The Aluminium Chloride formula is AlCl3. This compound has Aluminium in the +3 oxidation state, and chlorine is in the -1 oxidation state.
The different physical forms of Aluminium chloride are :
Anhydrous Aluminium Chloride: It is a white or colorless solid that is often utilized as a catalyst in organic chemistry.
Hydrated Forms: For example, Aluminium Chloride hexahydrate has water of crystallization attached.
Anhydrous Aluminium Chloride is a strong Lewis acid and is used extensively in chemical reactions, such as Friedel-Crafts alkylation and acylation.
Melting point and boiling point: The melting point of anhydrous Aluminum Chloride (AlCl3) is 192.6°C (378.7°F) and its boiling point is 180°C (356°F).
Water: Anhydrous Aluminium Chloride has an extraordinarily high degree of solubility in water, reacting exothermically to give Hydrochloric acid and Aluminium Hydroxide.
AlCl3+3H2O→Al(OH)3+3HCl
Organic solvents: It also dissolves in several organic solvents such as Benzene and Chloroform.
Hygroscopicity: Anhydrous Aluminium Chloride is highly hygroscopic since it readily absorbs moisture from the atmosphere. This property might render it deliquescent, that is, dissolving in its absorbed water.
Lewis acid behavior: Aluminium Chloride is a Lewis acid and, therefore, accepts electron pairs. In this respect, the chemical finds its application as an effective catalyst in many chemical processes, especially in organic syntheses.
Reaction with water: Aluminium Chloride reacts with water violently to eventually form Hydrochloric acid along with Aluminium Hydroxide:
AlCl3+3H2O→Al(OH)3+3HCl
This reaction is highly exothermic and can be dangerous due to the release of HCl gas.
Friedel-Crafts reactions: It finds wide application as a catalyst in the Friedel-Crafts alkylation and acylation reactions. In this reaction, it forms carbocation intermediates. Carbocation thus formed can attach alkyl or acyl groups with aromatic rings.
Reaction with bases: Aluminium Chloride is hydrolyzed with strong bases to give Aluminium Hydroxide and Sodium Chloride.
With sodium hydroxide,
AlCl3+3NaOH→Al(OH)3+3NaCl
Sublimation: Aluminum Chloride sublimes on heating; that is, it changes straight from solid to gas without going into the liquid phase. The sublimation point is around 180°C
Solid-state dimer: The solid-state of Aluminium Chloride usually exists as a dimer, where every Al atom is surrounded by six Cl atoms in the shared structure.
Organic solvents solubility: It has good solubility in most of the organic solvents such as Benzene and toluene. It acts as a catalyst in many organic synthesis reactions.
Decomposition: Higher temperatures will decompose aluminum chloride into Aluminum Oxide and Chlorine gas.
These properties make Aluminum Chloride a versatile reagent in both industrial and laboratory.