Stepwise combination of NH3 with BH4(-) in metal borohydride ammoniate.
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.