Aluminium chloride

Aluminium chloride (AlCl₃) is a sodium chloride. It exists in the solid state as a six-coordinate layer lattice.

AlCl₃ adopts the "YCl₃" structure, featuring Al³⁺ cubic close packed layered structure.^[2] In contrast, AlBr₃ has a more molecular structure, with the Al³⁺ centers occupying adjacent tetrahedral holes of the close-packed framework of Br⁻ ions. Upon melting AlCl₃ gives the dimer Al₂Cl₆, which can BF₃.

Aluminium chloride is highly hydrolysis of the Al³⁺ ion is occurring. The reactions can be described (simplified) as:

[Al(H₂O)₆]³⁺ + H₂O ⇌ [Al(OH)(H₂O)₅]²⁺ + H₃O⁺

AlCl₃ is probably the most commonly used hydrocarbons. Aluminium also forms a lower chloride, aluminum(I) chloride (AlCl), but this is very unstable and only known in the vapour phase.^[1]

Chemical properties

Aluminium chloride is a powerful chloride ion.

In water, partial hydrolysis forms sodium hydroxide:

AlCl₃(aq) + 3 NaOH(aq) → Al(OH)₃(NaCl(aq)

Preparation

Aluminium chloride is manufactured on a large scale by the exothermic reaction of aluminium metal with chlorine or hydrogen chloride.^[1]

2 Al + 3 Cl₂ → 2 AlCl₃

2 Al + 6 HCl → 2 AlCl₃ + 3 H₂

Hydrated forms are prepared by dissolving aluminium oxides with hydrochloric acid.

Uses

The aromatic system as shown:^[3]

With dysprosium(III) triflate, which can be recycled.

Aluminium chloride can also be used to introduce catalyst):^[4]

Aluminium chloride finds a wide variety of other applications in carvone:^[6]

AlCl₃ is also widely used for detergents.

Aluminium chloride combined with aluminum in the presence of an arene can be used to synthesize bis(arene) metal complexes, e.g. Fischer-Hafner synthesis.

Aluminum chloride, often in the form of derivatives such as aluminium chlorohydrate, is a common component in antiperspirants at low concentrations. Hyperhidrosis sufferers need a much higher concentration (15% or higher), sold under such brand names as Drysol®, Maxim®, Odaban®, CertainDri®, B+Drier® and Driclor®.

Precautions

Anhydrous AlCl₃ reacts vigorously with bases, so suitable precautions are required. Hydrated salts are less problematic.

References

1. ^ ^{a b c d e} N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, Pergamon Press, Oxford, United Kingdom, 1984.
2. ^ A. F. Wells, Structural Inorganic Chemistry, Oxford Press, Oxford, United Kingdom, 1984.
3. ^ ^{a b c} G. A. Olah (ed.), Friedel-Crafts and Related Reactions, Vol. 1, Interscience, New York, 1963.
4. ^ L. G. Wade, Organic Chemistry, 5th edition, Prentice Hall, Upper Saddle River, New Jersey, United States, 2003.
5. ^ P. Galatsis, in: Handbook of Reagents for Organic Synthesis: Acidic and Basic Reagents, (H. J. Reich, J. H. Rigby, eds.), pp12-15, Wiley, New York, 1999.
6. ^ B. B. Snider, Accounts of Chemical Research 13, 426 (1980).