Aluminium Chloride Formula
The Aluminium Chloride formula is AlCl3. This compound has Aluminium in the +3 oxidation state, and chlorine is in the -1 oxidation state.
Physical Properties of Aluminium Chloride
Appearance:
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).
Solubility:
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.
Chemical Properties of Aluminium Chloride
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.