Aluminium borohydride

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.

Preparation
Aluminium borohydride is formed by the reaction between sodium borohydride with aluminium chloride:
 * 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:


 * 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, and reduces carboxylic esters, aldehydes, and ketones to alcohols.