Given its high hydrogen gravimetric density, ammonia may be utilised as a hydrogen carrier, and thus ammonia stores are an area of interest. It is known that Mg(BH4)2 takes up ammonia to form the adduct Mg(NH3)6(BH4)2, which decomposes to release 4 molar equivalents of ammonia at 80°C and then 7 molar equivalents of hydrogen at 125°C. We request 3 days on HRPD in conjunction with the IGAn apparatus and quartz reactor to investigate the interaction of fully isotopically enriched Mg(11BD4)2 with ammonia (ND3) gas, by simultaneous neutron diffraction and thermogravimetric analysis. These experiments will allow us to fully characterise the structure of the known phases of Mg(ND3)6(11BD4)2 and Mg(ND3)2(11BD4)2, identify any reaction intermediates, produce information as to the mechanism, decomposition pathway and the final decomposition product.