CRYSTAL-STRUCTURE AND MAGNETIC-PROPERTIES OF THE ONE-DIMENSIONAL OXIDE, SR3ZNIRO6 - ZINC IN TRIGONAL PRISMATIC COORDINATION

The structure of Sr3ZnIrO6 was determined by powder X-ray Rietveld ref inement in space group R (3) over bar c (No. 167), a=9.6392(1) and c=1 1.2145(2) Angstrom. Neutron diffraction refinements confirm the struct ure analysis. The structure contains zinc in a highly unusual trigonal prismatic coordination environment. The structure consists of infinit e one-dimensional chains of alternating face-shared IrO6 octahedra and ZnO6 trigonal prisms. Magnetic measurements show that Sr3ZnIrO6 corre lates antiferromagnetically near 20 K. No magnetic ordering, however, was found by the neutron diffraction experiments performed at room tem perature and at 10 K. The magnetic data were fit using an Ising model, which gave a coupling value J/k(B) similar to 18.5. (C) 1996 Academic Press, Inc.