The dependence of chemical reaction between Mg(NH2)(2) and MgH2 on the ball-milling conditions has been investigated. While the decomposition of the component Mg(NH2)(2) resulted in gaseous products consisting mainly of ammonia, the mixtures of Mg(NH2)(2)-MgH2 prepared by ball-milling released H-2 at temperatures as low as 65 degrees C. In addition, the increase in ball-milling time can effectively suppress the ammonia evolution during the thermal treatment. The conversion of the amide and hydride to imide-like structure was demonstrated by FTIR and XRD characterization. A total amount of 4.8 wt.% of H-2 could be released from the investigated system. (c) 2006 Elsevier B.V. All rights reserved.