No abstract

The synthesis, structure, and elementary magnetic and electronic properties are reported for layered compounds of the type Na 3-x MIr 2 O 6 and Na 3-x M 2 IrO 6 , where M is a transition metal from the 3d series (M=Zn, Cu, Ni, Co, Fe and Mn). The rhombohedral structures, in space group R-3m, were determined by refinement of neutron and synchrotron powder diffraction data. No clear evidence for long range 2:1 or 1:2 honeycomb-like M/Ir ordering was found in the neutron powder diffraction patterns except in the case of M = Zn, and thus in general the compounds are best designated as sodium deficient α-NaFeO 2 -type phases with formulas Na