Aluminum Bromide

Aluminum Bromide Synthesis

Aluminum bromide, also known by its common name aluminum tribromide and IUPAC name tribromoalumane, is a hygroscopic compound represented by the chemical formula AlBr3 [1, 4]. Its dimeric form (Al2Br6) exists mainly in the solid phase [2].

Aluminum Bromide Identification

CAS Number 7727-15-3 [1]
PubChem CID 24409 [1]
ChemSpider ID 22818 [3]
UN Number 1725 [1]
NSC Number 87608 [1]
EC Number 231-779-7 [1, 4]
RTECS Number BD0350000 [4]
InChI Key PQLAYKMGZDUDLQ-UHFFFAOYSA-K [1]
Aluminum Bromide Formula

How is Aluminum Bromide Prepared

It is synthesized by the slow addition of pieces of aluminum foil to liquid bromine, and this direct bromination is represented by the following reaction [5]:

2Al + 3Br2 → 2AlBr3

The equation is highly exothermic and causes the aluminum foil to melt, producing heat and light [5].

Aluminum Bromide Synthesis

Reaction with Chlorine

When aluminum bromide reacts with chlorine, it undergoes single replacement to yield aluminum chloride and bromine, which is shown by the following balanced equation:

2AlBr3+ 3Cl2 → 2AlCl3 + 3Br2

Properties and Characteristics of Aluminum Bromide

General Properties

Molar Mass/Molecular Weight 266.69 g/mol [1, 4]

Physical Properties

Color and Appearance White to pale yellowish-red, lumpy powder (anhydrous form) [1, 4]
Odor Pungent [1]
Melting Point 97.5 °C, 207.5 °F (anhydrous) [1]
Boiling Point 255 °C, 491 °F (anhydrous) [1]
Density 3.2 g cm-3 [1, 4]
State of matter at room temperature Solid [1, 4]
Solubility Soluble in benzene, toluene, nitrobenzene, ether, methyl alcohol, and acetone [1]
Solubility in Water Highly soluble, partially hydrolyzes shown by a fuming solution and appearance of white precipitate
Heat Capacity (C) 100.6 J/(mol.K)
Lattice Constant (a, b, and c) 0.7512 nm, 0.7091 nm, and 1.0289 nm

Atomic Properties

Crystal Structure Monoclinic lattice [6]
Aluminum (III) Bromide Crystal Structure

What is It Used for

Although it does not have any significant commercial applications, its anhydrous form works as a catalyst for increasing the rate of Friedel-Crafts alkylation reaction [7, 8].

Is Aluminum Bromide Toxic

Exposure through inhalation and swallowing can cause acute toxicity [8]. Contact with skin and eyes can result in irritation, corrosion, and damage [8].

    References

  1. Aluminum Bromide (Compound) – Pubchem.ncbi.nlm.nih.gov
  2. Aluminum Bromide – Aluminumsulfate.net
  3. Aluminium Bromide – Chemspider.com
  4. Aluminum Bromide – Americanelements.com
  5. Reaction Between Aluminum and BromineChemed.chem.purdue.edu
  6. The Crystal Structure of Aluminum Bromide – Onlinelibrary.wiley.com
  7. Aluminium Bromide (T3D1720) – T3db.ca
  8. Aluminum Bromide – Chemicalbook.com

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