Sodium borohydride, 96%

Sodium borohydride, also known as sodium tetrahydridoborate and sodium tetrahydroborate, is an inorganic compound with the formula NaBH4. This white solid, usually encountered as a powder, is a versatile reducing agent that finds wide application in chemistry, both in the laboratory and on a technical scale. It has been tested as pretreatment for pulping of wood, but is too costly to be commercialized. The compound is soluble in alcohols and certain ethers but reacts with water in the absence of a base.

The compound was discovered in the 1940s by H. I. Schlesinger, who led a team that developed metal borohydrides for wartime applications (in particular, looking for a uranium compound more volatile than the hexafluoride to be used in isotope separation by gaseous diffusion; this line of research did not yield useful results.

Sodium borohydride is an odorless white to gray-white microcrystalline powder which often forms lumps. It can be purified by recrystallization from warm (50 °C) diglyme. Sodium borohydride is soluble in protic solvents such as water and lower alcohols; it will also react with these solvents to produce H2; however, these reactions are fairly slow. Complete decomposition in excess methanol can take nearly 90 min at 20 °C. It will decompose in neutral or acidic aqueous solutions but is stable at pH 14. These conditions can be exploited to allow sodium borohydride to react in a homogeneous manner, with reduced lifespan being traded against increased reactivity. The principal application of sodium borohydride is the production of sodium dithionite from sulfur dioxide: Sodium dithionite is used as a bleaching agent for wood pulp and in the dyeing industry.

Sodium borohydride reduces aldehydes and ketones to give the related alcohols. This reaction is used in the production of various antibiotics including chloramphenicol, dihydrostreptomycin, and thiophenicol. Various steroids and vitamin A are prepared using sodium borohydride in at least one step.

Sodium borohydride is used as reducing agent in the synthesis of gold nanoparticles. Sodium borohydride has been considered as a solid state hydrogen storage candidate. Although practical temperatures and pressures for hydrogen storage have not been achieved, in 2012 a core–shell nanostructure of sodium borohydride was used successfully to store, release and reabsorb hydrogen under moderate conditions.