Synthesis, Crystal Structure, and Optical Properties of Layered Perovskite Scandium Oxychlorides: SrScOCl, SrScOCl, and BaScOCl.

Author(s) Su, Y.; Tsujimoto, Y.; Fujii, K.; Tatsuta, M.; Oka, K.; Yashima, M.; Ogino, H.; Yamaura, K.
Journal Inorg Chem
Date Published 2018 May 07

We report the successful synthesis of three new Ruddlesden-Popper-type scandium oxychloride perovskites, SrScOCl, SrScOCl, and BaScOCl, by conventional solid-state reaction. Small single crystals of SrScOCl were obtained by a self-flux method, and the crystal structure was determined to belong to the tetragonal P4/ nmm space group ( a = 4.08066(14) Å, c = 14.1115(8) Å) by X-ray diffraction analysis. The scandium center forms a ScOCl octahedron with ordered apical oxygen and chlorine anions. The scandium cation, however, is shifted from the position of the octahedral center toward the apical oxygen anion, such that the coordination geometry of the Sc cation can be effectively viewed as an ScO pyramid. These structural features in the oxychloride are different from those of octahedral ScOF coordinated with a partial O/F anion order at the apical sites in the oxyfluoride SrScOF. Rietveld refinements of the neutron powder diffraction data of SrScOCl ( I4/ mmm: a = 4.107982(5) Å, c = 23.58454(7) Å) and BaScOCl ( I4/ mmm: a = 4.206920(5) Å, c = 24.54386(6) Å) reveal the presence of pseudo ScO pyramids with the Cl anion being distant from the scandium cation, which is similar to the Sc-centered coordination geometry in SrScOCl with the exception that the ScO pyramids form double layers by sharing the apical oxygen. Density functional calculations on SrScOCl indicate the strong covalency of the Sc-O bonds but almost nonbonding interaction between Sc and Cl ions.

DOI 10.1021/acs.inorgchem.8b00573
ISSN 1520-510X
Citation Inorg Chem. 2018;57(9):56155623.

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