Lithium aluminium hydride (LiAlH4)

Lithium aluminium hydride, commonly abbreviated LAH, has the formula LiAlH4. It is prepared by reacting lithium hydride with aluminium chloride, 4LiH + AlCl3 → LiAlH4 + 3LiCl. LAH is a colourless solid that reacts violently with water, and even with atmospheric moisture, so it must be handled under strictly anhydrous conditions (typically in dry ether). Because it is such a ready source of hydride ion, LAH is widely used as a reducing agent in organic synthesis — for example, reducing an ester (R-CO-OR') in dry ether gives the corresponding alcohol plus R'-OH, and reducing a carboxylic acid (R-CO-OH) likewise gives the corresponding primary alcohol, R-CH2-OH, releasing wat …