Stepwise combination of NH3 with BH4− in metal borohydride ammoniate

Abstract

Step-wise combination of NH₃ with BH₄⁻ was found to proceed in the AlCl₃·mNH₃–nLiBH₄ system. Firstly, only two N–H bonds of the NH₃ groups combined with B–H bonds at low temperature. Secondly, the residual N–H bonds could react further with excess B–H bonds at elevated temperature. This process is believed to be a common feature for many metal borohydride ammoniates.