LiAlH4 vs NaBH4: Key Differences in Reducing Power, Safety, and Use
LiAlH4 (lithium aluminium hydride) and NaBH4 (sodium borohydride) are reducing agents that donate hydride ions to convert carbonyls into alcohols; LiAlH4 is far stronger and moisture-sensitive, while NaBH4 is milder and water-tolerant.
Students swap them because both are white powders ending in “-hydride” and appear in the same textbook chart. In the wild, LiAlH4 powers pilot-scale kilo-lab reductions that must run bone-dry under argon, whereas NaBH4 sits calmly on benchtops in undergrad labs and even appears in some skin-care formulations.
Key Differences
Strength: LiAlH4 reduces carboxylic acids, esters, nitriles; NaBH4 stops at aldehydes and ketones. Solvent: LiAlH4 needs dry ether; NaBH4 works in water or ethanol. Safety: LiAlH4 ignites on contact with moisture; NaBH4 needs acid to release hydrogen and is far less pyrophoric.
Which One Should You Choose?
Pick LiAlH4 for stubborn substrates when you have inert atmosphere and fire suppression. Reach for NaBH4 for quick, safe carbonyl reductions in teaching labs or when open-air handling is required. Budget matters too: NaBH4 is cheaper and ships without hazmat surcharges.
Can I use NaBH4 to reduce an ester?
No; upgrade to LiAlH4 or another stronger reductant.
Why does LiAlH4 need argon but NaBH4 doesn’t?
LiAlH4 reacts violently with water, producing hydrogen gas and heat, while NaBH4 is stable in aqueous solution until acidified.