Pure nanoparticle ammonia borane (NH3BH3,AB) was first prepared through a solvent-free, ambienttemperature gas-phase combination of B2H6 with NH3. The prepared AB nanoparticle exhibits improved dehydrogenation behavior giving 13.6 wt.% H2 at the temperature range of 80–1758C without severe foaming. Ammonia diborane (NH3BH2(m-H)BH3, AaDB) is proposed as the intermediate in the reaction of B2H6 with NH3 based on theoretical studies. This method can also be used to prepare pure diammoniate of diborane ([H2B(NH3)2][BH4], DADB) by adjusting the ratio and concentration of B2H6 to NH3.

Yuanzhou Song⁺,^[a] Nana Ma⁺,^[b] Xiaohua Ma,^{[a, c]} Fang Fang,^[a] Xuenian Chen,*^[b] and Yanhui Guo*^[a]. Synthesis of Ammonia Borane Nanoparticles and Diammoniate of Diborane by Direct Combination of Diborane and Ammonia.[J]. Chemistry, 2016, 22(18):6228-6233.
http://onlinelibrary.wiley.com/doi/10.1002/chem.201600367/pdf