Lithium aluminium hydride (LiAlH4), commonly abbreviated to LAH, is a powerful reducing agent used in organic chemistry. It is more powerful than the related reducing agent sodium borohydride due to the weaker Al-H bond compared to the B-H bond. It will convert esters, carboxylic acids and ketones to alcohols; and nitro compounds into amines.
LAH violently reacts with water, including atmospheric moisture, and the pure material is pyrophoric. Commercial material is inhibited with mineral oil to allow handling in air.
Pure, recrystallized (from diethyl ether) LAH is a white solid. Commercial samples are almost always grey due to trace contamination with aluminium metal. White air-exposed commercial samples of LAH have absorbed enough moisture to become a mixture of lithium hydroxide and aluminium hydroxide.