Is AlCL3 a covalent bond

Aluminum chloride (AlCl3): chemical structure, properties, use

Aluminum chloride or Aluminum trichloride (AlCl 3 ) is a binary salt that is formed from aluminum and chlorine. Sometimes it appears as a yellow powder because it has impurities due to the presence of ferric chloride.

It is obtained by combining its elements. Aluminum, which has three electrons in its last energy level (family IIIA), tends to give them due to its metallic character. Chlorine with seven electrons in its last energy plane (VIIA family) tends to attract them to complete its octet.

Although it is the bond between a metal and a non-metal, the bond formed between aluminum and chlorine in aluminum trichloride is believed to be covalent.

There are two types of aluminum chloride:

  • Anhydrous aluminum chloride. AlCl 3
  • Aluminum chloride hexahydrate. AlCl 3 6H 2 O. This compound can be in solid form or in solution.

Chemical structure

Anhydrous aluminum trichloride is a molecule with a planar trigonal geometry and an angle of 120 °, which corresponds to an atomic hybridization sp2.

However, the molecule is in the form of Organized dimers, in which a chlorine atom donates a pair of electrons to form bonds. These are known as coordinated covalent bonds.

In this way the organization of aluminum trichloride dimers is deduced.

This organization enables the compound to form networks of dimeric layers. When water is poured on the solid aluminum trichloride, they do not dissociate from the ionic compounds as expected, but undergo violent hydrolysis.

In contrast, the coordinated ions [Al (H 2 O) 6 ] +3 and the chloride. These structures are very similar to those of diborane.

In this way we have the formula Al 2 Cl 6

When the difference in the electronegativity of the atoms that make up the bonds in this compound is measured, the following can be observed:

For aluminum Al the value of electronegativity is 1.61 ° C and that of chlorine is 3.16 ° C. The difference in electronegativity is 1.55 ° C.

According to the rules of bond theory, to be ionic, a compound must have a difference in the electronegativity of the atoms that make up the bond, the value of which is greater than or equal to 1.7 C.

In the case of the Al-Cl bond, the difference in electronegativity is 1.55 C, which gives aluminum trichloride a covalent bond arrangement. This low value can be attributed to the coordinated covalent bonds that the molecule possesses.



Look : white solid, sometimes yellow due to ferric chloride contamination

density : 2.48 g / ml

molar mass : 133.34 g / mol

sublimation : sublimates at 178 ° C, therefore its melting and boiling points are very low.

Drive : Poorly conducts electricity.

solubility : It is not soluble in water because it is a Lewis acid. It is soluble in organic solvents such as benzene, carbon tetrachloride, and chloroform.


In the water, the aluminum trichloride is hydrolyzed, whereby the HCl and the hydronium ion and the aluminum hydroxide are formed:

It is used as a catalyst in Friedel - Crafts reactions (substance that can be recovered at the end of the reaction because it only accelerates, slows down or initiates one reaction).

It's a corrosive substance.

During the decomposition, aluminum oxide and dangerous gases such as hydrogen chloride are produced in a violent reaction with water.


  • Antiperspirant
  • Acrylation and alkylation catalyst from Friedel-Crafts.

Risks: possible effects

  • It is a corrosive substance that causes skin burns and serious eye damage.
  • Reacts violently with water.
  • It's dangerous for the environment.
  • Very toxic to aquatic organisms.


Avoid contact with the product without the necessary safety measures. Must be used, safety glasses, gloves, proper clothing, covered shoe.

After inhalation Inhaling dust can irritate the respiratory tract due to the corrosive effects of the substance. Symptoms include a sore throat, cough, and shortness of breath. Pulmonary edema symptoms can be delayed and severe cases can be fatal. Move the victim to an airy place free of debris. Give artificial respiration if necessary. Provide oxygen if breathing is difficult. Call the doctor.

In case of skin contact AlCl 3 is corrosive. It can cause irritation or burns with redness and pain. Wash immediately after contact with plenty of water for at least 20 minutes. Do not neutralize or add substances other than water. Take off contaminated clothing and wash it before reuse. If you are injured, contact your doctor immediately.

Upon contact with the eyes . AlCl 3 is corrosive. It causes severe pain, blurred vision, and tissue damage. Immediately flush eyes with water for at least 20 minutes, holding the eyelids open to ensure that the entire eye and the tissues of the eyelid are clear. To achieve maximum effectiveness, the eyes must be rinsed in seconds. If you have contact lenses, remove them after the first 5 minutes and then continue to rinse your eyes. Consult the doctor. It can seriously damage the cornea, conjunctiva, or other parts of the eye.

If swallowed . AlCl 3 is corrosive. Burning sensations can cause pain in the mouth and esophagus, and burn mucous membranes. It can cause gastrointestinal complaints with abdominal pain, nausea, vomiting and diarrhea. DO NOT VOMIT. Rinse out mouth and give water to drink. Never give anything by mouth to an unconscious person. Call the doctor. If vomiting occurs spontaneously, lay the victim on their side to reduce the risk of aspiration.

People with existing skin conditions or eye problems or impaired breathing function may be more susceptible to the effects of the substance

The packaging and storage of the AlCl 3 -Connection should be made in ventilated, clean and dry places.