Synthesis, structure and properties of the oxynitrides SrWO2N and SrMoO2.5N0.5

Two oxynitrides, SrWO2N and SrMoO2.5N0.5, were synthesized by the ammonolysis of SrMO4 (M = W, Mo) at 900 and 800 °C, respectively. Both oxynitrides adopt the cubic perovskite structure (space group Pm3m) with a = 3.97951(9) Å for SrWO2N and a = 3.9773(1) Å for SrMoO2.5N0.5. The M(O,N) and Sr(O,N) bond lengths, determined from the Rietveld refinement of the powder X-ray diffraction data, are in good agreement with those reported for other oxynitrides with the perovskite structure. Nearly temperature independent electrical resistivities were observed for both compounds. The magnetic susceptibility measurements indicated Pauli-paramagnetic behavior in both cases. A sharp anomaly observed in the magnetization data of SrMoO2.5N0.5 at ~50 K has been attributed to a spin-glass-like transition.