High-pressure synthesis of a new copper hydride from elements

The paper presents a high-pressure X-ray diffraction investigations of copper subjected to high hydrogen pressure in a diamond anvil cell. Twenty years from the last high-pressure synthesis of a metal hydride (AuH), another hydride has been created under pressure from the elements. The formation of a new phase of copper hydride has been observed at pressure higher than 14.4 GPa. This copper hydride retains the fcc crystal structure of copper. The process of formation of the hydride phase is accompanied by a 7.5% increase of volume of the copper sample. The decomposition of cubic copper hydride takes place at pressures of around 12.5 GPa. The conditions of synthesis of the hydride in copper-hydrogen system, determined in these studies, are in good agreement with the values predicted on the basis of semi-theoretical models. (C) 2004 Elsevier Ltd. All rights reserved.