Preparation, structure and magnetic properties of a new nickel(III) oxide: YbSr3NiO6

An investigation of the Yb2–xSrxNiO4–δ system has shown that no phases crystallise with a K2NiF4 structure for reaction temperatures up to 1100 °C at 1 atm oxygen pressure, but a new phase of ideal composition YbSr3NiO6 is formed. Rietveld refinement using powder X-ray diffraction data shows that YbSr3NiO6 adopts a rhombohedral K4PtCl6 type structure [Rc, Z= 6, a= 9.6851 (2)Å, c= 11.0960(2)Å, Rwp= 2.8%], with a deficiency of scattering from the Yb site due to 11 % Yb vacancies or possibly cation substitutions, lodometric titrations suggest an average Ni oxidation state of 3.0+. Magnetic susceptibility data for YbSr3NiO6 between 5 and 300 K show Curie–Weiss behaviour at higher temperatures, characteristic of Yb3+ and low-spin Ni3+ with overall µeff= 4.63(1)µB and θW=–29.0(1) K. A broad susceptibility maximum at 12 K may be due to one-dimensional antiferromagnetic order.