Studies of the thermal decomposition of copper hydride

Decomposition of copper hydride has been investigated by differential scanning calorimetry (DSC) and the thermogravimetric analysis (TGA) methods. The samples were prepared from aqueous solution by reduction of copper sulfate with hypophosphorous acid. The crystal structure was determined by energy dispersive X-ray diffraction method. Mass spectrometric and volumetric methods were used for the determination of hydrogen concentration in solid CuH. A special procedure was employed to obtain sample free of water and other contaminations in order to avoid obstacles from the impurity-related processes, in our opinion, responsible for the discrepancies in the thermodynamic properties of copper hydride. The enthalpy of pure copper hydride was found to be 27.5 +/- 0.4 KJ mol(-1). The activation energy was calculated from DSC data as about 73.7 kJ mol(-1). The equilibrium pressure of hydrogen over copper hydride and the possibility of copper hydride formation at high pressure from the elements will be discussed. (C) 2000 Elsevier Science B.V. All rights reserved.