Ball-and-stick model of the borohydride anion, BH4

A borohydride is a compound containing the tetrahydridoborate(III) ion, BH4. Borohydride is a term also used for compounds containing BH3CN- (cyanotrihydroborate) and BH(C2H5)3- (triethylborohydride). Such compounds are mainly used as reducing agents in organic synthesis. The most important borohydride is sodium borohydride, but other salts are well known (see Table).[1]

Coordination complexes [link]

Borohydrides are excellent ligands for metal ions. In most such compounds, the BH4- ligand is bidentate. The binary borohydrides containing only BH4- ligands are often fairly volatile. One example is uranium borohydride.


Selected Properties of Various Borohydride Salts
Hydride CAS registry number Mol.Wt. Hydrogen Density Density g/cm3 m.p. (°C) solubility in water (g/100 mL, 25 °C) solubility in CH3OH (g/100 mL, 25 °C) solubility in ether (g/100 mL, 25 °C) solubility in THF (g/100 mL, 25 °C)
LiBH4

[16949-15-8]

21.78 18.5 0.66 280 20.9 decomp. (44 in EtOH) 4.3 22.5
NaBH4

[16940-66-2]

37.83 10.6 1.07 505 55 16.4 (20 °C) insol. 0.1 (20 °C)
NaBH3CN

[25895-60-7]

62.84 6.4 1.20 240 with deccomp. deccomp. 217 insol. 36
KBH4

[13762-51-1]

53.94 7.4 1.17 585 (under H2) 19 insol. insol. insol.
LiBH(C2H5)3

[22560-16-3]

105.94 0.95 unknown unknown decomp. decomp. na high (supplied commercially)

References [link]

  1. ^ Peter Rittmeyer, Ulrich Wietelmann “Hydrides” in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a13_199

https://wn.com/Borohydride

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