What does borohydride mean?
A borohydride is the negatively charged ion BH₄⁻, formed when a single boron atom bonds to four hydrogen atoms, as well as any salt that contains this ion. The best-known example is sodium borohydride (NaBH₄), a white crystalline solid prized by chemists as a mild yet effective reducing agent: it readily converts aldehydes and ketones into alcohols without attacking many other functional groups, making it indispensable in organic synthesis and pharmaceutical manufacturing. Other borohydrides, such as potassium and lithium borohydride, find roles in bleaching, metal recovery, and research into hydrogen storage for fuel cells. Because the term belongs to technical chemistry, it is rarely encountered outside laboratory manuals, patents, and scientific papers, but within those fields it is a precise, everyday word. Its name transparently combines 'boron' and 'hydride', signalling its composition to anyone familiar with chemical nomenclature.
nounA borohydride is the univalent anion BH₄⁻ or any salt of this anion, in which four hydrogen atoms are bonded to a central boron atom. Borohydrides, especially sodium borohydride and lithium aluminium hydride analogues of boron chemistry, are widely used as reducing agents.
- The univalent anion BH₄⁻, consisting of a boron atom bonded to four hydrogen atoms.
- Any salt or compound containing this anion, such as sodium borohydride (NaBH₄) or potassium borohydride (KBH₄).
"The chemist added sodium borohydride dropwise to reduce the aldehyde to an alcohol."
"Sodium borohydride is commonly used to reduce ketones to secondary alcohols."
"Researchers investigated borohydride compounds as a medium for storing hydrogen in fuel cells."
The plural typically denotes various borohydride compounds collectively, such as sodium, potassium, and lithium borohydrides.
"Several borohydrides have been evaluated for on-board hydrogen storage."
Sodium borohydride is gentle enough to be handled in a student lab, yet it can strip oxygen off molecules so selectively that it's a staple reagent in everything from pharmaceutical synthesis to paper bleaching — and it has even been explored as a way to store hydrogen fuel.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of borohydride
The word borohydride is a modern coinage of chemical nomenclature, combining 'boro-', derived from boron, with 'hydride', the standard term for binary compounds of hydrogen. Boron itself takes its name from borax, whose English form traces through medieval Latin and Arabic (buraq) origins, while 'hydride' derives ultimately from the Greek element 'hydro-' meaning water, via the term hydrogen coined in the late eighteenth century. The term arose alongside the systematic naming of hydride salts in nineteenth- and twentieth-century inorganic chemistry, once compounds such as sodium borohydride were characterised.
How borohydride is actually used
Strictly a technical term of chemistry; it appears almost exclusively in scientific writing, laboratory protocols, and materials science literature rather than general prose. In speech, chemists often name specific borohydrides directly (e.g. 'sodium borohydride') rather than referring to 'the borohydride' generically.
Easily confused with borohydride
A borate is a compound containing boron bonded to oxygen atoms (as in borax), whereas a borohydride contains boron bonded to hydrogen.
A hydride is any binary compound of hydrogen with another element, while a borohydride is the specific anion or salt featuring boron bonded to four hydrogens.