Synthesis, crystal structure and properties of RbMnO 2

Abstract

RbMnO 2 was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursers (Mn 2O 3, RbN 3 and RbNO 3) were heated in a special regime up to 600 °C and annealed at this temperature for 30 h in specially designed silver crucibles. Single crystals have been grown by annealing a 1:1 mixture of Rb 2O and MnO x at 585 °C for 1200h. According to the crystal structure determination Mn 3+ is in a square-pyramidal coordination by oxygen. These [MnO 5] units form double chains extending along the crystallographic c-axis. RbMnO 2 shows Curie-Weiss behaviour down to ∼100 K. A fit of the susceptibility data yields an average value of the magnetic moment (per manganese atom) of μ eff = 5.33 μ B, and θ P = -820 K. At 50 K and low field strength onset of ferromagnetic order due to spin canting has been observed. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.