Synthesis, Crystal Structure, and Magnetic Properties of New OneDimensional Oxides Ca3CoRhO6 and Ca3FeRhO6

One-dimensional compounds Ca3CoRhO6 and Ca3FeRhO6 have been newly synthesized and structurally characterized by Rietveld refinement of powder X-ray diffraction data. Both compounds are isostructural with the rhombohedral K4CdCl6-type structure (space group R c; Z=6; Ca3CoRhO6: a=9.2017(1) ?, c=10.7296(1) ? Ca3FeRhO6: a=9.1960(1) ?, c=10.7861 (1) ?). The structure of Ca3CoRhO6 and Ca3FeRhO6 contains one-dimensional chains consisting of alternating faced-sharing CoO6, FeO6 trigonal prisms, and RhO6 octahedra, respectively. The magnetic susceptibility of Ca3CoRhO6 exhibits an abrupt drop at 35 K, which is also observed in Sr3NiIrO6 and Ca3CoIrO6. Ca3FeRhO6 is an antiferromagnet with TN=12 K.