Thermal crystalline-to-amorphous transition of beryllium hydride

An irreversible thermally induced solid-state phase change in crystalline beryllium hydride has been discovered, with the product being amorphous or glassy beryllium hydride. The phase change was observed using simultaneous differential thermal analysis/thermogravimetric analysis and using X-ray diffraction. The phase change takes place at 485–550 K, just below the thermal decomposition temperature of 570 K. There is slight decomposition of the beryllium hydride during the phase change of about 5±2%. The enthalpy change associated with the phase transition is 2.3±0.7 kJ mol−1.