Aluminium borohydride
# Aluminium borohydride

Aluminium borohydride, also known as aluminium tetrahydroborate, is the chemical compound with the formula $Al(BH_4)_3.$ 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 $NaBH_4$ + $AlCl_3$ → $Al(BH_4)_3$ + 3 NaCl

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

    3 $Ca(BH_4)_2$ + 2 $AlCl_3$ → 3 $CaCl_2$ + 2 $Al(BH_4)_3$

## 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.

