Chemistry:Aluminium borohydride

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Aluminium borohydride[1]
Structural formula of the aluminium borohydride molecule
Names
IUPAC name
Aluminium borohydride
Other names
Aluminium borohydride, aluminium tetrahydroborate
Identifiers
3D model (JSmol)
ChemSpider
UNII
UN number 2870
Properties
AlB3H12
Molar mass 71.51 g·mol−1
Appearance colorless liquid
Melting point −64.5 °C (−84.1 °F; 208.7 K)
Boiling point 44.5 °C (112.1 °F; 317.6 K)
reacts
Hazards
Flash point Spontaneously ignites
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Aluminium borohydride, also known as aluminium tetrahydroborate, is the chemical compound with the formula Al(BH4)3. It is a volatile pyrophoric liquid which is used as a reducing agent in laboratories. Unlike most other metal–borohydrides, which are ionic structures, aluminium borohydride is a covalent compound.[2][3]

Preparation

Aluminium borohydride is formed by the reaction between sodium borohydride with aluminium chloride:[4]

3 NaBH4 + AlCl3 → Al(BH4)3 + 3 NaCl

or as the non-pyrophoric tetrahydrofuran (THF) adduct, by the analogous reaction of calcium borohydride and aluminium chloride in THF:[2]

3 Ca(BH4)2 + 2 AlCl3 → 3 CaCl2 + 2 Al(BH4)3

Reactions

Like all borohydrides, this compound is a reducing agent and hydride donor. It reacts with water to give elemental hydrogen gas,[4] and reduces carboxylic esters, aldehydes, and ketones to alcohols.[2]

References

  1. Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, Florida: CRC Press. pp. 4–39. ISBN 0-8493-0594-2. 
  2. 2.0 2.1 2.2 J. Kollonitsch & O. Fuchs (1955). "Preparation of Aluminium Borohydride and its Applications in Organic Reductions". Nature 176 (4492): 1081. doi:10.1038/1761081a0. Bibcode1955Natur.176.1081K. 
  3. Miwa, K.; Ohba, N.; Towata, S.; Nakamori, Y.; Züttel, A.; Orimo, S. (2007). "First-principles study on thermodynamical stability of metal borohydrides: Aluminum borohydride Al(BH4)3". J. Alloys Compd. 446–447: 310–314. doi:10.1016/j.jallcom.2006.11.140. 
  4. 4.0 4.1 Perry, Dale L.; Phillips, Sidney L. (1995). Handbook of Inorganic Compounds. CRC Press. pp. 3–4. ISBN 0-8493-8671-3. https://books.google.com/books?id=0fT4wfhF1AsC. Retrieved 2007-12-09. 

Further reading

  • Fletcher, Edward; Foster, Hampton; Straight, David (1959). "Aluminum Borohydride and Mixtures with Hydrocarbons in Jet Engine Combustor Ignition". Industrial & Engineering Chemistry 51 (11): 1389. doi:10.1021/ie50599a044. 
  • Hinkamp, James B.; Hnizda, Vincent (1955). "Aluminum Borohydride Preparation". Industrial & Engineering Chemistry 47 (8): 1560. doi:10.1021/ie50548a032.