Levytskyy V. The compounds of the R-M-C systems (R = rare earth metal, M = 3d-element) and their hydrides: synthesis, structure, and properties

Interaction of the components in the R-M-C systems (R=rare earth metal, M=3d-element) was studied using enhanced sample preparation procedure and modern methods of experimental research. The isothermal sections of the phase diagrams were constructed for 11 ternary systems. As a result of present research 19 ternary compounds were found for the first time. Ce29Cr6C28 and Dy2Mn2-xC5 (0<x<0.6) represent new structure types. New binaries Tb3C4, Dy4C7, metastable CeCr1-x (x~0.89), new modification of TbNi, and concentration polymorphic modification DyMn2-x were found in the investigated systems. Crystal structures of 9 binary compounds were refined with the single-crystal X-ray method. Compositions of 12 new ternaries with unknown structures were determined. Six new R-M-C ternary compounds were synthesized with the structures isotypic with known ones. Ternary compounds are formed mainly in the concentration region triangle 'RC-M-RC2' and their stoichiometric compositions lie on the cross-sections 'binary rare earth carbide - 3d-element'. This observation allows to predict phase equilibria and synthesis of new ternaries in similar not yet investigated systems. Stable in air compounds have only isolated carbon atoms in their crystal structures.