ИСТИНА

The direct alloying of cerium, rhodium, and gallium results in the formation of intermetallic compounds with sequence of related structures, forming a new homologous series. Structures of 9 ternary intermetallic compounds of Ce-Rh-Ga system containing 50 at.% of rhodium were determined from single-crystal X-ray diffractometer data. The compounds are built up of columns of alternating combination of the fragments of Ce2Rh3Ga with Mg2Cu3Si structure (MgZn2-type) or Mg2Ni3Si (MgCu2-type) and fragments of CeRh3Ga2 with CeCo3B2 structure (CaCu5-type), forming the homologous series R2+nT3+3nM1+2n (n=0ч6). They can be grouped in two different structural series: trigonal (R-3m) and hexagonal (P63/mmc) group, depending on Laves-type fragment.