Although the transformation of the tetrahedral [AlH4](-) to the octahedral [AlH6](3-) occurs at high temperature, it was realized by ball milling (BM) of LiAlH4 at ambient temperature in the presence of LiNH2. Instead of a catalytical role, we found that LiNH2 may react with LiAlH4 to form an intermediate with a 1:1 stoichiometry. Our results show that a total amount of about 8 wt% H-2 can be detached from the mixture of LiAlH4-LiNH2 which is potential for an effective hydrogen storage system. Calculations combined with DSC measurements result in a very low enthalpy effect of the H-2 release reaction, further implying a possible reversibility in hydrogen storage. (c) 2006 Elsevier B.V. All rights reserved.