Ammonium octahydrotriborate (NH4B3H8): new synthesis, structure, and hydrolytic hydrogen release

A metathesis reaction between unsolvated NaB3H8 and NH4Cl provides a simple and high-yield synthesis of NH4B3H8. Structure determination through X-ray single crystal diffraction analysis reveals weak N—Hδ+- - -Hδ-—B interaction in NH4B3H8 and strong N—Hδ+—Hδ-—B interaction in NH4B3H8·18-crown-6·THF adduct. Pyrolysis of NH4B3H8 leads to the formation of hydrogen gas with appreciable amounts of other volatile boranes below 160°C. Hydrolysis experiments show that upon addition of catalysts, NH4B3H8 releases up to 7.5 materials wt % hydrogen.