Synthesis and Structure of Three New Oxychalcogenides: A2O2Bi2Se3 (A = Sr, Ba) and Sr2O2Sb2Se3

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• 作者：Jessica R. Panella ; Juan Chamorro ; Tyrel M. McQueen
• 刊名：Chemistry of Materials
• 出版年：2016
• 出版时间：February 9, 2016
• 年：2016
• 卷：28
• 期：3
• 页码：890-895
• 全文大小：344K
• ISSN：1520-5002

文摘

Three new compounds have been added to the alkali chalcogenide and oxychalcogenide families: Sr₂O₂Bi₂Se₃, Ba₂O₂Bi₂Se₃, and Sr₂O₂Sb₂Se₃ were synthesized by direct combination of SrO or BaO with Bi₂Se₃ or Sb₂Se₃. The structure, determined from laboratory X-ray powder diffraction data, consists of double chains of edge-sharing BiSe₄O square pyramids. Temperature-dependent resistance data reveal all three compounds to be insulators, while heat capacity data of Ba₂O₂Bi₂Se₃ and Sr₂O₂Bi₂Se₃, in conjunction with the literature reports, reveal low energy phonon modes due to bismuth lone pair effects. We propose a specific materials design principle connecting electron count to structural dimensionality by comparison to related chalcogenides, including the BiS₂ superconductors.