New Sr9Os5O23, Made Up of Quasi 1D and 2D Fragments of the Perovskite Structure

Sr9Os5O23, a new strontium osmate, has been synthesized as a coarse-crystalline material from SrO2 and Os, in a SrCl2 flux. It crystallizes in a rather large monoclinic cell with space group, C2/c. It is a member of a newly identified homologous series Sr2n-1OsnO5n-2 of compounds with n = 3, 5, 7,···. The crystal structure consists of stacks of two-dimensional slabs of perovskite-type layers alternating with one-dimensional zigzag chains of corner sharing OsO6 octahedra. The (Os5+/6+) mixed valence title compound shows an antiferromagnetic-like transition at TN ∼ 75 K, as inferred from magnetic susceptibility data.