Structure, chemical bonds and anisotropy in hydrides IMC with CeNi3 and PuNi3 structure

Hydrides of CeNi3, ErNi3 and CeCO3 intermetallic compounds have been synthesised under low and high (up to 200 MPa) hydrogen pressure. The structure of the hydrides has been analysed by X-ray and neutron diffraction methods. All hydrides retain the structure of the initial alloys with expanded lattice. The positions and parameters of hydrogen and metallic atoms have been determined and it is established that the anisotropy of the lattice slowly increases for hydrides with high hydrogen concentration. Different anisotropy and expansion of the volume of the lattice CeNi3, CeCO3 and ErNi3 hydrides as have been shown depend of hydrogen concentration, blocks construction of the structure and are determined by the type of chemical bonds between hydrogen and the metallic sublattice, where hydrogen is a donor of the electron for d-metal and acceptor of the electron from f-metal. (C) 2007 Elsevier B.V. All rights reserved.