Denys R. Structural peculiarities and physicochemical properties of new hydrides of ternary compounds of RE metals of cerium subgroup with metals of the iron triad and B, Ga or In

The interaction of Nd5Co2B6, Nd6Fe13Ga and RNiIn (R= La, Ce, Nd, Pr) ternary intermetallic compounds with hydrogen have been studied with the use of methods of powder X-ray and neutron diffraction, crystal chemistry analysis, differential thermal analysis, thermodesorption spectroscopy, electron microscopy. The hydride formation was found to depend on the temperature of the process. At low temperature all studied compounds form interstitial hydrides with retaining symmetry of metallic matrix. At high temperature the Nd5Co2B6 and Nd6Fe13Ga compounds disproportionate with the formation of neodymium hydride and other phases. For the Nd5Co2B6 the HDDR process was studied in details. The crystal structure of the interstitial hydrides was determined. In the hydrides of RNiIn compounds the formation of H...H pairs with short interatomic distances ~0,16 nm, as well as the insertion of hydrogen atoms into interstices with In in surrounding have been observed for the first time for metal hydrides. The correlation between crystal structure of intermetallic compounds and hydrides and their hydrogenation and physico-chemical properties has been studied. The spheres of use are hydride materials science, inorganic chemistry and crystal chemistry.