Boiling point 44.5 °C | Appearance colorless liquid | |
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Aluminium borohydride, also known as aluminium tetrahydroborate, (in American English, aluminum borohydride and aluminum tetrahydroborate, respectively) is the chemical compound with the formula Al(BH4)3. It is a volatile pyrophoric liquid which is used as rocket fuel, and as a reducing agent in laboratories. Unlike most other metal–borohydrides, which are ionic structures, aluminium borohydride is a covalent compound.
Contents
Preparation
Aluminium borohydride is formed by the reaction between sodium borohydride with aluminium chloride:
3 NaBH4 + AlCl3 → Al(BH4)3 + 3 NaClor as the non-pyrophoric tetrahydrofuran (THF) adduct, by the analogous reaction of calcium borohydride and aluminium chloride in THF:
3 Ca(BH4)2 + 2 AlCl3 → 3 CaCl2 + 2 Al(BH4)3Reactions
Like all borohydrides, this compound is a reducing agent and hydride donor. It reacts with water to give elemental hydrogen gas, and reduces carboxylic esters, aldehydes, and ketones to alcohols.