Aluminum bromide

Structural formula
Aluminum bromide dimer: __ Al 3+      __ Br -
General
Surname	Aluminum bromide
other names	Aluminum (III) bromide Aluminum tribromide
Molecular formula	AlBr 3
Brief description	shiny, colorless leaflets
External identifiers / databases
CAS number 7727-15-3 EC number 231-779-7 ECHA InfoCard 100,028,891 PubChem 24409 ChemSpider 22818 Wikidata Q259311
properties
Molar mass	266.69 g mol −1
Physical state	firmly
density	3.2 g cm −3
Melting point	97.5 ° C
boiling point	263 ° C
Vapor pressure	1.3 h Pa (81 ° C)
solubility	explosive decomposition in water soluble in benzene and toluene
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 302-314 EUH: 014 P: 280-305 + 351 + 338-310
Toxicological data	1598 mg kg −1 ( LD 50 ,  rat ,  oral )
Thermodynamic properties
ΔH f 0	−516 kJ mol −1
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Aluminum bromide is an inorganic chemical compound made from bromine and aluminum with the empirical formula AlBr ₃ .

Extraction and presentation

Aluminum bromide can be synthesized by passing bromine vapor over a glowing mixture of carbon and aluminum oxide or by the direct action of bromine on aluminum.

${\displaystyle \mathrm {2\ Al+3\ Br_{2}\longrightarrow 2\ AlBr_{3}} }$

properties

The molar mass is 266.69 g / mol, its density 3.2 g / cm³. It has a melting point of 97.5 ° C and a boiling point of 263 ° C.

In the solid state, aluminum bromide forms Al ₂ Br ₆ molecules, in which two bromide ions appear as bridging ligands , causing the aluminum atom to reach an electron octet.

Aluminum bromide is soluble in benzene , toluene , carbon disulfide and many other organic solvents. It forms colorless rhombic crystals that smoke in moist air. It has a monoclinic crystal structure , space group P 2 ₁ / a (space group no. 14, position 3) , a = 1030.82 pm, b = 710.12 pm, c = 753.64 pm, β = 96.418 °.

Aluminum bromide reacts vigorously with water to form a strongly acidic solution. The Al-Br bonds are largely hydrolyzed here . Aluminum bromide crystallizes from the solution as the hexahydrate AlBr ₃ · 6 H ₂ O.

use

The main use of aluminum bromide is as a catalyst in organic syntheses such as, for example, polymerization , Friedel-Crafts reactions or bromination .

Individual evidence

1. ↑ ^{a b c d e f} Entry on aluminum bromide. In: Römpp Online . Georg Thieme Verlag, accessed on July 15, 2014.
2. ↑ ^{a b c} data sheet aluminum bromide (PDF) from Merck , accessed on January 19, 2011.
3. ↑ ^{a b c d} Entry on aluminum bromide in the GESTIS substance database of the IFA , accessed on January 8, 2018(JavaScript required) .
4. ↑ ^{a b} Yoffe, D .; Frim, R .; Ukeles, SD; Dagani, MJ; Barda, HJ; Benya, TJ; Sanders, DC: Bromine Compounds , in: Ullmanns Enzyklopädie der Technischen Chemie , Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2013; doi : 10.1002 / 14356007.a04_405.pub2 .
5. ↑ PAETEC formula collection 2003 edition, page 116.
6. ^ ^{A b} Douglas G. Nicholson et al .: Aluminum bromide . In: Ludwig F. Audrieth (Ed.): Inorganic Syntheses . tape 3 . McGraw-Hill, Inc., 1950, pp. 30-36 (English).
7. ↑ RW Berg, FW Poulsen, K. Nielsen: Redetermination of the crystal structure of Al ₂ Br ₆ . A comparison of three methods . In: Acta Chemica Scandinavica , 1997 , 51 , pp. 442-448. doi : 10.3891 / acta.chem.scand.51-0442 .