Towards hydrogen-rich ionic (NH 4 )(BH 3 NH 2 BH 2 NH 2 BH 3 ) and related molecular NH 3 BH 2 NH 2 BH 2 NH 2 BH 3 .

Attempts of the synthesis of ionic (NH 4 )(BH 3 NH 2 BH 2 NH 2 BH 3 ) via a metathetical approach resulted in a mixture of the target compound and partly dehydrogenated molecular NH 3 BH 2 NH 2 BH 2 NH 2 BH 3 product. The mixed specimen was characterised by NMR and vibrational spectroscopies, and the cocrystal structure was analyzed from powder X-ray diffraction data supported by theoretical density functional theory calculations. The compound crystallises in a P 2 1 / c unit cell with the lattice parameters of a = 13.401(11) Å, b = 13.196(8) Å, c = 17.828(12) Å, β = 128.83(4)°, V = 2556(3) Å 3 and Z = 16. Despite their impressive hydrogen content, similar to ammonia borane, both title compounds release hydrogen substantially polluted with borazine and traces of ammonia and diborane.