Sr₂OsO₅ and Sr₇Os₄O₁₉, Two Structurally Related, Mott Insulating Osmates(VI) Exhibiting Substantially Reduced Spin Paramagnetic Response

The new osmates­(VI), Sr₂OsO₅ and Sr₇Os₄O₁₉, feature quasi-1-D polyoxo anions, consisting of corner sharing [OsO₆] octahedra. In both compounds, the magnetic moment at <i>T</i> = 300 K is significantly lower (1.2–1.3 μ_B/Os-atom) than the value expected for <i>S</i> = 1. For neither of the new osmates­(VI) is any evidence for long-range magnetic order found. For Sr₇Os₄O₁₉, magnetic susceptibility suggests an antiferromagnetic ordering at <i>T</i>_N = 43(3) K; however, no corresponding anomaly is visible in specific heat. Both compounds are semiconductors