Ternary gallides of the Ce2+nRh3+3nGa1+2n (n = 0—5) structure family

Resumo

The structures of nine ternary intermetallic compounds (IMCs) of the cerium—rhodium—gallium system containing 50 at.% rhodium were determined by single-crystal X-ray diffraction. The compounds are built up of alternating Ce₂Rh₃Ga fragments with the Mg₂Cu₃Si (MgZn₂ type) or Mg₂Ni₃Si (MgCu₂ type) structure and CeRh₃Ga₂ fragments with the CeCo₃B₂ (CaCu₅ type) structure and form a homologous series of the composition R_2+nT_3+3nM_1+2n (n = 0—5). These compounds can be classified into trigonal (R-3m) or hexagonal (P6₃/mmc) branches depending on the Laves phase-type fragment.