Interaction between lithium amide and lithium hydride

Pure lithium amide (LiNH2) decomposes to lithium imide and ammonia at temperatures above 300 degreesC. Lithium hydride, on the other hand, liberates hydrogen at temperatures above 550 degreesC. By thoroughly mixing these two substances and conducting temperature-programmed desorption (TPD), we noticed that hydrogen was produced at temperatures around 150 degreesC. Combined thermogravimetric (TG), X-ray diffraction (XRD), and infrared (IR) analysis revealed that lithium amide would react with lithium hydride and convert to hydrogen and lithium imide (or Li-rich imide). The reaction mechanism was investigated by isotopic exchange.