NEW COMPOUNDS IN THE 30-40-AT-PERCENT RU RANGE OF THE RARE-EARTH RUTHENIUM (R-RU) SYSTEMS

About 20 new compounds have been prepared and identified in the rare earth-ruthenium (R\ue5f8Ru) systems and a complete compound formation scheme has been constructed. Two new crystal structures have been found and completely resolved (Y44Ru25 and Er3Ru2) while for a third one (RRux the complexity of the structure prevented any structural determination. The existence of the various phases is briefly examined by considering the effects of the lanthanide contraction and the valence instability of the rare earths involved