SYNTHESIS OF THE NEW ONE-DIMENSIONAL COMPOUND SR3NIPTO6 - STRUCTURE AND MAGNETIC-PROPERTIES

Single crystals of a new one-dimensional oxide, Sr3NiPtO6, containing Ni(II) in an usual trigonal prismatic coordination were synthesized electrochemically using platinum electrodes in a mixture of SrCO3 and NiO dissolved in a KOH flux. Since the as-grown crystals were twinned, the structure was determined by Rietveld analysis of the X-ray and neutron powder data. The structure was refined in space group R $($) over bar$$ 3c, with a = 9.5832(1) and c = 11.1964(1). Sr3NiPtO6, structurally related to Sr3CuPtO6 and the parent compound A(4)PtO(6) (A = Ca, Sr,Ba), contains infinite chains of alternating, face-sharing PtO6 octahedra and NiO6 trigonal prisms. Magnetic susceptibility studies of Sr3NiPtO6 indicate the presence of Ni(II) ions with large single-ion anisotropy (D = 90.2 K, g = 2.37,(chi TIP) = 5.7 x 10(-4) emu/mol) and the onset of low-dimensional, short-range antiferromagnetic ordering at similar to 25 K. In contrast, Sr3CuPtO6 exhibits S = 1/2 Heisenberg linear chain antiferromagnetism with J/k = -26.1 K and ($) over bar g = 2.21.