sulfhydryl (S–H) groups of enzymes. In cultured rat liver cells, carbon tetrachloride made fat build up when the cells kept their cytochrome P450, a liver enzyme.

Is carbon tetrachloride still used today?

Only in industry: the US Environmental Protection Agency (EPA) says it has no consumer uses. Under EPA's December 2024 rule it may still serve as a raw material for hydrochlorofluorocarbons, hydrofluorocarbons, hydrofluoroolefins and perchloroethylene. It may also act as a processing aid in making vinyl chloride, and remove nitrogen trichloride during chlorine and caustic soda production. EPA counts as particularly important its part in making refrigerants, aerosol propellants and foam-blowing agents that add little to global warming.

Same shape (tetrahedral)

CHCl₃ Chloroform 5 atoms, 4 single bonds, tetrahedral.
CCl₂F₂ Dichlorodifluoromethane 5 atoms, 4 single bonds, tetrahedral.
CH₂Cl₂ Dichloromethane 5 atoms, 4 single bonds, tetrahedral.
CH₄ Methane 5 atoms, 4 single bonds, tetrahedral.
H₂SO₄ Sulfuric acid 7 atoms, 6 bonds, tetrahedral.